SAN Banco Santander SA

Filed Pursuant to Rule 424(b)(5)
Registration Statement No. 333-271955

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell these securities nor do they seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion

Preliminary Prospectus Supplement dated March 11, 2024

PRELIMINARY PROSPECTUS SUPPLEMENT

(to prospectus dated May 16, 2023)

$    

Banco Santander, S.A.

$     Senior Non Preferred Callable Floating Rate Notes due 2028

$     % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2028

$    % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2030

We are offering $     principal amount of Senior Non Preferred Callable Floating Rate Notes due 2028 (the “SNP 2028 Floating Rate Notes”), $     principal amount of    % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2028 (the “SNP 2028 Fixed-to-Fixed Rate Notes”) and $     principal amount of    % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2030 (the “SNP 2030 Fixed-to-Fixed Rate Notes”, and together with the SNP 2028 Floating Rate Notes and the SNP 2028 Fixed-to-Fixed Rate Notes, the “Notes”).

The SNP 2028 Floating Rate Notes will bear interest at the Floating Rate Interest Rate (as defined herein). From and including the date of issuance, interest will be payable quarterly in arrears on the SNP 2028 Floating Rate Notes on March    , June    , September    , and December    of each year, beginning on June    , 2024. Unless we redeem the SNP 2028 Floating Rate Notes earlier, the SNP 2028 Floating Rate Notes will be due on March    , 2028.

The SNP 2028 Fixed-to-Fixed Rate Notes will bear interest at (i) a fixed rate of    % per annum in respect of the period from (and including) the date of issuance to (but excluding) March    , 2027 (the “SNP 2028 Reset Date”) and (ii) a fixed rate equal to the applicable U.S. Treasury Rate as of the SNP 2028 Reset Determination Date (as such terms are defined herein) plus    % per annum in respect of the period from (and including) the SNP 2028 Reset Date to (but excluding) March    , 2028. From and including the date of issuance, interest will be payable semi-annually in arrears on the SNP 2028 Fixed-to-Fixed Rate Notes on March    and September    of each year, beginning on September    , 2024. Unless we redeem the SNP 2028 Fixed-to-Fixed Rate Notes earlier, the SNP 2028 Fixed-to-Fixed Rate Notes will be due on March    , 2028.

The SNP 2030 Fixed-to-Fixed Rate Notes will bear interest at (i) a fixed rate of    % per annum in respect of the period from (and including) the date of issuance to (but excluding) March    , 2029 (the “SNP 2030 Reset Date”) and (ii) a fixed rate equal to the applicable U.S. Treasury Rate as of the SNP 2030 Reset Determination Date (as such term is defined herein) plus    % per annum in respect of the period from (and including) the SNP 2030 Reset Date to (but excluding) March    , 2030. From and including the date of issuance, interest will be payable semi-annually in arrears on the SNP 2030 Fixed-to-Fixed Rate Notes on March    and September    of each year, beginning on September    , 2024. Unless we redeem the SNP 2030 Fixed-to-Fixed Rate Notes earlier, the SNP 2030 Fixed-to-Fixed Rate Notes will be due on March    , 2030.

The Notes will be issued in minimum denominations of $200,000 and integral multiples of $200,000 in excess thereof.

The payment obligations of Banco Santander, S.A. (“Banco Santander”) in respect of principal under the Notes constitute direct, unconditional, unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander and, in accordance with Additional Provision 14.2 of Law 11/2015 (as defined herein), but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, such payment obligations rank (i)

pari passu among themselves and with any other Senior Non Preferred Liabilities (as defined herein), (ii) junior to the Senior Higher Priority Liabilities (as defined herein) (and, accordingly, upon the insolvency of Banco Santander, the payment obligations of Banco Santander in respect of principal under the Notes will be met after payment in full of the Senior Higher Priority Liabilities) and (iii) senior to any present and future subordinated obligations (créditos subordinados) of Banco Santander in accordance with Article 281 of the Spanish Insolvency Law (as defined herein).

By its acquisition of the Notes, each holder (which, for the purposes of this clause, includes each holder of a beneficial interest in the Notes) acknowledges, accepts, consents to and agrees to be bound by the terms of the Notes related to the exercise of the Bail-in Power (as defined herein) set forth under “Description of Debt Securities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power” in the accompanying prospectus. See “Notice to Investors” on page S-i of this prospectus supplement for further information.

The Notes are not deposits or savings accounts and are not insured by the Federal Deposit Insurance Corporation or any other governmental agency of the Kingdom of Spain, the United States or any other jurisdiction.

We may redeem the Notes of any series, in whole but not in part, at 100% of their principal amount plus accrued and unpaid interest (if any) at any time (i) upon the occurrence of certain tax events, (ii) upon the occurrence of certain regulatory events set forth herein or (iii) on the relevant optional redemption date. We may not redeem the Notes of any series under other circumstances.

We intend to apply to list the Notes on the New York Stock Exchange in accordance with its rules.

Investing in the Notes involves risks. See “Risk Factors” beginning on page S-15 of this prospectus supplement, page 5 of the accompanying prospectus as well as those discussed under the heading “Risk Factors” in the Group’s Annual Report on Form 20-F for the year ended December 31, 2023, which is incorporated by reference herein.

The Notes are not intended to be offered, sold or otherwise made available and should not be offered, sold or otherwise made available to retail clients (as defined in Directive 2014/65/EU of the European Parliament and of the Council on Markets in Financial Instruments (“MiFID II”) and Regulation (EU) No. 2017/565 as it forms part of the domestic law of the United Kingdom by virtue of the European Union (Withdrawal) Act of 2018 (“EUWA”)) in the European Economic Area or in the United Kingdom. Prospective investors are referred to the section headed “Important Information” on page S-v of this prospectus supplement.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

The initial public offering prices set forth above do not include accrued interest, if any. Interest on the Notes will accrue from the expected date of issuance, which is March    , 2024. See “Underwriting (Conflicts of Interest).”

We expect that the Notes will be ready for delivery through the book-entry facilities of The Depository Trust Company (“DTC”) and its direct and indirect participants, including Clearstream Banking, société anonyme (“Clearstream Luxembourg”) and Euroclear Bank SA/NV (“Euroclear”) on or about March    , 2024, which will be the    New York business day following the pricing of the Notes (such settlement period being referred to as “T+    ”). Beneficial interests in the Notes will be shown on, and transfers thereof will be effected only through, records maintained by DTC and its participants.

Joint Bookrunners

Prospectus Supplement dated March    , 2024

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

NOTICE TO INVESTORS

Agreements and Acknowledgments of Investors, including Holders and Beneficial Owners

Notwithstanding any other term of the Notes or any other agreements, arrangements, or understandings between Banco Santander and any holder of the Notes, by its acquisition of the Notes, each holder (which includes each holder of a beneficial interest in the Notes) acknowledges, accepts, consents to and agrees:

(i) to be bound by the effect of the exercise of the Bail-in Power by the Relevant Resolution Authority (as defined herein), which may include and result in any of the following, or some combination thereof:

(ii) that the terms of the Notes are subject to, and may be varied, if necessary, to give effect to, the exercise of the Bail-in Power by the Relevant Resolution Authority.

For these purposes, “Amounts Due” are the principal amount of, premium, if any, together with any accrued but unpaid interest, and Additional Amounts (as defined herein), if any, due on the Notes. References to such amounts will include amounts that have become due and payable, but which have not been paid, prior to the exercise of the Bail-in Power by the Relevant Resolution Authority.

“Applicable Banking Regulations” means at any time the laws, regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, then applicable to Banco Santander and/or the Group including, without limitation to the generality of the foregoing, the CRD IV, the BRRD, the SRM Regulation and those regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency of the Regulator then applicable to Banco Santander and/or the Group including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, in each case to the extent then in effect in the Kingdom of Spain (whether or not such regulations, requirements, guidelines or policies have the force of law and whether or not they are applied generally or specifically to Banco Santander and/or the Group).

For these purposes, a “Bail-in Power” means any power existing from time to time under, and exercised in compliance with, any laws, regulations, rules or requirements in effect in the Kingdom of Spain, relating to (i) the transposition of the BRRD (as defined herein), including its article 48 and, when applicable, its article 59 (therefore, the write-down capital conversion power at the point of non-viability) (including but not limited to, Law 11/2015, RD 1012/2015 (as defined herein) and any other implementing regulations), (ii) the SRM Regulation (as defined herein) and (iii) the instruments, rules or standards created thereunder, pursuant to which any obligation of a Regulated Entity (as defined herein) (or an

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affiliate of such Regulated Entity) can be reduced, cancelled, suspended, modified, or converted into shares, other securities, or other obligations of such Regulated Entity (or affiliate of such Regulated Entity).

“BRRD” means Directive 2014/59/EU of 15 May establishing a framework for the recovery and resolution of credit institutions and investment firms or such other directive as may come into effect in place thereof, as amended or replaced from time to time.

“CET1 Capital” means at any time, the common equity tier 1 capital of Banco Santander or the Group, respectively, as calculated in accordance with Chapter 2 (Common Equity Tier 1 Capital) of Title I (Elements of own funds) of Part Two (Own Funds and Eligible Liabilities) of the CRR and/or Applicable Banking Regulations at such time, including any applicable transitional, phasing in or similar provisions.

“Common Equity Tier 1 Instruments” means instruments qualifying as CET1 Capital.

“CRD IV” means any or any combination of the CRD IV Directive, the CRR, and any CRD IV Implementing Measures.

“CRD IV Directive” means Directive 2013/36/EU of the European Parliament and of the Council of 26 June 2013 on access to the activity of credit institutions and the prudential supervision of credit institutions and investment firms or such other directive as may come into effect in place thereof, as amended or replaced from time to time.

“CRD IV Implementing Measures” means any regulatory capital rules implementing the CRD IV Directive or the CRR which may from time to time be introduced, including, but not limited to, delegated or implementing acts (regulatory technical standards) adopted by the European Commission, national laws and regulations, and regulations and guidelines issued by the Regulator, the European Banking Authority or any other relevant authority, which are applicable to Banco Santander (on a standalone basis) or the Group (on a consolidated basis) and which prescribe the requirements to be fulfilled by financial instruments for inclusion in the regulatory capital or the minimum requirement for own funds and eligible liabilities, as the case may be, of Banco Santander (on a standalone basis) or the Group (on a consolidated basis).

“CRR” means Regulation (EU) No. 575/2013 of the European Parliament and of the Council of 26 June 2013 on the prudential requirements for credit institutions and investment firms or such other regulation as may come into effect in place thereof, as amended or replaced from time to time.

“Law 11/2015” means Law 11/2015 of 18 June, on recovery and resolution of credit institutions and investment firms (Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión), as amended or replaced from time to time.

“MREL” means the “minimum requirement for own funds and eligible liabilities” for credit institutions under the BRRD, set in accordance with Article 45 of the BRRD (as transposed in the Kingdom of Spain), Commission Delegated Regulation (EU) No. 2016/1450 of 23 May 2016, supplementing Directive 2014/59/EU of the European Parliament and of the Council with regard to regulatory technical standards specifying the criteria relating to the methodology for setting the minimum requirement for own funds and eligible liabilities and any other Applicable Banking Regulations.

“RD 1012/2015” means Royal Decree 1012/2015, of 6 November, implementing Law 11/2015, of 18 June, on the recovery and resolution of credit institutions and investment firms (Real Decreto 1012/2015, de 6 de noviembre, por el que se desarrolla la Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión), as amended or replaced from time to time.

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“Regulated Entity” means any entity to which BRRD, as implemented in the Kingdom of Spain (including but not limited to, Law 11/2015, RD 1012/2015 and any other implementing regulations), or any other Spanish law relating to the Bail-in Power, applies, which includes, certain credit institutions, investment firms, and certain of their parent or holding companies.

“Regulator” means the European Central Bank, the Bank of Spain, the Relevant Resolution Authority or such other or successor authority exercising primary bank supervisory authority or the role of primary bank resolution authority, in each case with respect to prudential or resolution matters in relation to Banco Santander and/or the Group.

A reference to the “Relevant Resolution Authority” is to the Spanish Fund for the Orderly Restructuring of Banks, the Bank of Spain, the European Single Resolution Board, as the case may be, according to Law 11/2015, and any other entity with the authority to exercise the Bail-in Power or any other resolution power from time to time.

“SRM Regulation” means Regulation (EU) No. 806/2014 of the European Parliament and of the Council of 15 July 2014, establishing uniform rules and a uniform procedure for the resolution of credit institutions and certain investment firms in the framework of a Single Resolution Mechanism and a Single Resolution Fund, as amended or replaced from time to time.

“TLAC” means the “total loss-absorbing capacity” requirement for global systemically important institutions under the CRR, set in accordance with Article 92a of the CRR and/or any other Applicable Banking Regulations.

By its acquisition of the Notes, each holder of the Notes (which, for the purposes of this clause, includes each holder of a beneficial interest in the Notes), to the extent permitted by the Trust Indenture Act of 1939, as amended (“Trust Indenture Act”), will waive any and all claims, in law and/or in equity, against the Trustee (as defined herein) for, agree not to initiate a suit against the Trustee in respect of, and agree that the Trustee will not be liable for, any action that the Trustee takes, or abstains from taking, in either case in accordance with the exercise of the Bail-in Power by the Relevant Resolution Authority with respect to the Notes.

By purchasing the Notes, each holder (including each beneficial owner) of the Notes shall be deemed to have authorized, directed and requested DTC and any direct participant in DTC or other intermediary through which it holds the Notes to take any and all necessary action, if required, to implement the exercise of the Bail-in Power with respect to the Notes as it may be imposed, without any further action or direction on the part of such holder.

Neither Banco Santander nor the Underwriters (as defined in “Underwriting (Conflicts of Interest)” in this prospectus supplement) have authorized anyone to provide you with information other than information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus (including any free writing prospectus issued or authorized by us). The distribution of this prospectus supplement and the accompanying prospectus and the offering of the Notes in some jurisdictions may be restricted by law. If you possess this prospectus supplement and the accompanying prospectus, you should find out about and observe these restrictions. This prospectus supplement and the accompanying prospectus are not an offer to sell the Notes and neither Banco Santander nor the Underwriters are soliciting an offer to buy the Notes in any jurisdiction where the offer or sale is not permitted or where the person making the offer or sale is not qualified to do so or from any person to whom it is not permitted to make such offer or sale. We refer you to the information under “Underwriting (Conflicts of Interest)” in this prospectus supplement. You should assume that the information contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference is accurate only as of their respective dates.

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ABOUT THIS PROSPECTUS SUPPLEMENT

In this prospectus supplement, we use the following terms:

This document is not a prospectus for the purposes of Regulation (EU) No. 2017/1129 of the European Parliament and of the Council of 14 June 2017 on the prospectus to be published when securities are offered to the public or admitted to trading on a regulated market, and repealing Directive 2003/71/EC (the “Prospectus Regulation”). This document has been prepared on the basis that all offers of the Notes offered hereby made to persons in the European Economic Area (“EEA”) or in the United Kingdom (“UK”) will be made pursuant to an exemption under the Prospectus Regulation from the requirement to produce a prospectus in connection with offers of such Notes.

The communication of this document and any other document or materials relating to the issue of the Notes offered hereby is not being made, and such documents and/or materials have not been approved, by an authorized person for the purposes of section 21 of the UK’s Financial Services and Markets Act 2000, as amended (“FSMA”). Accordingly, such documents and/or materials are not being distributed to, and must not be passed on to, the general public in the UK. The communication of such documents and/or materials as a financial promotion is only being made to and directed at persons outside the UK and those persons in the UK falling within the definition of investment professionals (as defined in Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Financial Promotion Order”)), or within Article 49(2)(a) to (d) of the Financial Promotion Order, or to any other persons to whom it may otherwise lawfully be made under the Financial Promotion Order (all such persons together being referred to as “relevant persons”). In the UK, the Notes offered hereby are only available to, and any investment or investment activity to which this document relates will be engaged in only with, relevant persons. Any person in the UK that is not a relevant person should not act or rely on this document or any of its contents.

INCORPORATION OF INFORMATION BY REFERENCE

This prospectus supplement is part of a registration statement on Form F-3 (File No. 333-271955) filed with the SEC under the Securities Act. This prospectus supplement omits some information contained in the registration statement in accordance with SEC rules and regulations. You should review the information in and exhibits to the registration statement for further information on us and the Notes. Statements in this prospectus supplement concerning any document we filed or will file as an exhibit to the registration statement or that we otherwise filed with the SEC are not intended to be comprehensive and are qualified in their entirety by reference to these filings. You should review the complete document to evaluate these statements.

The SEC allows us to “incorporate by reference” the information that we file with the SEC. This permits us to disclose important information to you by referring to these filed documents. Any information referred to in this way is considered part of this prospectus supplement and accompanying prospectus, and any information that we file with the SEC after the date of this prospectus supplement will automatically be deemed to update and supersede this information.

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We incorporate by reference the Group’s Annual Report on Form 20-F for the year ended December 31, 2023, filed with the SEC on February 21, 2024.

We also incorporate by reference all subsequent annual reports of the Group filed on Form 20-F and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, and certain reports on Form 6-K, if they state that they are incorporated by reference into the registration statement of which this prospectus supplement forms a part, that we furnish to the SEC after the date of this prospectus supplement and until the Underwriters sell all of the Notes.

Upon written or oral request, we will provide free of charge a copy of any or all of the documents that we incorporate by reference into this prospectus supplement, other than exhibits which are not specifically incorporated by reference into this prospectus supplement. To obtain copies you should contact us at Investor Relations, Ciudad Grupo Santander, Avenida de Cantabria s/n, 28660 Boadilla del Monte, Madrid, Spain (telephone: (011) 34-91-259-6520).

FORWARD-LOOKING STATEMENTS

From time to time, we may make statements, both written and oral, regarding assumptions, projections, expectations, intentions or beliefs about future events. These statements constitute “forward-looking statements” for purposes of the Private Securities Litigation Reform Act of 1995. We caution that these statements may and often do vary materially from actual results. Accordingly, we cannot assure you that actual results will not differ materially from those expressed or implied by the forward-looking statements. You should read the sections entitled “Risk Factors” in this prospectus supplement and the accompanying prospectus and “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in our Annual Report on Form 20-F for the year ended December 31, 2023, which is incorporated by reference herein.

We do not undertake any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. In light of these risks, uncertainties and assumptions, forward-looking events discussed in this prospectus supplement and the accompanying prospectus or any information incorporated by reference, might not occur.

IMPORTANT INFORMATION

EU PRIIPs Regulation/Prohibition of Sales to EEA Retail Investors – The Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the EEA. For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client, as defined in point (11) of Article 4(1) of MiFID II; (ii) a customer within the meaning of Directive (EU) 2016/97 (as amended, the “IDD”), where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II; or (iii) not a qualified investor as defined in the Prospectus Regulation. Consequently, no key information document required by Regulation (EU) No. 1286/2014 (the “EU PRIIPs Regulation”) for offering or selling the Notes or otherwise making them available to retail investors in the EEA has been prepared and therefore offering or selling the Notes or otherwise making them available to any retail investor in the EEA may be unlawful under the EU PRIIPs Regulation.

UK PRIIPs Regulation/Prohibition of Sales to UK Retail Investors – The Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the UK. For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client, as defined in point (8) of Article 2 of Regulation (EU) No. 2017/565 as it forms part of UK domestic law by virtue of the EUWA; or (ii) a customer within the meaning of the provisions of the FSMA and any rules or regulations made under the FSMA to implement IDD, where that customer would not qualify as a professional

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client, as defined in point (8) of Article 2(1) of Regulation (EU) No. 600/2014 as it forms part of UK domestic law by virtue of the EUWA. Consequently, no key information document required by Regulation (EU) No. 1286/2014 as it forms part of UK domestic law by virtue of the EUWA (the “UK PRIIPs Regulation”) for offering or selling the Notes or otherwise making them available to retail investors in the UK has been prepared and therefore offering or selling the Notes or otherwise making them available to any retail investor in the UK may be unlawful under the UK PRIIPs Regulation.

MIFID II product governance/Professional investors and ECPs only target market – Solely for the purposes of each manufacturer’s product approval process, the target market assessment in respect of the Notes has led to the conclusion that: (i) the target market for the Notes is eligible counterparties and professional clients only, each as defined in MiFID II; and (ii) all channels for distribution of the Notes to eligible counterparties and professional clients are appropriate. The target market assessment indicates that the Notes are incompatible with the needs, characteristics and objectives of clients which are retail clients (as defined in MiFID II). Any person subsequently offering, selling or recommending the Notes (a “distributor”) should take into consideration the manufacturers’ target market assessment; however, a distributor subject to MiFID II is responsible for undertaking its own target market assessment in respect of the Notes (by either adopting or refining the manufacturers’ target market assessment) and determining appropriate distribution channels.

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RISK FACTORS

Before purchasing the Notes, you should consider carefully the information under the heading “Risk Factors” in the Group’s Annual Report on Form 20-F for the year ended December 31, 2023. The Notes are also subject to the risks identified in the accompanying prospectus under the headings “Risks Relating to the Securities”, “Risks Relating to the Debt Securities”, and “Risks Related to the Senior Non Preferred Debt Securities”. You should also carefully consider the other information included in this prospectus supplement, the accompanying prospectus and other information incorporated by reference herein and therein. Each of the risks set forth in these documents could materially and adversely affect our business, financial condition, results of operations and prospects, or could result in a partial or complete loss of your investment. See “Where You Can Find More Information” in the accompanying prospectus.

Risks Relating to the SNP 2028 Floating Rate Notes

The following discussion supplements the information under the heading “Risk Factors” in the accompanying prospectus.

SOFR has a limited history and its future performance cannot be predicted based on historical performance.

The publication of SOFR began on April 3, 2018, and it therefore has a limited history. In addition, the future performance of SOFR cannot be predicted based on the limited historical performance. The level of SOFR, which will be used to calculate Compounded SOFR, may bear little or no relation to the historical level of SOFR. Prior observed patterns, if any, in the behavior of market variables and their relation to SOFR, such as correlations, may change in the future. While pre-publication indicative historical data has been released by the Federal Reserve Bank of New York, such analysis inherently involves assumptions, estimates and approximations. The future performance of SOFR is impossible to predict and therefore no future performance of SOFR or the SNP 2028 Floating Rate Notes may be inferred from any of the historical simulations or historical performance. Hypothetical or historical performance data are not indicative of, and have no bearing on, the potential performance of SOFR or the SNP 2028 Floating Rate Notes.

Any failure of SOFR to maintain market acceptance could adversely affect the SNP 2028 Floating Rate Notes.

SOFR is a relatively new rate and may fail to maintain market acceptance. SOFR was developed for use in certain U.S. Dollar derivatives and other financial contracts as an alternative to U.S. Dollar London Interbank Offered Rate (“LIBOR”) in part because it is considered a good representation of general funding conditions in the overnight U.S. Treasury repo market. However, as a rate based on transactions secured by U.S. Treasury securities, it does not measure bank-specific credit risk and, as a result, is less likely to correlate with the unsecured short-term funding costs of banks. This may mean that market participants would not consider SOFR a suitable substitute or successor for all of the purposes for which LIBOR historically has been used (including, without limitation, as a representation of the unsecured short-term funding costs of banks), which may, in turn, lessen market acceptance of SOFR. Any failure of SOFR to maintain market acceptance could adversely affect the value of and your return on the SNP 2028 Floating Rate Notes and the price at which you can sell the SNP 2028 Floating Rate Notes.

The interest rate on the SNP 2028 Floating Rate Notes is based on a daily compounded SOFR rate, which is relatively new in the marketplace.

For each Interest Period, the interest rate on the SNP 2028 Floating Rate Notes is based on a daily compounded SOFR rate calculated using the specific formula set forth herein, not the SOFR rate published on or in respect of a particular date during the related Observation Period or an average of SOFR rates during such

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period. For this and other reasons, the interest rate on the SNP 2028 Floating Rate Notes during any Observation Period will not be the same as the interest rate on other SOFR-linked investments that use an alternative basis to determine the applicable interest rate. Further, if the SOFR rate in respect of a particular date during an Observation Period is negative, the inclusion of such SOFR rate to determine Compounded SOFR for the related Interest Period will reduce the interest rate payable on the SNP 2028 Floating Rate Notes on the related Floating Interest Payment Date; provided that in no event will the interest payable on the SNP 2028 Floating Rate Notes for any Interest Period be less than zero.

In addition, limited market precedent exists for securities that use SOFR as the interest rate and the method for calculating an interest rate based upon SOFR in those precedents varies. Accordingly, the specific formula for the daily compounded SOFR rate used in the SNP 2028 Floating Rate Notes may not be widely adopted by other market participants, if at all. If the market adopts a different calculation method, that would likely adversely affect the return on, value of and market for the SNP 2028 Floating Rate Notes.

The amount of interest payable in respect of the SNP 2028 Floating Rate Notes with respect to each Interest Period will be determined near the end of the Interest Period.

For the SNP 2028 Floating Rate Notes, the Compounded SOFR applicable to each Interest Period and, therefore, the amount of interest payable with respect to such Interest Period will be determined near the end of such Interest Period. Therefore, you will not know the amount of interest payable with respect to each such Interest Period until shortly prior to the related Floating Interest Payment Date and it may be difficult for you to reliably estimate the amount of interest that will be payable on each such Floating Interest Payment Date. This inability to estimate the amount of interest payable on a Floating Interest Payment Date may cause some investors to be unwilling or unable to trade in the SNP 2028 Floating Rate Notes, which could adversely impact the liquidity and value of the SNP 2028 Floating Rate Notes. In addition, with respect to the final Interest Period, holders of the SNP 2028 Floating Rate Notes will not benefit from any increase in the level of SOFR that occurs between the final day of the Observation Period related to such Interest Period and the SNP 2028 Floating Rate Notes Maturity Date.

The composition and characteristics of SOFR are not the same as those of LIBOR.

In June 2017, the Federal Reserve Bank of New York’s Alternative Reference Rates Committee announced SOFR as its recommended alternative to U.S. Dollar LIBOR. However, the composition and characteristics of SOFR are not the same as those of LIBOR. SOFR is a broad Treasury repo financing rate that represents overnight secured funding transactions. This means that SOFR differs from LIBOR (or any other alternative reference rate to LIBOR) in key respects. For example, SOFR is a secured overnight rate that does not embed a credit risk premium, while LIBOR is an unsecured rate that includes an interbank funding premium. In addition, because SOFR is a transaction-based rate, it is backward-looking and Compounded SOFR is the compounded average of daily SOFRs calculated in arrears while LIBOR is a forward-looking rate that is published with different maturities that represents interbank funding over different maturities. As a result, there can be no assurance that SOFR will perform in the same way as LIBOR would have at any time, including, without limitation, as a result of changes in interest and yield rates in the market, market volatility or global or regional economic, financial, political, regulatory, judicial or other events. For example, since publication of SOFR began on April 3, 2018, daily changes in SOFR have, on occasion, been more volatile than daily changes in comparable benchmark or other market rates. Uncertainty surrounding the establishment of market conventions related to the calculation of Compounded SOFR and whether it is a suitable substitute or successor for LIBOR may adversely affect the value of and your return on the SNP 2028 Floating Rate Notes.

The SOFR administrator may make changes that could change the value of SOFR or discontinue SOFR and has no obligation to consider your interests in doing so.

SOFR, which will be used to calculate Compounded SOFR, is a relatively new rate, and the Federal Reserve Bank of New York (or a successor), as administrator of SOFR, may make methodological or other changes that could change the value of SOFR, including changes related to the method by which SOFR is calculated,

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eligibility criteria applicable to the transactions used to calculate SOFR, or timing related to the publication of SOFR. In addition, the administrator may alter, discontinue or suspend calculation or dissemination of SOFR (in which case an alternative rate referenced in the definition of “Benchmark Replacement” will apply). The administrator has no obligation to consider your interests in calculating, adjusting, converting, revising or discontinuing SOFR. For purposes of the formula used to calculate the amount of interest payable on the SNP 2028 Floating Rate Notes, SOFR in respect of a particular date will not be adjusted for any modifications, corrections or amendments to SOFR data that the administrator of SOFR may publish after SOFR for such day has been determined as set forth herein.

If a Benchmark Transition Event and its related Benchmark Replacement Date occur with respect to Compounded SOFR (including daily SOFR), the interest rate on the SNP 2028 Floating Rate Notes for any applicable Interest Period will no longer be determined by reference to Compounded SOFR.

If a Benchmark Transition Event and its related Benchmark Replacement Date (as such terms are defined herein) occur with respect to Compounded SOFR (including daily SOFR), then the interest rate on the SNP 2028 Floating Rate Notes for any applicable Interest Period will no longer be determined by reference to Compounded SOFR, but instead will be determined by us or our designee by reference to another rate, as set forth under “Description of the Notes—The SNP 2028 Floating Rate Notes”. The composition and characteristics of any Benchmark Replacement (as defined herein) may not be the same as Compounded SOFR (including daily SOFR) and there can be no guarantee that any Benchmark Replacement will be a comparable substitute for Compounded SOFR (including daily SOFR). The occurrence of a Benchmark Transition Event and its related Benchmark Replacement Date and the implementation of a Benchmark Replacement may adversely affect the value of and your return on the SNP 2028 Floating Rate Notes.

The Benchmark Replacement is uncertain.

The SNP 2028 Floating Rate Notes provide that the floating rate of interest on the notes will be determined by reference to Compounded SOFR or another rate pursuant to the definition of “Benchmark Replacement” set forth under “Description of the Notes—The SNP 2028 Floating Rate Notes”. If each alternative rate referenced in the definition of “Benchmark Replacement” is unavailable or indeterminable, we or our designee will determine the Benchmark Replacement that will apply to the SNP 2028 Floating Rate Notes. The substitution of a Benchmark Replacement for Compounded SOFR may adversely affect the value of and your return on the SNP 2028 Floating Rate Notes.

We or our designee will have authority to make determinations, elections, calculations and adjustments that could affect the value of and your return on the SNP 2028 Floating Rate Notes.

We or our designee will make determinations, decisions, elections, calculations and adjustments as set forth under “Description of the Notes—The SNP 2028 Floating Rate Notes” below that may adversely affect the value of and your return on the SNP 2028 Floating Rate Notes. In particular, we or our designee will determine the Benchmark Replacement and the Benchmark Replacement Adjustment (as defined herein) and can apply any Benchmark Replacement Conforming Changes (as defined herein) deemed reasonably necessary to adopt the Benchmark Replacement. Although we or our designee will exercise judgment in good faith when performing such functions, potential conflicts of interest may exist between us, our designee and you. All determinations, decisions, elections, calculations and adjustments by us or our designee in our or its sole discretion will be conclusive for all purposes and binding on us and holders of the notes absent manifest error. In making the determinations, decisions, elections, calculations and adjustments noted under the section entitled “Description of the Notes—The SNP 2028 Floating Rate Notes” below, we or our designee may have economic interests that are adverse to your interests, and such determinations, decisions, elections, calculations and adjustments may adversely affect the value of and your return on the notes. Because the Benchmark Replacement is uncertain, we or our designee are likely to exercise more discretion in respect of calculating interest payable on the SNP 2028 Floating Rate Notes than would be the case in the absence of a Benchmark Transition Event and its related Benchmark Replacement Date.

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The secondary trading market for the SNP 2028 Floating Rate Notes linked to SOFR may be limited.

Since SOFR is a relatively new benchmark rate, the SNP 2028 Floating Rate Notes may have no established trading market when issued and an established trading market may never develop or may not be very liquid. Market terms for debt securities linked to SOFR (such as the SNP 2028 Floating Rate Notes) such as the spread may evolve over time and, as a result, trading prices of the SNP 2028 Floating Rate Notes may be lower than those of later-issued debt securities that are linked to SOFR. Similarly, if SOFR does not prove to be widely used in debt securities similar to the SNP 2028 Floating Rate Notes, the trading price of the SNP 2028 Floating Rate Notes may be lower than that of comparable debt securities linked to rates that are more widely used. Investors in the SNP 2028 Floating Rate Notes may not be able to sell such SNP 2028 Floating Rate Notes at all or may not be able to sell such SNP 2028 Floating Rate Notes at prices that will provide them with a yield comparable to similar investments that have a developed secondary market. Further, investors wishing to sell the SNP 2028 Floating Rate Notes in the secondary market will have to make assumptions as to the future performance of SOFR during the Interest Period in which they intend the sale to take place. As a result, investors may suffer from increased pricing volatility and market risk.

Risks Relating to the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes

The following discussion supplements the information under the heading “Risk Factors” in the accompanying prospectus.

The interest rate on the SNP 2028 Fixed-to-Fixed Rate Notes will reset on the SNP 2028 Reset Date, and the interest rate on the SNP 2030 Fixed-to-Fixed Rate Notes will reset on the SNP 2030 Reset Date.

The interest rate on the SNP 2028 Fixed-to-Fixed Rate Notes will initially be    % per annum in respect of the period from (and including) the date of issuance to (but excluding) the SNP 2028 Reset Date. On the SNP 2028 Reset Date, the interest rate will be reset such that the applicable per annum interest rate on the SNP 2028 Fixed-to-Fixed Rate Notes in respect of the period from (and including) the SNP 2028 Reset Date to (but excluding) the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date will be a fixed rate equal to the applicable U.S. Treasury Rate as of the SNP 2028 Reset Determination Date plus    %. The interest rate on the SNP 2030 Fixed-to-Fixed Rate Notes will initially be    % per annum in respect of the period from (and including) the date of issuance to (but excluding) the SNP 2030 Reset Date. On the SNP 2030 Reset Date, the interest rate will be reset such that the applicable per annum interest rate on the SNP 2030 Fixed-to-Fixed Rate Notes in respect of the period from (and including) the SNP 2030 Reset Date to (but excluding) the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date will be a fixed rate equal to the applicable U.S. Treasury Rate as of the SNP 2030 Reset Determination Date plus    %.

As a result, the interest rate following the SNP 2028 Reset Date and the SNP 2030 Reset Date may be less than the relevant initial interest rate, which would affect the amount of any interest payments under the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable, and, by extension, could affect their market value.

The historical U.S. Treasury Rates are not an indication of future U.S. Treasury Rates.

The historical U.S. Treasury Rates are not an indication of future U.S. Treasury Rates. The interest rate on the SNP 2028 Fixed-to-Fixed Rate Notes from and including the SNP 2028 Reset Date to, but excluding, the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date will be reset to a fixed per annum rate to be determined based on the applicable U.S. Treasury Rate on the SNP 2028 Reset Determination Date. The interest rate on the SNP 2030 Fixed-to-Fixed Rate Notes from and including the SNP 2030 Reset Date to, but excluding, the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date will be reset to a fixed per annum rate to be determined based on the applicable U.S. Treasury Rate on the SNP 2030 Reset Determination Date. In the past, U.S. Treasury Rates

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have experienced significant fluctuations. You should note that historical levels, fluctuations and trends of U.S. Treasury Rates are not necessarily indicative of future levels. Any historical upward or downward trend in U.S. Treasury Rates is not an indication that U.S. Treasury Rates are more or less likely to increase or decrease at any time, and you should not take the historical U.S. Treasury Rates as an indication of future rates. You bear the financial risks of fluctuations in the U.S. Treasury Rates and their effect on the interest on, and the market value of, the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable.

Risks Relating to the Notes

The following discussion supplements the information under the heading “Risk Factors” in the accompanying prospectus.

There are limitations to our gross-up obligation on the Notes.

Our obligation to pay Additional Amounts in respect of any withholding or deduction in respect of taxes on the Notes of any series applies only to payments of interest and not to payments of principal or premium, as set forth under “Description of the Notes—Additional Amounts.” Therefore, we will not be required to pay any Additional Amounts on the Notes of any series with respect to any withholding or deduction applied to payments of principal or amounts payable on redemption. Accordingly, if any such withholding or deduction were to apply to any payments of principal or redemption amounts on the Notes of any series, holders of Notes of such series may receive less than the full amount due under the Notes of such series, and the market value of the Notes of any series may be adversely affected.

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USE OF PROCEEDS

The net proceeds from the sale of the Notes are expected to amount to approximately $    after the deduction of the underwriting discount stated on the cover of this prospectus supplement and expenses incurred in connection with this offering (estimated to be an aggregate of approximately $    ). Additionally, the Underwriters have agreed to reimburse us for approximately $    of such expenses. These proceeds and the proceeds of the Concurrent Offering will be used for general corporate purposes.

Settlement of this offering is not conditioned upon settlement of the Concurrent Offering or vice versa. The Concurrent Offering is only being made pursuant to a separate prospectus supplement.

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SECURED OVERNIGHT FINANCING RATE

The Secured Overnight Financing Rate is published by the New York Federal Reserve and is intended to be a broad measure of the cost of borrowing cash overnight collateralized by U.S. Treasury securities. The New York Federal Reserve reports that the Secured Overnight Financing Rate includes all trades in the Broad General Collateral Rate (as defined by the New York Federal Reserve), plus bilateral U.S. Treasury repo transactions cleared through the delivery-versus-payment service offered by the Fixed Income Clearing Corporation (the “FICC”), a subsidiary of DTC. The Secured Overnight Financing Rate is filtered by the New York Federal Reserve to remove a portion of the foregoing transactions considered to be “specials.” According to the New York Federal Reserve, “specials” are repos for specific-issue collateral, which take place at cash-lending rates below those for general collateral repos because cash providers are willing to accept a lesser return on their cash in order to obtain a particular security.

The New York Federal Reserve reports that the Secured Overnight Financing Rate is calculated as a volume-weighted median of transaction-level tri-party repo data collected from The Bank of New York Mellon as well as general collateral finance repurchase agreement transaction data and data on bilateral U.S. Treasury repurchase transactions cleared through the FICC’s delivery-versus-payment service. The New York Federal Reserve notes that it obtains information from DTCC Solutions LLC, an affiliate of DTC. If data for a given market segment were unavailable for any day, then the most recently available data for that segment would be utilized, with the rates on each transaction from that day adjusted to account for any change in the level of market rates in that segment over the intervening period. The Secured Overnight Financing Rate would be calculated from this adjusted prior day’s data for segments where current data were unavailable, and unadjusted data for any segments where data were available. To determine the change in the level of market rates over the intervening period for the missing market segment, the New York Federal Reserve would use information collected through a daily survey conducted by its trading desk of primary dealers’ repo borrowing activity. Such daily survey may include information reported by the underwriters for this offering or their affiliates. The New York Federal Reserve notes on its publication page for the Secured Overnight Financing Rate that use of the Secured Overnight Financing Rate is subject to important limitations and disclaimers, including that the New York Federal Reserve may alter the methods of calculation, publication schedule, rate revision practices or availability of the Secured Overnight Financing Rate at any time without notice.

Each U.S. Government Securities Business Day (as defined under “Description of the Notes”), the New York Federal Reserve publishes the Secured Overnight Financing Rate on its website at approximately 8:00 A.M., New York City time. If errors are discovered in the transaction data provided by The Bank of New York Mellon or DTCC Solutions LLC, or in the calculation process, subsequent to the initial publication of the Secured Overnight Financing Rate but on that same day, the Secured Overnight Financing Rate and the accompanying summary statistics may be republished at approximately 2:30 P.M., New York City time. Additionally, if transaction data from The Bank of New York Mellon or DTCC Solutions LLC had previously not been available in time for publication, but became available later in the day, the affected rate or rates may be republished at around this time. Rate revisions will only be effected on the same day as initial publication and will only be republished if the change in the rate exceeds one basis point. Any time a rate is revised, a footnote to the New York Federal Reserve’s publication would indicate the revision. This revision threshold will be reviewed periodically by the New York Federal Reserve and may be changed based on market conditions.

As the Secured Overnight Financing Rate is published by the New York Federal Reserve based on data received from other sources, we have no control over its determination, calculation or publication. There can be no guarantee that the Secured Overnight Financing Rate will not be discontinued or fundamentally altered in a manner that is materially adverse to the interests of investors in the SNP 2028 Floating Rate Notes. The interest rate for any Interest Period will not be adjusted for any modifications or amendments to the SOFR Index or the Secured Overnight Financing Rate data that the New York Federal Reserve may publish after the interest rate for such Interest Period has been determined. If the manner in which the Secured Overnight Financing Rate is calculated is changed, that change may result in a reduction of the amount of interest payable on the SNP 2028 Floating Rate Notes and the trading prices of the SNP 2028 Floating Rate Notes.

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CAPITALIZATION OF THE GROUP

The following table sets forth the Group’s indebtedness and capitalization as of December 31, 2023, included in the Group’s audited consolidated financial statements as of December 31, 2023, in accordance with IFRS-IASB on an actual basis and as adjusted to reflect the issuance of the Notes (converting the principal amount of the Notes into euros at the European Central Bank reference rate for euro at December 29, 2023, of $1.105 per €1.00).

This table should be read in conjunction with the Group’s audited consolidated financial statements as of December 31, 2023, the notes related thereto and the financial and operating data incorporated by reference into this prospectus supplement and the accompanying prospectus. This table does not reflect the Concurrent Offering.

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DESCRIPTION OF THE NOTES

The following is a summary of certain terms of the Notes. It supplements the description of the general terms of the debt securities we may issue contained in the accompanying prospectus under the heading “Description of Debt Securities.” If there is any inconsistency between the following summary and the description in the accompanying prospectus, the following summary governs.

Certain Defined Terms

The following terms have the following meanings:

“Amounts Due” are the principal amount of, premium, if any, together with any accrued but unpaid interest, and Additional Amounts, if any, due on the Notes. References to such amounts will include amounts that have become due and payable, but which have not been paid, prior to the exercise of the Bail-in Power by the Relevant Resolution Authority.

“Applicable Banking Regulations” means at any time the laws, regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, then applicable to Banco Santander and/or the Group including, without limitation to the generality of the foregoing, the CRD IV, the BRRD, the SRM Regulation and those regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency of the Regulator then applicable to Banco Santander and/or the Group including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, in each case to the extent then in effect in the Kingdom of Spain (whether or not such regulations, requirements, guidelines or policies have the force of law and whether or not they are applied generally or specifically to Banco Santander and/or the Group).

“Bail-in Power” means any power existing from time to time under, and exercised in compliance with, any laws, regulations, rules or requirements in effect in the Kingdom of Spain, relating to (i) the transposition of the BRRD, including its article 48 and, when applicable, its article 59 (therefore, the write-down capital conversion power at the point of non-viability) (including but not limited to, Law 11/2015, RD 1012/2015 and any other implementing regulations), (ii) the SRM Regulation and (iii) the instruments, rules or standards created thereunder, pursuant to which any obligation of a Regulated Entity (or an affiliate of such Regulated Entity) can be reduced, cancelled, suspended, modified, or converted into shares, other securities, or other obligations of such Regulated Entity (or affiliate of such Regulated Entity).

“BRRD” means Directive 2014/59/EU of 15 May establishing a framework for the recovery and resolution of credit institutions and investment firms or such other directive as may come into effect in place thereof, as amended or replaced from time to time.

“Calculation Agent” means the Trustee (as defined herein) or such other person authorized by Banco Santander as the party responsible for calculating the rate(s) of interest and interest amount(s) and/or such other amount(s) from time to time in relation to the Notes of any series, as applicable.

“CET1 Capital” means at any time, the common equity tier 1 capital of Banco Santander or the Group, respectively, as calculated in accordance with Chapter 2 (Common Equity Tier 1 Capital) of Title I (Elements of own funds) of Part Two (Own Funds and Eligible Liabilities) of the CRR and/or Applicable Banking Regulations at such time, including any applicable transitional, phasing in or similar provisions.

“Common Equity Tier 1 Instruments” means instruments qualifying as CET1 Capital.

“CRD IV” means any or any combination of the CRD IV Directive, the CRR, and any CRD IV Implementing Measures.

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“CRD IV Directive” means Directive 2013/36/EU of the European Parliament and of the Council of 26 June 2013 on access to the activity of credit institutions and the prudential supervision of credit institutions and investment firms or such other directive as may come into effect in place thereof, as amended or replaced from time to time.

“CRD IV Implementing Measures” means any regulatory capital rules implementing the CRD IV Directive or the CRR which may from time to time be introduced, including, but not limited to, delegated or implementing acts (regulatory technical standards) adopted by the European Commission, national laws and regulations, and regulations and guidelines issued by the Regulator, the European Banking Authority or any other relevant authority, which are applicable to Banco Santander (on a standalone basis) or the Group (on a consolidated basis) and which prescribe the requirements to be fulfilled by financial instruments for inclusion in the regulatory capital or the minimum requirement for own funds and eligible liabilities, as the case may be, of Banco Santander (on a standalone basis) or the Group (on a consolidated basis).

“CRR” means Regulation (EU) No. 575/2013 of the European Parliament and of the Council of 26 June 2013 on the prudential requirements for credit institutions and investment firms or such other regulation as may come into effect in place thereof, as amended or replaced from time to time.

“Law 11/2015” means Law 11/2015 of 18 June, on recovery and resolution of credit institutions and investment firms (Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión), as amended or replaced from time to time.

“MREL” means the “minimum requirement for own funds and eligible liabilities” for credit institutions under the BRRD, set in accordance with Article 45 of the BRRD (as transposed in the Kingdom of Spain), Commission Delegated Regulation (EU) No. 2016/1450 of 23 May 2016, supplementing Directive 2014/59/EU of the European Parliament and of the Council with regard to regulatory technical standards specifying the criteria relating to the methodology for setting the minimum requirement for own funds and eligible liabilities and any other Applicable Banking Regulations.

“RD 1012/2015” means Royal Decree 1012/2015, of 6 November, implementing Law 11/2015, of 18 June, on the recovery and resolution of credit institutions and investment firms (Real Decreto 1012/2015, de 6 de noviembre, por el que se desarrolla la Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión), as amended or replaced from time to time.

“Regulated Entity” means any entity to which BRRD, as implemented in the Kingdom of Spain (including but not limited to, Law 11/2015, RD 1012/2015 and any other implementing regulations), or any other Spanish law relating to the Bail-in Power, applies, which includes, certain credit institutions, investment firms, and certain of their parent or holding companies.

“Regulator” means the European Central Bank, the Bank of Spain, the Relevant Resolution Authority or such other or successor authority exercising primary bank supervisory authority or the role of primary bank resolution authority, in each case with respect to prudential or resolution matters in relation to Banco Santander and/or the Group.

“Relevant Resolution Authority” means the Spanish Fund for the Orderly Restructuring of Banks, the Bank of Spain, the European Single Resolution Board, as the case may be, according to Law 11/2015, and any other entity with the authority to exercise the Bail-in Power or any other resolution power from time to time.

“Senior Higher Priority Liabilities” means the unsubordinated and unsecured obligations (créditos ordinarios) of Banco Santander, other than the Senior Non Preferred Liabilities.

“Senior Non Preferred Liabilities” means any unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander under Additional Provision 14.2 of Law

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11/2015 (including the Notes) and any other obligations which, by law and/or by their terms, and to the extent permitted by Spanish law, rank pari passu with the Senior Non Preferred Liabilities.

“Spanish Insolvency Law” means the restated text of the Spanish Insolvency Law (Ley Concursal) approved by the Royal Decree-Legislative 1/2020, of 5 May, as amended or replaced from time to time.

“SRM Regulation” means Regulation (EU) No. 806/2014 of the European Parliament and of the Council of 15 July 2014, establishing uniform rules and a uniform procedure for the resolution of credit institutions and certain investment firms in the framework of a Single Resolution Mechanism and a Single Resolution Fund, as amended or replaced from time to time.

“Supervisory Permission” means, in relation to any action, such supervisory permission (or, as appropriate, waiver) from the Regulator as is required therefor under Applicable Banking Regulations.

“TLAC” means the “total loss-absorbing capacity” requirement for global systemically important institutions under the CRR, set in accordance with Article 92a of the CRR and/or any other Applicable Banking Regulations.

The Notes

The SNP 2028 Floating Rate Notes

The Senior Non Preferred Callable Floating Rate Notes due 2028 (the “SNP 2028 Floating Rate Notes”) will be issued in an initial aggregate principal amount of $    and will mature on March    , 2028. From and including the date of issuance, which is expected to be March    , 2024, interest for each Interest Period (as defined herein) will accrue on the SNP 2028 Floating Rate Notes at a rate per annum equal to Compounded SOFR (as defined herein) plus a margin of    basis points, subject to a minimum interest rate of 0%. Interest will be payable quarterly in arrears on March    , June    , September    , and December    of each year (each a “Floating Interest Payment Date”), commencing on June    , 2024, up to and including March    , 2028 (the “SNP 2028 Floating Rate Notes Maturity Date”) or any date of earlier redemption; provided, that if any scheduled Floating Interest Payment Date, other than the scheduled SNP 2028 Floating Rate Notes Maturity Date or date of redemption or repayment, would fall on a day that is not a Business Day, that Floating Interest Payment Date will be postponed to the next succeeding Business Day, except that if that Business Day falls in the next succeeding calendar month, the Floating Interest Payment Date will be the immediately preceding Business Day. If the SNP 2028 Floating Rate Notes Maturity Date or date of redemption or repayment is not a Business Day, we will pay any interest and principal and/or any amount payable upon redemption of the SNP 2028 Floating Rate Notes, as applicable, on the next succeeding Business Day, but such final Floating Interest Payment Date will not be postponed and interest on that payment will not accrue from and after the SNP 2028 Floating Rate Notes Maturity Date or date of redemption or repayment. Interest on the SNP 2028 Floating Rate Notes shall be determined five (5) U.S. Government Securities Business Days (as defined herein) before each Floating Interest Payment Date. Interest will be paid to holders of record of the SNP 2028 Floating Rate Notes in respect of the principal amount thereof outstanding as of the close of business 15 calendar days preceding the relevant Floating Interest Payment Date, whether or not a Business Day.

Each interest period on the SNP 2028 Floating Rate Notes will begin on (and include) a Floating Interest Payment Date (or, in the case of the first interest period, March    , 2024) and end on (but exclude) the following Floating Interest Payment Date, or, in the case of the final interest period, the SNP 2028 Floating Rate Notes Maturity Date (each an “Interest Period”).

As further set forth herein, the amount of interest accrued and payable on the SNP 2028 Floating Rate Notes for each Interest Period will be equal to the product of (i) the outstanding principal amount of the SNP 2028 Floating Rate Notes multiplied by (ii) the product of (a) the interest rate for the relevant Interest Period multiplied by (b) the quotient of the actual number of calendar days in such Interest Period divided by 360.

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The interest rate on the SNP 2028 Floating Rate Notes for each Interest Period will be equal to Compounded SOFR plus a margin of    basis points, subject to a minimum interest rate of 0%.

“Compounded SOFR,” which is a compounded average of daily SOFR, will be determined by the Calculation Agent in respect of any Interest Period in accordance with the following formula, with the resulting percentage being rounded, if necessary, to the fifth decimal place, with 0.000005 being rounded upwards:

Where:

“d” means, in respect of the relevant Observation Period, the number of calendar days in such Observation Period;

“d₀” means, in respect of any Observation Period, the number of U.S. Government Securities Business Days in the relevant Observation Period;

“_i” means a series of whole numbers from one to d₀, each representing the relevant U.S. Government Securities Business Days in chronological order from, and including, the first U.S. Government Securities Business Day in the relevant Observation Period;

“n_i” means, in respect of any U.S. Government Securities Business Day_i, in the relevant Observation Period the number of calendar days from, and including, such U.S. Government Securities Business Day_i up to, but excluding, the following U.S. Government Securities Business Day; and

“SOFR_i” means, in respect of any U.S. Government Securities Business Day_i in the relevant Observation Period, the SOFR in respect of such U.S. Government Securities Business Day.

“Observation Period” means, in respect of an Interest Period, the period from, and including, the date falling the number of Observation Shift Days (as defined herein) prior to the first day of such Interest Period and ending on, but excluding, the date that is the number of Observation Shift Days prior to the Floating Interest Payment Date for such Interest Period.

“Observation Shift Days” means five (5) U.S. Government Securities Business Days.

“SOFR” means the rate determined by the Calculation Agent in respect of a U.S. Government Securities Business Day, in accordance with the following provisions:

(i) the Secured Overnight Financing Rate published for such U.S. Government Securities Business Day as such rate appears on the SOFR Administrator’s Website (as defined herein) at 3:00 p.m. (New York time) on the immediately following U.S. Government Securities Business Day (the “SOFR Determination Time”);

(ii) if the rate specified in (i) above does not so appear, the Secured Overnight Financing Rate as published in respect of the first preceding U.S. Government Securities Business Day for which the Secured Overnight Financing Rate was published on the SOFR Administrator’s Website;

where:

“SOFR Administrator” means the Federal Reserve Bank of New York (or a successor administrator of the Secured Overnight Financing Rate); and

“SOFR Administrator’s Website” means the website of the Federal Reserve Bank of New York, or any successor source.

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“U.S. Government Securities Business Day” means any day except for a Saturday, Sunday or a day on which the Securities Industry and Financial Markets Association (SIFMA) recommends that the fixed income departments of its members be closed for the entire day for purposes of trading in U.S. government securities.

Notwithstanding anything to the contrary herein, if we or our designee determine on or prior to the relevant SOFR Determination Time that a Benchmark Transition Event (as defined herein) and its related Benchmark Replacement Date (as such terms are defined herein) have occurred with respect to Compounded SOFR, then the provisions set forth under “Effect of Benchmark Transition Event” below will thereafter apply to all determinations of the rate of interest payable on the SNP 2028 Floating Rate Notes.

For the avoidance of doubt, in accordance with the benchmark replacement provisions, after a Benchmark Transition Event and its related Benchmark Replacement Date have occurred, the interest payable for each Interest Period on the SNP 2028 Floating Rate Notes will be an annual rate equal to the sum of the Benchmark Replacement (as defined herein) and the applicable margin.

Effect of Benchmark Transition Event

If we or our designee determine on or prior to the relevant Reference Time (as defined herein) that a Benchmark Transition Event and its related Benchmark Replacement Date have occurred in respect of the then-current Benchmark, the Benchmark Replacement will replace the then-current Benchmark for all purposes relating to the SNP 2028 Floating Rate Notes in respect of all determinations on such date and all determinations on all subsequent dates.

In connection with the implementation of a Benchmark Replacement, we or our designee will have the right to make Benchmark Replacement Conforming Changes (as defined herein) from time to time.

No such change shall affect the Trustee’s or the Calculation Agent’s own rights, duties or immunities under the First Supplemental Indenture (as defined herein), the calculation agency agreement or otherwise without their consent.

Any determination, decision, election or calculation that may be made by us or our designee pursuant to the provisions set forth in this section, including any determination with respect to a rate or adjustment or of the occurrence or non-occurrence of an event, circumstance or date and any decision to take or refrain from taking any action or any selection, will be conclusive and binding absent manifest error, will be made in our or our designee’s sole discretion, and, notwithstanding anything to the contrary in the documentation relating to the notes, shall become effective without consent from the holders of the SNP 2028 Floating Rate Notes or any other party.

In no event shall the Calculation Agent, the Trustee or any paying agent be responsible for making any such determination, decision, election or calculation; or have any responsibility to determine whether any manifest error has occurred, and, in the absence of notice from us, may conclusively assume that no manifest error exists and shall suffer no liability in so assuming.

None of the Trustee, any paying agent or the Calculation Agent (unless we are acting in such capacity) shall be under any obligation to: (i) monitor, determine or verify the unavailability or cessation of Compounded SOFR or SOFR, or whether or when there has occurred, or to give notice to any other transaction party of the occurrence of, any Benchmark Transition Event or related Benchmark Replacement Date, (ii) select, determine or designate any Benchmark Replacement, or other successor or replacement benchmark index, or whether any conditions to the designation of such a rate or index have been satisfied, (iii) select, determine or designate any Benchmark Replacement Adjustment, or other modifier to any replacement or successor index, or (iv) determine whether or what Benchmark Replacement Conforming Changes are necessary or advisable, if any, in connection with any of the foregoing, including, but not limited to, adjustments as to any alternative spread thereon, the business day convention, interest determination dates or any other relevant methodology applicable to such substitute or successor benchmark.

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For the avoidance of doubt, in no event shall the Trustee, any paying agent or the Calculation Agent be required to act as our designee for the purposes of determining if any Benchmark Transition Event has occurred, selecting any Benchmark Replacement or determining any Benchmark Replacement Adjustment unless such Trustee, paying agent or Calculation Agent agrees to such appointment in writing.

In connection with the foregoing, each of the Trustee, the paying agent and the Calculation Agent shall be entitled to rely conclusively on any determinations made by us or our designee without independent investigation, and none will have any liability for actions taken at our direction in connection therewith.

None of the Trustee, the paying agent or the Calculation Agent shall be liable for any inability, failure or delay on its part to perform any of its duties set forth in this prospectus supplement as a result of the unavailability of SOFR, Compounded SOFR or other applicable Benchmark Replacement, including as a result of any failure, inability, delay, error or inaccuracy on the part of any other transaction party in providing any direction, instruction, notice or information required or contemplated by the terms of this prospectus supplement and reasonably required for the performance of such duties. None of the Trustee, the paying agent or the Calculation Agent shall be responsible or liable for our actions or omissions or for those of our designee, or for any failure or delay in the performance by us or our designee, nor shall any of the Trustee, the paying agent or the Calculation Agent be under any obligation to oversee or monitor our performance or that of our designee.

Certain Defined Terms

As used herein:

“Benchmark” means, initially, Compounded SOFR, as such term is defined above; provided that if we or our designee determine on or prior to the Reference Time that a Benchmark Transition Event and its related Benchmark Replacement Date have occurred with respect to Compounded SOFR (or the published daily SOFR used in the calculation thereof) or the then-current Benchmark, then “Benchmark” means the applicable Benchmark Replacement.

“Benchmark Replacement” means the first alternative set forth in the order below that can be determined by us or our designee as of the Benchmark Replacement Date:

(1) the sum of: (a) the alternate rate of interest that has been selected or recommended by the Relevant Governmental Body (as defined herein) as the replacement for the then-current Benchmark for the applicable Corresponding Tenor (as defined herein) and (b) the Benchmark Replacement Adjustment;

(2) the sum of: (a) the ISDA Fallback Rate (as defined herein) and (b) the Benchmark Replacement Adjustment; or

(3) the sum of: (a) the alternate rate of interest that has been selected by us or our designee as the replacement for the then-current Benchmark for the applicable Corresponding Tenor giving due consideration to any industry-accepted rate of interest as a replacement for the then-current Benchmark for U.S. dollar denominated floating rate notes at such time and (b) the Benchmark Replacement Adjustment.

“Benchmark Replacement Adjustment” means the first alternative set forth in the order below that can be determined by us or our designee as of the Benchmark Replacement Date:

(1) the spread adjustment, or method for calculating or determining such spread adjustment (which may be a positive or negative value or zero) that has been selected or recommended by the Relevant Governmental Body for the applicable Unadjusted Benchmark Replacement (as defined herein);

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(2) if the applicable Unadjusted Benchmark Replacement is equivalent to the ISDA Fallback Rate, then the ISDA Fallback Adjustment (as defined herein); or

(3) the spread adjustment (which may be a positive or negative value or zero) that has been selected by us or our designee giving due consideration to any industry-accepted spread adjustment, or method for calculating or determining such spread adjustment, for the replacement of the then-current Benchmark with the applicable Unadjusted Benchmark Replacement for U.S. dollar denominated floating rate notes at such time.

For the avoidance of doubt, the Benchmark Replacement Adjustment for the applicable Benchmark Replacement Date may be selected, recommended or determined on a day other than such Benchmark Replacement Date.

“Benchmark Replacement Conforming Changes” means, with respect to any Benchmark Replacement, any technical, administrative or operational changes (including changes to the definitions of “Interest Period” and “Observation Period”, timing and frequency of determining rates and making payments of interest, rounding of amounts or tenors, and other administrative matters) that we or our designee decide may be appropriate to reflect the adoption of such Benchmark Replacement in a manner substantially consistent with market practice (or, if we or our designee decide that adoption of any portion of such market practice is not administratively feasible or if we or our designee determine that no market practice for use of the Benchmark Replacement exists, in such other manner as we or our designee determine is reasonably necessary).

“Benchmark Replacement Date” means the earliest to occur of the following events with respect to the then-current Benchmark (including the daily published component used in the calculation thereof):

(1) in the case of clause (1) or (2) of the definition of “Benchmark Transition Event,” the later of (a) the date of the public statement or publication of information referenced therein and (b) the date on which the administrator of the Benchmark permanently or indefinitely ceases to provide the Benchmark (or such component); or

(2) in the case of clause (3) of the definition of “Benchmark Transition Event,” the date of the public statement or publication of information referenced therein.

For the avoidance of doubt, if the event giving rise to the Benchmark Replacement Date occurs on the same day as, but earlier than, the Reference Time in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for such determination.

“Benchmark Transition Event” means the occurrence of one or more of the following events with respect to the then-current Benchmark (including the daily published component used in the calculation thereof):

(1) a public statement or publication of information by or on behalf of the administrator of the Benchmark (or such component) announcing that such administrator has ceased or will cease to provide the Benchmark (or such component), permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the Benchmark (or such component);

(2) a public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark (or such component), the central bank for the currency of the Benchmark (or such component), an insolvency official with jurisdiction over the administrator for the Benchmark (or such component), a resolution authority with jurisdiction over the administrator for the Benchmark (or such component) or a court or an entity with similar insolvency or resolution authority over the administrator for the Benchmark (or such component), which states that the administrator of the Benchmark (or such component) has ceased or will cease to provide the

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Benchmark (or such component) permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide the Benchmark (or such component); or

(3) a public statement or publication of information by the regulatory supervisor for the administrator of the Benchmark announcing that the Benchmark is no longer representative.

“Corresponding Tenor” with respect to a Benchmark Replacement means a tenor (including overnight) having approximately the same length (disregarding business day adjustment) as the applicable tenor for the then-current Benchmark.

“ISDA Definitions” means the 2006 ISDA Definitions published by the International Swaps and Derivatives Association, Inc. or any successor thereto, as amended or supplemented from time to time, or any successor definitional booklet for interest rate derivatives published from time to time.

“ISDA Fallback Adjustment” means the spread adjustment, which may be a positive or negative value or zero, that would apply for derivatives transactions referencing the ISDA Definitions to be determined upon the occurrence of an index cessation event with respect to the Benchmark for the applicable tenor.

“ISDA Fallback Rate” means the rate that would apply for derivatives transactions referencing the ISDA Definitions to be effective upon the occurrence of an index cessation date with respect to the Benchmark for the applicable tenor excluding the applicable ISDA Fallback Adjustment.

“Reference Time” with respect to any determination of the Benchmark means (1) if the Benchmark is Compounded SOFR, the SOFR Determination Time, and (2) if the Benchmark is not Compounded SOFR, the time determined by us or our designee in accordance with the Benchmark Replacement Conforming Changes.

“Relevant Governmental Body” means the Federal Reserve Board and/or the Federal Reserve Bank of New York, or a committee officially endorsed or convened by the Federal Reserve Board and/or the Federal Reserve Bank of New York or any successor thereto.

“Unadjusted Benchmark Replacement” means the Benchmark Replacement excluding the Benchmark Replacement Adjustment.

The SNP 2028 Fixed-to-Fixed Rate Notes

The    % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2028 (the “SNP 2028 Fixed-to-Fixed Rate Notes”) will be issued in an initial aggregate principal amount of $     and will mature on March    , 2028 (the “SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date”). From (and including) the date of issuance, which is expected to be March    , 2024, to (but excluding) March    , 2027 (the “SNP 2028 Reset Date”), interest will accrue on the SNP 2028 Fixed-to-Fixed Rate Notes at a fixed rate of    % per annum. From (and including) the SNP 2028 Reset Date to (but excluding) the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date (the “SNP 2028 Reset Period”), interest will accrue on the SNP 2028 Fixed-to-Fixed Rate Notes at a fixed rate equal to the applicable U.S. Treasury Rate as of the second Business Day preceding the SNP 2028 Reset Date (the “SNP 2028 Reset Determination Date”), plus    % per annum.

Interest will be payable semi-annually in arrears on March  and September of each year (each a “2028 Fixed Interest Payment Date”), commencing on September , 2024, up to and including the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date or any date of earlier redemption. Interest will be paid to holders of record of the SNP 2028 Fixed-to-Fixed Rate Notes in respect of the principal amount thereof outstanding as of the close of business 15 calendar days preceding the relevant 2028 Fixed Interest Payment Date, whether or not a Business Day.

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Interest on the SNP 2028 Fixed-to-Fixed Rate Notes will be calculated on the basis of a 360-day year consisting of twelve 30-day months and, in the case of an incomplete month, on the basis of the actual number of days elapsed in such month. If any scheduled 2028 Fixed Interest Payment Date is not a Business Day, we will pay interest on the next Business Day, but interest on that payment will not accrue during the period from and after the scheduled 2028 Fixed Interest Payment Date. If the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date or date of redemption or repayment is not a Business Day, we may pay interest and principal on the next succeeding Business Day, but interest on that payment will not accrue during the period from and after the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date or date of redemption or repayment.

The SNP 2030 Fixed-to-Fixed Rate Notes

The    % Senior Non Preferred Callable Fixed-to-Fixed Rate Notes due 2030 (the “SNP 2030 Fixed-to-Fixed Rate Notes”, and together with the SNP 2028 Floating Rate Notes and the SNP 2028 Fixed-to-Fixed Rate Notes, the “Notes”) will be issued in an initial aggregate principal amount of $     and will mature on March    , 2030 (the “SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date”, and each of the SNP 2028 Floating Rate Notes Maturity Date, the SNP 2028 Fixed-to-Fixed Rate Notes Maturity Date and the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date, a “Maturity Date”). From (and including) the date of issuance, which is expected to be March    , 2024, to (but excluding) March    , 2029 (the “SNP 2030 Reset Date”, and each of the SNP 2028 Reset Date and the SNP 2030 Reset Date, a “Reset Date”), interest will accrue on the SNP 2030 Fixed-to-Fixed Rate Notes at a fixed rate of    % per annum. From (and including) the SNP 2030 Reset Date to (but excluding) the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date (the “SNP 2030 Reset Period”, and each of the SNP 2028 Reset Period and the SNP 2030 Reset Period, a “Reset Period”), interest will accrue on the SNP 2030 Fixed-to-Fixed Rate Notes at a fixed rate equal to the applicable U.S. Treasury Rate as of the second Business Day preceding the SNP 2030 Reset Date (the “SNP 2030 Reset Determination Date”, and each of the SNP 2028 Reset Determination Date and the SNP 2030 Reset Determination Date, a “Reset Determination Date”), plus    % per annum.

Interest will be payable semi-annually in arrears on March and September of each year (each a “2030 Fixed Interest Payment Date”, and each Floating Interest Payment Date, 2028 Fixed Interest Payment Date and 2030 Fixed Interest Payment Date, an “Interest Payment Date”), commencing on September , 2024, up to and including the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date or any date of earlier redemption. Interest will be paid to holders of record of the SNP 2030 Fixed-to-Fixed Rate Notes in respect of the principal amount thereof outstanding as of the close of business 15 calendar days preceding the relevant 2030 Fixed Interest Payment Date, whether or not a Business Day.

Interest on the SNP 2030 Fixed-to-Fixed Rate Notes will be calculated on the basis of a 360-day year consisting of twelve 30-day months and, in the case of an incomplete month, on the basis of the actual number of days elapsed in such month. If any scheduled 2030 Fixed Interest Payment Date is not a Business Day, we will pay interest on the next Business Day, but interest on that payment will not accrue during the period from and after the scheduled 2030 Fixed Interest Payment Date. If the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date or date of redemption or repayment is not a Business Day, we may pay interest and principal on the next succeeding Business Day, but interest on that payment will not accrue during the period from and after the SNP 2030 Fixed-to-Fixed Rate Notes Maturity Date or date of redemption or repayment.

Certain Provisions Relating to the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes

The “U.S. Treasury Rate” means, in relation to a Reset Date and the Reset Period commencing on such Reset Date, the rate per annum equal to: (1) the average of the yields on actively traded U.S. Treasury securities adjusted to constant maturity, for one-year maturities for the five (5) Business Days immediately prior to the relevant Reset Determination Date, published in the most recent H.15, for the maturity of one year; or (2) if such release (or any successor release) is not published during the week immediately prior to the relevant Reset

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Determination Date or does not contain such yields, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for the relevant Reset Date.

The U.S. Treasury Rate shall be determined by the Calculation Agent.

If the U.S. Treasury Rate cannot be determined, for whatever reason, as set forth under (1) or (2) above, “U.S. Treasury Rate” means the rate in percentage per annum as notified by the Calculation Agent to Banco Santander equal to the yield on U.S. Treasury securities having a maturity of one year as set forth in the most recent H.15 (or any successor release to be determined by Banco Santander and notified to the Calculation Agent) at 5:00 p.m. (New York City time) on the relevant Reset Determination Date.

“Comparable Treasury Issue” means, with respect to a Reset Period, the U.S. Treasury security or securities selected by Banco Santander (and notified to the Calculation Agent) with a maturity date on or about the last day of the relevant Reset Period, and that would be utilized at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities denominated in U.S. dollars and having a maturity of one year.

“Comparable Treasury Price” means, with respect to a Reset Date, (i) the arithmetic average of the Reference Treasury Dealer Quotations (as defined herein) for the Reset Date (calculated on the relevant Reset Determination Date preceding such Reset Date), after excluding the highest and lowest such Reference Treasury Dealer Quotations, or (ii) if fewer than five such Reference Treasury Dealer Quotations are received, the arithmetic average of all such quotations, or (iii) if fewer than two such Reference Treasury Dealer Quotations are received, then such Reference Treasury Dealer Quotation as quoted in writing to Banco Santander and the Calculation Agent by a Reference Treasury Dealer.

“H.15” means the daily statistical release designated as such and published by the Board of Governors of the United States Federal Reserve System under the caption “Treasury constant maturities,” or any successor or replacement publication as determined by Banco Santander (and notified to the Calculation Agent) that establishes yield on actively traded U.S. Treasury securities adjusted to constant maturity, and “most recent H.15” means, in respect of a Reset Period, the H.15 which includes a yield to maturity for U.S. Treasury securities with a maturity of one year published closest in time but prior to the relevant Reset Determination Date.

“Reference Treasury Dealer” means each of up to five banks selected by Banco Santander, or the affiliates of such banks, which are (i) primary U.S. Treasury securities dealers, and their respective successors, or (ii) market makers in pricing corporate bond issues denominated in U.S. dollars.

“Reference Treasury Dealer Quotations” means with respect to each Reference Treasury Dealer and a Reset Date, the arithmetic average, as determined by the Calculation Agent, of the bid and offered prices for the applicable Comparable Treasury Issue, expressed in each case as a percentage of its principal amount, at 11:00 a.m. (New York City time), on the relevant Reset Determination Date.

General

The Notes will constitute three separate series of senior non preferred debt securities issued pursuant to the provisions of an indenture to be dated as of the date of issuance of the Notes (the “Base Indenture”) between us as Issuer and The Bank of New York Mellon, London Branch, as trustee (the “Trustee”), as amended and supplemented by a first supplemental indenture to be dated as of the date of issuance of the Notes (the “First Supplemental Indenture”) between us as Issuer and the Trustee.

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Book-entry interests in the Notes will be issued in denominations of $200,000 and integral multiples of $200,000 in excess thereof.

With respect to the Notes, the term “Business Day” means any day, other than Saturday or Sunday, that is not a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York or London nor a day when the T2 real-time gross settlement (RTGS) system, owned and operated by the Eurosystem, or any successor thereto, is closed for business.

The principal corporate trust office of the Trustee in London, United Kingdom, is designated as the principal paying agent. We may at any time designate additional paying agents or rescind the designation of paying agents or approve a change in the office through which any paying agent acts.

We will issue the Notes in fully registered form. The Notes of each series will be represented by one or more global securities deposited with a custodian for, and registered in the name of a nominee of, DTC. You may hold a beneficial interest in the Notes through DTC and its participants, including Euroclear and Clearstream Luxembourg. The Underwriters expect to deliver the Notes through the facilities of DTC on or about March    , 2024. For a more detailed summary of the form of the Notes and settlement and clearance arrangements, you should read “Description of Certain Provisions Relating to the Debt Securities and Contingent Convertible Capital Securities—Form of Securities; Book-Entry System” in the accompanying prospectus. Indirect holders trading their beneficial interests in the Notes through DTC must trade in DTC’s same-day funds settlement system and pay in immediately available funds. Secondary market trading will occur in the ordinary way following the applicable rules and operating procedures of Euroclear and Clearstream Luxembourg.

Definitive debt securities will only be issued in limited circumstances set forth under “Description of Certain Provisions Relating to the Debt Securities and Contingent Convertible Capital Securities—Form of Securities; Book-Entry System” in the accompanying prospectus.

Payment of principal of and interest on the Notes, so long as the Notes are represented by global securities, will be made in immediately available funds. Beneficial interests in the global securities will trade in the same-day funds settlement system of DTC, and secondary market trading activity in such interests will therefore settle in same-day funds.

Status of the Notes

The payment obligations of Banco Santander in respect of principal under the Notes constitute direct, unconditional, unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander and, in accordance with Additional Provision 14.2 of Law 11/2015, but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, such payment obligations rank (i) pari passu among themselves and with any other Senior Non Preferred Liabilities, (ii) junior to the Senior Higher Priority Liabilities (and, accordingly, upon the insolvency of Banco Santander, the payment obligations of Banco Santander in respect of principal under the Notes will be met after payment in full of the Senior Higher Priority Liabilities) and (iii) senior to any present and future subordinated obligations (créditos subordinados) of Banco Santander in accordance with Article 281 of the Spanish Insolvency Law.

Claims of holders of the Notes in respect of interest accrued but unpaid as of the commencement of any insolvency procedure in respect of Banco Santander shall constitute subordinated claims (créditos subordinados) against Banco Santander ranking in accordance with the provisions of Article 281.1.3º of the Spanish Insolvency Law and no further interest shall accrue from the date of the declaration of insolvency of Banco Santander.

The obligations of Banco Santander under the Notes are subject to the Bail-in Power.

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As of December 31, 2023, Banco Santander had outstanding €69.099 billion of unsubordinated indebtedness, including €38.470 billion of Senior Higher Priority Liabilities and €30.629 billion of Senior Non Preferred Liabilities (including the senior non preferred debt securities issued by Banco Santander prior to the entrance into force of Royal Decree-Law 11/2017).

Additionally, as of December 31, 2023, Banco Santander had outstanding €25.205 billion of secured indebtedness and €24.214 billion of subordinated indebtedness. Banco Santander subsidiaries had €87.673 billion indebtedness outstanding as of December 31, 2023.

Additional Amounts

All amounts payable (whether in respect of principal, redemption amount, interest or otherwise) in respect of the Notes will be made free and clear of and without withholding or deduction for or on account of any present or future taxes, duties, assessments or governmental charges (collectively, “Taxes”) of whatever nature imposed or levied by or on behalf of the Kingdom of Spain or any political subdivision thereof or any authority or agency therein or thereof having power to tax, unless the withholding or deduction of such Taxes is required by law. In the event any withholding or deduction is imposed or levied in respect of any payment of interest by or on behalf of the Kingdom of Spain or any political subdivision thereof or any authority or agency therein or thereof having power to tax, Banco Santander shall pay such additional amounts (“Additional Amounts”) as will result in receipt by the holders of the Notes of the amount of interest which would have been received by them had no such withholding or deduction been required. No Additional Amounts will be paid with respect to payments of principal or any premium.

However, Banco Santander shall not be required to pay any Additional Amounts in respect of any Notes:

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Additional Amounts will also not be paid with respect to any payment to a holder who is a fiduciary, a partnership, a limited liability company or person other than the sole beneficial owner of that payment, to the extent that payment would be required by the laws of Spain (or any political subdivision thereof) to be included in the income, for tax purposes, of a beneficiary or settlor with respect to the fiduciary, a member of that partnership, an interest holder in that limited liability company or a beneficial owner who would not have been entitled to the Additional Amounts had it been the holder.

For the purposes of (iv) above, the “Relevant Date” means, in respect of any payment, the date on which such payment first becomes due and payable, but if the full amount of the moneys payable has not been received by the Trustee on or prior to such due date, it means the first date on which, the full amount of such moneys having been so received and being available for payment to holders of the Notes, notice to that effect shall have been duly given to the holders of the relevant series of Notes in accordance with the Base Indenture.

Any reference in this “Additional Amounts” section to “principal” shall include any redemption amounts and any other amounts in the nature of principal payable pursuant to the Base Indenture as amended and supplemented by the First Supplemental Indenture, and “interest” shall include all amounts referred to as interest in this prospectus supplement and the Base Indenture as supplemented by the First Supplemental Indenture.

Except where the context requires otherwise, any reference in this prospectus supplement and the accompanying prospectus to interest on a Note shall be deemed to include any Additional Amounts payable with respect thereto.

Redemption and Repurchase

Early Redemption for Taxation Reasons

If as a result of any change in, or amendment to, the laws or regulations of Spain or of any political subdivision thereof or any authority or agency therein or thereof having power to tax or in the interpretation or administration of any such laws or regulations which becomes effective on or after the date of issue of the Notes of the relevant series, Banco Santander shall determine that (a) Banco Santander would be required to pay Additional Amounts as set forth under “—Additional Amounts” or (b) Banco Santander would not be entitled to claim a deduction in computing tax liabilities in Spain in respect of any interest to be paid on the next Interest Payment Date on the Notes of the relevant series or the value of such deduction to Banco Santander would be materially reduced or (c) the applicable tax treatment of the Notes of the relevant series changes in a material way that was not reasonably foreseeable at the issue date, Banco Santander may, at its option and having given no less than five (5) nor more than 30 days’ notice (ending, in the case of the SNP 2028 Floating Rate Notes, on a Floating Interest Payment Date) to the holders of the Notes of the relevant series in accordance with the terms set forth under “Description of Debt Securities—Notices” in the accompanying prospectus (which notice shall be irrevocable) and a concurrent copy thereof to the Trustee, redeem in whole, but not in part, the outstanding Notes of the relevant series, in accordance with the requirements of Applicable Banking Regulations in force at the

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relevant time, at their early tax redemption amount, which shall be their principal amount, together with any accrued interest thereon to (but excluding) the date fixed for redemption; provided, however, that (i) in the case of (a) above, no such notice of redemption may be given earlier than 90 days (or, in the case of the SNP 2028 Floating Rate Notes, a number of days which is equal to the aggregate of the number of days falling within the then current Interest Period plus 60 days) prior to the earliest date on which Banco Santander would be obliged to pay such Additional Amounts were a payment in respect of the Notes of the relevant series then due and (ii) redemption for taxation reasons may only take place in accordance with Applicable Banking Regulations (including, without limitation, in accordance with Articles 77 and 78a of the CRR) in force at the relevant time and subject to Banco Santander obtaining Supervisory Permission therefor, if and as required.

Early Redemption for a TLAC/MREL Disqualification Event

See “Description of Debt Securities—Redemption and Repurchase—Early Redemption of Senior Debt Securities for a TLAC/MREL Disqualification Event” in the accompanying prospectus.

Optional Redemption

Banco Santander may redeem (i) the SNP 2028 Floating Rate Notes, at its option, in whole, but not in part, on March    , 2027, (ii) the SNP 2028 Fixed-to-Fixed Rate Notes, at its option, in whole, but not in part, on March    , 2027, and/or (iii) the SNP 2030 Fixed-to-Fixed Rate Notes, at its option, in whole, but not in part, on March    , 2029; in each case at their respective principal amount, together with any accrued and unpaid interest thereon to (but excluding) the date fixed for redemption, having given not less than five (5) nor more than 30 days’ notice to the holders of the SNP 2028 Floating Rate Notes, the SNP 2028 Fixed-to-Fixed Rate Notes and/or the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable, in accordance with the terms set forth under “Description of Debt Securities—Notices” in the accompanying prospectus (which notice shall be irrevocable and shall specify the date for redemption) and a concurrent copy thereof to the Trustee.

The optional redemption of the SNP 2028 Floating Rate Notes, the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes, at the option of Banco Santander, is subject to Banco Santander obtaining prior Supervisory Permission, if and as required under Applicable Banking Regulations, and may only take place in accordance with Applicable Banking Regulations (including, without limitation, in accordance with Articles 77 and 78a of the CRR) in force at the relevant time.

No Additional Redemption Events

Other than as set forth under (i) “—Early Redemption for Taxation Reasons”, (ii) “Description of Debt Securities—Redemption and Repurchase—Early Redemption of Senior Debt Securities for a TLAC/MREL Disqualification Event” in the accompanying prospectus and (iii) “—Optional Redemption”, Banco Santander may not redeem the Notes of any series.

Notice of Redemption

See “Description of Debt Securities—Redemption and Repurchase—Notice of Redemption” in the accompanying prospectus.

Repurchase of Notes

Banco Santander and any of its subsidiaries or any third party designated by any of them, may only purchase Notes of any series in the open market or otherwise and at any price in accordance with Applicable Banking Regulations (including, without limitation, in accordance with Articles 77 and 78a of the CRR) in force at the relevant time and will be subject to Supervisory Permission, as required.

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Events of Default and Defaults; Limitation of Remedies

If any of the following events occurs and is continuing with respect to the Notes of any series, it shall constitute an Event of Default with respect to the Notes of such series (an “Event of Default”):

Under the terms of the Base Indenture, as amended and supplemented by the First Supplemental Indenture, no exercise of a resolution tool or resolution power by the Relevant Resolution Authority or any action in compliance therewith shall constitute an Event of Default.

If an Event of Default with respect to the Notes of any series occurs as set forth in paragraph (i) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the Notes of that series may institute proceedings for the winding up or liquidation of Banco Santander but may take no further action in respect of such default.

If an Event of Default with respect to the Notes of any series occurs as set forth in paragraph (ii) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the Notes of that series may declare the Notes of such series immediately due and payable whereupon the Notes of such series shall, when permitted by applicable Spanish Insolvency Law, become immediately due and payable at their early termination amount (which shall be their principal amount, together with all interest (if any) accrued and unpaid thereon).

Without prejudice to paragraphs (i) and (ii) above, the Trustee or the holders of at least 25% in outstanding principal amount of the Notes of any series may at their discretion and without further notice, institute such proceedings against Banco Santander as they may think fit to enforce any obligation, condition or provision binding on Banco Santander under the Notes of such series, provided that, except as provided in paragraph (ii) winding up above, Banco Santander shall not as a consequence of such proceedings be obliged to pay any sum or sums representing or measured by reference to principal or interest in respect of the Notes of such series sooner than the same would otherwise have been payable by it or any damages.

Notwithstanding any contrary provisions, nothing shall impair the right of a holder, absent the holder’s consent, to sue for any payments due but unpaid with respect to the Notes of any series.

Events of Default and Defaults - General

See “Description of Debt Securities—Events of Default and Defaults; Limitation of Remedies—Events of Default and Defaults - General” in the accompanying prospectus.

Substitution of Issuer

See “Description of Debt Securities—Events of Default and Defaults; Limitation of Remedies—Substitution of Issuer” in the accompanying prospectus.

Waiver of Right of Set-off

Subject to applicable law, neither any holder or beneficial owner of the Notes of any series nor the Trustee acting on behalf of the holders of the Notes of such series may exercise, claim or plead any right of set-off,

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netting, compensation or retention in respect of any amount owed to it by Banco Santander in respect of, or arising under, or in connection with, the Notes of such series or the Base Indenture as amended and supplemented by the First Supplemental Indenture, and each holder and beneficial owner of the Notes of such series, by virtue of its holding of any Notes of such series or any interest therein, and the Trustee acting on behalf of such holders, shall be deemed to have waived all such rights of set-off, netting, compensation or retention. If, notwithstanding the above, any amounts due and payable to any holder or beneficial owner of a Note of any series or any interest therein by Banco Santander in respect of, or arising under, the Notes of such series are discharged by set-off, such holder or beneficial owner shall, subject to applicable law, immediately pay an amount equal to the amount of such discharge to Banco Santander (or, if the event of any voluntary or involuntary liquidation of Banco Santander shall have occurred, the liquidator or administrator of Banco Santander, as the case may be) and, until such time as payment is made, shall hold an amount equal to such amount in trust (where possible) or otherwise for Banco Santander (or the liquidator or administrator of Banco Santander, as the case may be) and, accordingly, any such discharge shall be deemed not to have taken place.

Listing

We intend to apply for the listing of the Notes on the New York Stock Exchange in accordance with its rules.

Governing Law

The Base Indenture, the First Supplemental Indenture and the Notes will be governed by and construed in accordance with the laws of the State of New York, except that the authorization and execution by Banco Santander of the Base Indenture, the First Supplemental Indenture and the Notes, and certain provisions of the Notes, the Base Indenture and the First Supplemental Indenture related to the ranking of the Notes, shall be governed by and construed in accordance with Spanish law.

Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power

Notwithstanding any other term of the Notes or any other agreements, arrangements, or understandings between Banco Santander and any holder of the Notes, by its acquisition of the Notes, each holder (which, for the purposes of this clause, includes each holder of a beneficial interest in the Notes) acknowledges, accepts, consents to and agrees:

(i) to be bound by the effect of the exercise of the Bail-in Power by the Relevant Resolution Authority, which may include and result in any of the following, or some combination thereof:

(ii) that the terms of the Notes are subject to, and may be varied, if necessary, to give effect to, the exercise of the Bail-in Power by the Relevant Resolution Authority.

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Each holder of the Notes also acknowledges and agrees that the foregoing description of the Bail-in Power and its exercise is exhaustive on the matters set forth herein to the exclusion of any other agreements, arrangements or understandings relating to the application of any Bail-in Power to the Notes.

See “Description of Debt Securities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power” in the accompanying prospectus.

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TAXATION

Spanish Taxation

The following discussion supplements or supersedes, as applicable, the description of material Spanish tax considerations contained in the accompanying prospectus under the heading “Taxation” that are relevant to the Notes. If there is any inconsistency between the following discussion and the description in the accompanying prospectus, the following discussion governs.

The following is a general description of material Spanish tax considerations relating to the holders who are the beneficial owners of the securities (the “holders,” the “investors,” the “purchasers” or the “shareholders,” as the case may be). It does not purport to be a complete analysis of all tax considerations relating to these securities.

Prospective investors should consult their own tax advisors as to the consequences under the tax laws of the country of which they are resident for tax purposes and the tax laws of Spain of acquiring, holding and disposing of securities and receiving any payments under the securities. The information contained within this section is based upon the law as in effect on the date of this document and is subject to any change in law that may take effect after such date (which may have retroactive effects). Investors should consider the legislative changes which could occur in the future.

This analysis is a general description of the tax treatment under the currently in force Spanish legislation applicable in the common territory of Spain and, hence, it does not describe the regional tax regimes in the Historical Territories of the Basque Country and the Community of Navarre or the provisions passed by Autonomous Regions (Comunidades Autónomas) which may apply to investors for certain taxes.

In addition, investors should note that the appointment by an investor in securities or any person through which an investor holds securities, of a custodian, collection agent or similar person in relation to such securities in any jurisdiction may have tax implications. Investors should consult their own tax advisors in relation to the tax consequences for them of any such appointment.

Introduction

This information has been prepared in accordance with the following Spanish tax legislation in force at the date of this document:

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A. TAXATION IN SPAIN OF DEBT SECURITIES

1. Individuals with Tax Residency in Spain

Both interest payments periodically received and income derived from the transfer, redemption or repayment of the debt securities constitute a return on investment obtained from the transfer of a person’s own capital to third parties in accordance with the provisions of Section 25 of the IIT Law, and therefore must be included in the investor’s IIT savings taxable base pursuant to the provisions of the aforementioned law and as from 2023 be generally taxed at a flat rate of 19% on the first EUR 6,000; 21% from EUR 6,000.01 up to EUR 50,000; 23% from EUR 50,000.01 up to EUR 200,000; 27% from EUR 200,000.01 up to EUR 300,000; or 28% for any amount in excess of EUR 300,000.

Income from the transfer of the debt securities must be computed as the difference between the amounts obtained in the transfer, redemption or reimbursement of the debt securities and their acquisition or subscription value. Costs and expenses effectively borne on the acquisition and/or disposal of the debt securities must be taken into account, insofar as adequately evidenced, in calculating the income. When calculating the net income, expenses related to the management and deposit of the debt securities will be deductible, excluding those pertaining to discretionary or individual portfolio management.

According to Section 44.5 of Royal Decree 1065/2007 (which applies to preferred securities and debt instruments issued under Law 10/2014 and which have been originally registered with entities that manage clearing systems located outside Spain, provided that these entities are recognized by Spanish law or by the law of another Organization for Economic Cooperation and Development country such as DTC, Euroclear and/or Clearstream Luxembourg), Banco Santander will pay interest without withholding to individual holders who are resident for tax purposes in Spain provided that the information regarding the debt securities required by Exhibit 99.1 to the registration statement of which this prospectus supplement forms a part is submitted by the relevant paying agent, notwithstanding the information obligations of Banco Santander under general provisions of Spanish tax legislation. In addition, income obtained upon redemption or repayment by Banco Santander of the debt securities may also be paid without withholding on account of IIT under the same conditions.

If those requirements are not met, such interest and income derived from any transfer of the debt securities may be subject to withholding on account of IIT at the then-applicable rate (currently set at 19%).

Furthermore, in the case of debt securities held by Spanish resident individuals and deposited with a Spanish resident entity acting as depositary or custodian, payments of interest or income obtained upon redemption or repayment by Banco Santander of the debt securities may be subject to withholding tax on account of IIT at the then-applicable general rate (currently set at 19%) which will be made by the depositary or custodian. Any amounts withheld on account of IIT may be credited against the final IIT liability for the relevant tax year and may be refundable pursuant to Section 103 of the IIT Law.

According to Net Wealth Tax regulations (subject to any exceptions provided under relevant legislation in an Autonomous Region), the net worth of individuals with tax residency in Spain up to the amount of EUR 700,000

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is exempt from Net Wealth Tax. Therefore, holders should take into account the value of any debt securities which they hold as at 31 December each year. The applicable marginal rates range between 0.2% and 3.5%, although the final tax rates may vary depending on any applicable regional tax laws, and some reductions may apply.

In addition, the solidarity provisional wealth tax for high-net-worth individuals (the so-called “Solidarity Tax”) was approved in December 2022 by the Solidarity Tax Law. The Solidarity Tax is a direct and personal tax that complements the Net Wealth Tax in which the taxable event is a natural person’s ownership of at least EUR 3,000,000 in net assets on 31 December of each year.

The taxpayers of the Solidarity Tax and the Net Wealth Tax are individuals. In practice, as the Solidarity Tax Law allows the Net Wealth Tax amount payable to be deducted, the Solidarity Tax generally has a greater impact on taxpayers residing in Autonomous Regions in which the Net Wealth Tax is not paid. The rates of the Solidarity Tax are (i) 1.7% on a net worth between EUR 3,000,000 and EUR 5,347,998.03, (ii) 2.1% on a net worth between EUR 5,347,998.03 and EUR 10,695,996.06 and (iii) 3.5% on a net worth of more than EUR 10,695,996.06.

Although the Solidarity Tax was initially designed to be temporary, its application has been indefinitely extended, pursuant to the Fifth Additional Provision of Royal Decree-Law 8/2023 of 27 December adopting measures to deal with the economic and social consequences of the conflicts in Ukraine and the Middle East and to alleviate the effects of the drought (Real Decreto-ley 8/2023, de 27 de diciembre, por el que se adoptan medidas para afrontar las consecuencias económicas y sociales derivadas de los conflictos en Ucrania y Oriente Próximo, así como para paliar los efectos de la sequía), until a revision of Spanish wealth taxation takes place in the context of a reform of the Spanish regional financing system.

Prospective investors are advised to seek their own professional advice in relation to the Net Wealth Tax and the Solidarity Tax.

Individuals resident in Spain for tax purposes who acquire ownership or other rights over any debt securities by inheritance, gift or legacy will be subject to the Spanish Inheritance and Gift Tax in accordance with the applicable Spanish regional and State rules. Although the tax rate ranges between 7.65% and 34%, the effective tax rates range between 0% and 81.6% depending on relevant factors (such as the amount of the gift or inheritance, the net wealth of the heir or beneficiary of the gift, and the kinship with the deceased or the donor). Some tax benefits could reduce the effective tax rate. In addition, the final tax rate may vary depending also on the legislation of the corresponding Autonomous Region.

2. Legal Entities with Tax Residency in Spain

See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—2.1. Corporate Income Tax (Impuesto sobre Sociedades)” in the accompanying prospectus.

See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—2.2. Net Wealth Tax (Impuesto sobre el Patrimonio) and Solidarity Tax (Impuesto Temporal de Solidaridad de las Grandes Fortunas)” in the accompanying prospectus.

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See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—2.3 Inheritance and Gift Tax (Impuesto sobre Sucesiones y Donaciones)” in the accompanying prospectus.

3. Individuals and Legal Entities with no tax residency in Spain

This section analyzes the tax treatment applicable to holders who are non-resident for tax purposes in Spanish territory and are beneficial owners of the debt securities. Non-resident holders are individuals who are not IIT taxpayers and entities non-resident in Spanish territory, pursuant to Article 6 of the NRIT Law.

The tax regime described herein is general in nature, and the specific circumstances of each taxpayer should be considered in the light of the applicable double taxation treaties.

See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—3.1 Non-resident Income Tax (Impuesto sobre la renta de No Residentes)” in the accompanying prospectus.

Individuals resident in a country with which Spain has entered into a treaty for the avoidance of double taxation (“DTT”) in relation to Net Wealth Tax would generally not be subject to such tax. Otherwise, non-Spanish resident individuals whose properties and rights are located in Spain, or that can be exercised within the Spanish territory, exceed EUR 700,000 on the last day of any given year would be subject to Net Wealth Tax. The applicable rates currently range between 0.2% and 3.5%. The U.S. – Spain Income Tax Treaty (the “Treaty”) does not address Net Wealth Tax. Individuals who are non-resident in Spain for tax purposes may apply the rules approved by the Autonomous Region where the assets and rights with more value (i) are located, (ii) can be exercised or (iii) must be fulfilled.

In addition, the Solidarity Tax was approved in December 2022 by the Solidarity Tax Law. The Solidarity Tax is a direct and personal tax that complements the Net Wealth Tax in which the taxable event is a natural person’s ownership of at least EUR 3,000,000 in net assets on 31 December of each year.

The taxpayers of the Solidarity Tax and the Net Wealth Tax are individuals. In practice, as the Solidarity Tax Law allows the Net Wealth Tax amount payable to be deducted, the Solidarity Tax generally has a greater impact on taxpayers who apply the rules approved by an Autonomous Region in which the Net Wealth Tax is not paid. The rates of the Solidarity Tax are (i) 1.7% on a net worth between EUR 3,000,000 and EUR 5,347,998.03, (ii) 2.1% on a net worth between EUR 5,347,998.03 and EUR 10,695,996.06 and (iii) 3.5% on a net worth of more than EUR 10,695,996.06.

Although the Solidarity Tax was initially designed to be temporary, its application has been indefinitely extended, pursuant to the Fifth Additional Provision of Royal Decree-Law 8/2023 of 27 December adopting measures to deal with the economic and social consequences of the conflicts in Ukraine and the Middle East and to alleviate the effects of the drought (Real Decreto-ley 8/2023, de 27 de diciembre, por el que se adoptan medidas para afrontar las consecuencias económicas y sociales derivadas de los conflictos en Ucrania y Oriente Próximo, así como para paliar los efectos de la sequía), until a revision of Spanish wealth taxation takes place in the context of a reform of the Spanish regional financing system.

However, non-Spanish resident individuals will be exempt from Net Wealth Tax and Solidarity Tax in respect of the debt securities to the extent that the income deriving from the debt securities is exempt from NRIT as described in “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—3.1 Non-resident Income Tax (Impuesto sobre la renta de No Residentes)” in the accompanying prospectus.

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Non-Spanish resident legal entities are not subject to Net Wealth Tax nor to the Solidarity Tax.

Prospective investors are advised to seek their own professional advice in relation to the Net Wealth Tax and the Solidarity Tax.

Individuals not resident in Spain for tax purposes who acquire ownership or other rights over debt securities by inheritance, gift or legacy, will be subject to the Spanish Inheritance and Gift Tax in accordance with the applicable Spanish regional and state rules, unless they reside in a country for tax purposes with which Spain has entered into a DTT in relation to Inheritance and Gift Tax. In such case, the provisions of the relevant DTT will apply. The U.S. and Spain have not entered into a DTT in relation to Inheritance and Gift Tax.

If no DTT in relation to Inheritance Gift Tax applies, individuals who are non-resident in Spain for tax purposes will be subject to Inheritance and Gift Tax in accordance with Spanish legislation, to the extent that rights deriving from the debt securities (i) are located, (ii) can be exercised or (iii) must be fulfilled within Spanish territory.

If either the deceased or the donee is not resident in Spain for tax purposes, the applicable rules will be those corresponding to the relevant Spanish Autonomous Region in accordance with the law. As such, prospective investors should consult their tax advisors.

Although the tax rate ranges between 7.65% and 34%, the effective tax rates range between 0% and 81.6% depending on relevant factors (including the legislation of the corresponding Autonomous Region). Some tax benefits could reduce the effective tax rate.

Legal entities not resident in Spain for tax purposes which acquire ownership or other rights over the debt securities by inheritance, gift or legacy are not subject to the Spanish Inheritance and Gift Tax. Such acquisitions will be subject to NRIT (as described above), except as provided in any applicable DTT entered into by Spain. In general, DTTs provide for the taxation of this type of income solely in the country of tax residence of the holder of the debt securities.

4. Tax Rules for debt securities not Listed on a regulated market, a multilateral trading facility or an organized market

If the Notes are not listed on a regulated market, a multilateral trading facility or an organized market in an OECD country on any payment date, interest or income from the redemption or repayment obtained by holders will be subject to withholding tax at the then-applicable general rate (currently set at 19% on account of IIT, CIT or NRIT, as applicable), except in the case of holders who are: (a) resident in a Member State of the EU (other than Spain) or in a Member State of the European Economic Area (other than Spain) which has entered into an effective exchange of tax information agreement with Spain, and obtain the income either directly or through a permanent establishment located in another Member State of the EU (other than Spain) or in a Member State of the EEA (other than Spain) which has entered into an effective exchange of tax information agreement with Spain, provided that such holders (i) do not obtain the income on the Notes through a permanent establishment in Spain or in a country or jurisdiction which is not a Member State of the EU or a Member State of the EEA which has entered into an effective exchange of tax information agreement with Spain and (ii) are not resident of, or are not located in, nor obtain income through, a non-cooperative jurisdiction for Spanish tax purposes (in the terms of the First Additional Provision of Law 36/2006, of 29 November, on prevention measures and actions against tax fraud, as amended through Law 11/2021, of 9 July, and as amended, complemented and restated from time to time) or through a Member State of the EEA not having an effective exchange of tax information agreement with

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Spain in force; or (b) Spanish financial entities which comply with the requirements established in Article 61.c), or Spanish securitization funds which comply with the requirements established in Article 61.k), of the Corporate Income Tax Regulations approved by Royal Decree 634/2015, of 10 July 2015, or non-Spanish financial entities acting through a Spanish branch which comply with the requirements established in Article 8.1 of the Non-Resident Income Tax Regulations approved by Royal Decree 1776/2004, of 30 July 2004; or (c) resident for tax purposes of a country which has entered into a DTT with Spain which provides for an exemption from Spanish tax or a reduced withholding tax rate with respect to interest payable to any holder, who is fully entitled to the benefits of such DTT, provided that, in the case of holders referred to in sections (a) and (c), each holder delivers to the Issuer, as soon as reasonably practicable but before any payment is due or made (whichever comes first) a valid certificate of tax residence (or the specific form required under the relevant DTT, as applicable) duly issued by the competent tax authorities of its country of tax residence evidencing such holder as resident for tax purposes in that country and accrediting such holder as tax resident in the relevant jurisdiction within the meaning of the relevant DTT, issued not more than 12 months prior to the date on which the relevant amount is due or paid (whichever comes first). For the avoidance of doubt, if the certificate of tax residence refers to a specific tax period it will only deemed to be valid in relation with payments made during the referred tax period.

See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—2. Legal Entities with Tax Residency in Spain—2.2 Net Wealth Tax (Impuesto sobre el Patrimonio) and Solidarity Tax (Impuesto Temporal de Solidaridad de las Grandes Fortunas)” and “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—3. Individuals and Legal Entities with no tax residency in Spain—3.2 Net Wealth Tax (Impuesto sobre el Patrimonio) and Solidarity Tax (Impuesto Temporal de Solidaridad de las Grandes Fortunas)” above or in the accompanying prospectus (when applicable).

5. Information about the debt securities in connection with payments

See “Taxation—Spanish Taxation—A. Taxation in Spain of debt securities—5. Information about the debt securities in connection with payments” in the accompanying prospectus.

6. Indirect taxation

The acquisition and any subsequent transfer of the debt securities will be exempt from indirect taxes in Spain, i.e., exempt from Transfer Tax, Stamp Duty and Value Added Tax, in accordance with Article 338 of Law 38/2022, of 27 December, of the Spanish Securities Markets and Investment Services (Ley 6/2023, de 17 de marzo, de los Mercados de Valores y de los Servicios de Inversión) and related provisions.

E. SPANISH FTT

See “Taxation—Spanish Taxation—E. Spanish FTT” in the accompanying prospectus.

U.S. Federal Income Tax Considerations

See the section of the accompanying prospectus entitled “Taxation—U.S. Federal Income Tax Considerations—Taxation of Debt Securities” for a discussion of the U.S. federal income tax consequences of the ownership and disposition of the Notes to the U.S. Holders described therein, as supplemented or superseded by the following discussion.

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Characterization of the Notes

The following discussion supplements the discussion in the accompanying prospectus under the caption “Taxation—U.S. Federal Income Tax Considerations—Taxation of Debt Securities” solely as it relates to the Notes offered hereby.

SNP 2028 Floating Rate Notes. The SNP 2028 Floating Rate Notes should be treated as “variable rate debt instruments” for U.S. federal income tax purposes and are not expected to be issued with original issue discount (“OID”).

SNP 2028 Fixed-to-Fixed Rate Notes and SNP 2030 Fixed-to-Fixed Rate Notes. Although the matter is not free from doubt, the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes should be treated as “variable rate debt instruments” that provide for stated interest at a single fixed rate followed by a qualified floating rate (“QFR”) for U.S. federal income tax purposes. Under the Treasury regulations applicable to variable rate debt instruments, in order to determine the amount of OID, if any, in respect of the SNP 2028 Fixed-to-Fixed Rate Notes or the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable, an equivalent fixed rate debt instrument must be constructed. The equivalent fixed rate debt instrument is constructed in the following manner: (i) first, the initial fixed rate is converted to a QFR that would preserve the fair market value of the SNP 2028 Fixed-to-Fixed Rate Notes or the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable, and (ii) second, each QFR (including the QFR determined under clause (i) above) is converted to a fixed rate substitute (which generally will be the value of that QFR as of the issue date of the SNP 2028 Fixed-to-Fixed Rate Notes or the SNP 2030 Fixed-to-Fixed Rate Notes, as applicable). Under the applicable Treasury Regulations, the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes generally will be treated as providing for “qualified stated interest” at a rate equal to the lowest rate of interest in effect at any time under the equivalent fixed rate debt instrument for such series of Notes, and any interest under the equivalent fixed rate debt instrument in excess of that rate generally would be treated as part of the stated redemption price at maturity and, therefore, as possibly giving rise to OID. Based on the application of these rules to the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes, and the expected pricing terms of the SNP 2028 Fixed-to-Fixed Rate Notes and the SNP 2030 Fixed-to-Fixed Rate Notes, respectively, we do not expect either the SNP 2028 Fixed-to-Fixed Rate Notes or the SNP 2030 Fixed-to-Fixed Rate Notes to be treated as issued with OID.

If, contrary to our expectation, any series of Notes is issued with OID, the rules described in “Taxation—U.S. Federal Income Tax Considerations—Taxation of Debt Securities—Original Issue Discount” in the accompanying prospectus would apply to such series of Notes.

Sale, Retirement or Other Taxable Disposition of the Notes

The following discussion supersedes and replaces, solely insofar as it relates to the Notes offered hereby, the third paragraph of the discussion under the heading “Taxation—U.S. Federal Income Tax Considerations—Taxation of Debt Securities—Sale, Retirement or Other Taxable Disposition of the Debt Securities” in the accompanying prospectus, and should be read in conjunction with the discussion under the heading “Taxation—U.S. Federal Income Tax Considerations—Taxation of Debt Securities” as if it appeared therein.

If any Spanish tax is imposed on a disposition of a Note, Treasury regulations generally provide that the tax will not be creditable against a U.S. Holder’s U.S. federal income tax liability. However, the Internal Revenue Service released notices that indicate that the Treasury Department and the Internal Revenue Service are considering amendments to these Treasury regulations and provide relief from certain of their provisions for taxable years ending before the date that a notice or other guidance withdrawing or modifying the temporary relief is issued (or any later date specified in such notice or other guidance). However, because any gain from dispositions of debt securities will generally be U.S. source, even if these Treasury regulations will not deny a U.S. Holder’s right to claim foreign tax credit with respect to Spanish taxes on disposition gains, other limitations

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under the foreign tax credit rules may preclude a U.S. Holder from claiming a foreign tax credit with respect to these taxes, if any. If a U.S. Holder is precluded from claiming a foreign tax credit, it is possible that the Spanish tax may either be deductible or reduce the amount realized on the disposition. U.S. Holders should consult their tax advisors regarding the creditability or deductibility of any Spanish tax on disposition gains in their particular circumstances, including any applicable limitations.

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UNDERWRITING (CONFLICTS OF INTEREST)

We and Barclays Capital Inc., Deutsche Bank Securities Inc., HSBC Securities (USA) Inc., J.P. Morgan Securities LLC, Jefferies LLC, Morgan Stanley & Co. LLC, RBC Capital Markets, LLC, Santander US Capital Markets LLC, SG Americas Securities, LLC and TD Securities (USA) LLC (the “Representatives”), acting on behalf of the underwriters for the offering named below (the “Underwriters”) have entered into an underwriting agreement with respect to the Notes. Subject to certain terms and conditions, we have agreed to sell to the Underwriters and each of the Underwriters has severally, and not jointly, agreed to purchase the respective principal amounts of the Notes indicated opposite such Underwriter’s name in the following table.

The Underwriters have agreed, severally and not jointly, to purchase all of the Notes sold under their respective underwriting agreements if any are purchased and that the obligations of the Underwriters are subject to approval of legal matters by their counsel, including the validity of the Notes, and certain conditions precedent such as the receipt by the Underwriters of officer’s certificates and legal opinions. The offering of the Notes by the Underwriters is subject to receipt and acceptance and the Underwriters have the right to reject any order in whole or in part.

We have agreed to indemnify the several Underwriters and their controlling persons against certain liabilities in connection with this offering, including liabilities under the Securities Act, or to contribute to payments the Underwriters may be required to make in respect of those liabilities.

Certain of the Underwriters are not broker-dealers registered with the SEC, and therefore may not make sales of any Notes in the United States or to U.S. persons except in compliance with applicable U.S. laws and regulations. To the extent any Underwriter that is not a U.S. registered broker-dealer intends to effect sales of Notes in the United States, it will do so through one or more U.S. registered broker-dealers or otherwise in accordance with the applicable U.S. securities laws and regulations.

Commissions and Discounts

The Underwriters propose to offer the Notes directly to the public at the public offering prices set forth on the cover page of this prospectus supplement. We estimate that the expenses of the offering payable by us, excluding the underwriting discount, will be approximately $      million. The Underwriters have agreed to reimburse us for approximately $      of such expenses.

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Matters Relating to the Initial Offering and Market-Making Resales

After the initial offering, the public offering prices or any other term of the offering may be changed.

The Notes will be offered in the United States through those Underwriters who are registered to offer the Notes for sale in the United States either directly or indirectly through their U.S. broker-dealer affiliates, or such other registered dealers as may be designated by the Underwriters. We intend to apply for the listing of the Notes on the New York Stock Exchange in accordance with its rules. The Notes are a new issue of securities with no established trading market. We have been advised by the Underwriters that the Underwriters, with the exception of Santander US Capital Markets LLC, intend to make a market in the Notes, but they are not obligated to do so and may discontinue market-making at any time without notice. No assurance can be given as to the liquidity of the trading market for the Notes. If an active trading market for the Notes does not develop, the market price and liquidity of the Notes may be adversely affected. If the Notes are traded, they may trade at a discount from their initial offering price, depending on prevailing interest rates, the market for similar securities, Banco Santander’s operating performance and financial condition, general economic conditions and other factors.

In this prospectus supplement, the term “the offering” means the initial offering of the Notes made in connection with their original issuance and not any subsequent resales of Notes in market-making transactions.

Settlement

The Notes will settle through the facilities of DTC and its direct and indirect participants (including Euroclear and Clearstream Luxembourg). The initial CUSIP number for the SNP 2028 Floating Rate Notes is    and the ISIN is     .. The initial CUSIP number for the SNP 2028 Fixed-to-Fixed Rate Notes is    and the ISIN is     . The initial CUSIP number for the SNP 2030 Fixed-to-Fixed Rate Notes is    and the ISIN is     .

It is expected that delivery of the Notes will be made against payment on or about March    , 2024, which will be the      New York business day following the date of pricing of the Notes (such settlement cycle being referred to as “T+ ”). Trades in the secondary market generally are required to settle in two business days, unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade Notes prior to two business days before the date of delivery of the Notes will be required, by virtue of the fact that the Notes initially will settle in T+ , to specify an alternate settlement cycle at the time of any such trade to prevent a failed settlement. Such purchasers should consult their own advisors.

No Sales of Similar Securities

From the date of this prospectus supplement, and continuing to and including March    , 2024, we have agreed that we will not, without the prior written consent of the Underwriters, offer, sell, contract to sell or otherwise dispose of, in the United States, any material amount of dollar-denominated debt securities issued or guaranteed by us which mature in more than one year and which are substantially similar to the Notes.

Stabilization Transactions and Short Sales

In connection with the offering, the Underwriters, with the exception of Santander US Capital Markets LLC, may purchase and sell Notes in the open market. These transactions may include short sales, stabilizing transactions and purchases to cover positions created by short sales. Short sales involve the sale by the Underwriters of a greater aggregate principal amount of Notes than they are required to purchase from us in the offering. Stabilizing transactions consist of certain bids or purchases made for the purpose of preventing or retarding a decline in the market price of the Notes while the offering is in progress.

The Underwriters may also impose a penalty bid. This occurs when a particular Underwriter repays to the Underwriters a portion of the underwriting discount received by it because the Underwriters have repurchased Notes sold by or for the account of such Underwriter in stabilizing or short-covering transactions.

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These activities by the Underwriters may stabilize, maintain or otherwise affect the market price of the Notes. As a result, the price of the Notes may be higher than the price that otherwise might exist in the open market. If these activities are commenced, they may be discontinued by the Underwriters at any time.

Other Relationships

The Underwriters and their respective affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. In the ordinary course of business, the Underwriters and their affiliates may have engaged in and may in the future engage in investment, financial, banking, hedging and advisory services with us or our affiliates, for which customary fees may apply.

In the ordinary course of their various business activities, the Underwriters (with the exception of Santander US Capital Markets LLC) and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investment and securities activities may involve securities and/or instruments of Banco Santander. Certain of the Underwriters or their affiliates that have a lending relationship with us routinely hedge, and certain other of those Underwriters or their affiliates may hedge, their credit exposure to us consistent with their customary risk management policies. Typically, such Underwriters and their affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the Notes offered hereby. Any such credit default swaps or short positions could adversely affect future trading prices of the Notes offered hereby. The Underwriters and their respective affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Certain of the Underwriters may resell notes outside of the United States to or through one or more of their affiliates.

Conflicts of Interest

Santander US Capital Markets LLC is a subsidiary of Banco Santander. Therefore, Santander US Capital Markets LLC is deemed to have a “conflict of interest” under FINRA Rule 5121 and, accordingly, the offering of the notes will comply with the applicable requirements of FINRA Rule 5121.

Pursuant to FINRA Rule 5121, a qualified independent underwriter is not required in connection with this offering because the notes to be offered are rated in one of the four highest generic rating categories by one of the nationally recognized statistical rating organizations. Santander US Capital Markets LLC will not confirm sales of the notes to any account over which it exercises discretionary authority without the specific written approval of the account holder.

Selling Restrictions

PRIIPs Regulation / Prohibition of Sales to EEA Retail Investors

The Notes which are the subject of the offering contemplated by this prospectus supplement are not offered, sold or otherwise made available to and will not be offered, sold or otherwise made available to any retail investor in the EEA. For the purposes of this provision

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Prohibition of Sales to UK Retail Investors

The Notes which are the subject of the offering contemplated by this prospectus supplement are not offered, sold or otherwise made available to and will not be offered, sold or otherwise made available to any retail investor in the UK. For the purposes of this provision

Notice to Prospective Investors in Spain

The Notes may not be offered, sold or distributed, nor may any subsequent resale of Notes be carried out in Spain, except in circumstances that do not require the registration of a prospectus in Spain or without complying with all legal and regulatory requirements under Spanish securities laws. No publicity or marketing of any kind shall be made in Spain in relation to the Notes.

Neither the Notes nor this prospectus supplement nor the accompanying prospectus have been registered with the Spanish National Securities Market Commission (Comisión Nacional del Mercado de Valores) (the “CNMV”), and therefore this prospectus supplement and the accompanying prospectus are not intended for any offer of the Notes in Spain that would require the registration of a prospectus with the CNMV.

Notice to Prospective Investors in Canada

This prospectus supplement and the accompanying prospectus constitute an “exempt offering document” as defined in and for the purposes of applicable Canadian securities laws. No prospectus has been filed with any securities commission or similar regulatory authority in Canada in connection with the offer and sale of the Notes. No securities commission or similar regulatory authority in Canada has reviewed or in any way passed upon this prospectus supplement and the accompanying prospectus or on the merits of the Notes and any representation to the contrary is an offense.

The Notes may be sold only to purchasers in the provinces of British Columbia, Ontario, Alberta, Québec, Nova Scotia, New Brunswick, Saskatchewan and Manitoba purchasing, or deemed to be purchasing, as principal

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that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions (“NI 45-106”) or subsection 73.3(1) of the Securities Act (Ontario) that were not created or used solely to purchase or hold securities as an accredited investor set forth in paragraph (m) or the definition of “accredited investor” in section 1.1 of NI 45-106 or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the Notes must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement and accompanying prospectus (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

We are relying on an exemption based on U.S. disclosure under section 3A.3 of National Instrument 33-105 Underwriting Conflicts from the requirement to provide disclosure with respect to “related issuer” or “connected issuer” relationships. Canadian investors should refer to the section entitled “Underwriting (Conflicts of Interest)” for further information.

The issuer is not a member institution of the Canada Deposit Insurance Corporation. The liability incurred by the issuer through the issuance and sale of the notes is not a deposit. The issuer is not regulated as a financial institution in Canada.

Upon receipt of this document, each Canadian investor hereby confirms that it has expressly requested that all documents evidencing or relating in any way to the sale of the securities set forth herein (including for greater certainty any purchase confirmation or any notice) be drawn up in the English language only. Par la réception de ce document, chaque investisseur canadien confirme par les présentes qu’il a expressément exigé que tous les documents faisant foi ou se rapportant de quelque manière que ce soit à la vente des valeurs mobilières décrites aux présentes (incluant, pour plus de certitude, toute confirmation d’achat ou tout avis) soient rédigés en anglais seulement.

Notice to Prospective Investors in the United Kingdom

Each Underwriter (a) has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the FSMA) received by it in connection with the issue or sale of the Notes in circumstances in which Section 21(1) of the FSMA does not or would not, if it was not an authorised person, apply to Banco Santander; and (b) has complied and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to the Notes in, from or otherwise involving the United Kingdom.

Notice to Prospective Investors in Hong Kong

(a) The Notes have not been offered or sold and will not be offered or sold in the Hong Kong by means of any document, any Notes other than (i) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571) of the laws of Hong Kong (the “SFO”) and any rules made under the SFO; or (ii) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32) of Hong Kong (the “C(WUMP)O”) or which do not constitute an offer to the public within the meaning of the C(WUMP)O; and (b) no advertisement, invitation or document relating to the Notes, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) has been or will be issued or has been or will be possessed for the purposes of the issue, whether in Hong Kong or elsewhere,

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other than with respect to the Notes which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the SFO and any rules made under the SFO.

Notice to Prospective Investors in Italy

The offering of the Notes has not been registered with the Commissione Nazionale per le Società e la Borsa (“CONSOB”) pursuant to Italian securities legislation and, accordingly, no Notes may be offered, sold or delivered, nor may copies of this prospectus supplement and the accompanying prospectus or any other document relating to the Notes be distributed in the Republic of Italy, except in accordance with any Italian securities, tax and other applicable laws and regulations.

Each Underwriter has represented and agreed that it has not offered, sold or delivered, and will not offer, sell or deliver any Notes or distribute any copy of this prospectus supplement and the accompanying prospectus or any other document relating to the Notes in Italy except:

Moreover, and subject to the foregoing, any such offer, sale or delivery of the Notes or distribution of copies of this prospectus supplement and the accompanying prospectus or any other document relating to the Notes in the Republic of Italy under (a) or (b) above must be:

Notice to Prospective Investors in Japan

The Notes have not been and will not be registered for a public offering in Japan pursuant to Article 4, Paragraph 1 of the Financial Instruments and Exchange Act of Japan (Act No. 25 of 1948, as amended (the “FIEA”)). Accordingly, the Notes may not be offered or sold directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to, or for the benefit of, a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the FIEA and any other applicable laws, regulations and ministerial guidelines of Japan in effect at the relevant time.

Notice to Prospective Investors in the People’s Republic of China (excluding Hong Kong, Macau and Taiwan)

The Notes are not being offered or sold and may not be offered or sold, directly or indirectly, in the People’s Republic of China, or the “PRC” (for such purposes, not including the Hong Kong and Macau Special

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Administrative Regions or Taiwan), except as permitted by all relevant laws and regulations of the PRC. The Notes are not an offer of securities within the meaning of the Securities Law of PRC or other pertinent laws and regulations of the PRC.

This prospectus supplement and the accompanying prospectus (i) have not been filed with or approved by the PRC authorities and (ii) do not constitute an offer to sell, or the solicitation of an offer to buy, any Notes in the PRC to any person to whom it is unlawful to make the offer or solicitation in the PRC.

The Notes may not be offered, sold or delivered to any person for reoffering or resale or redelivery, in any such case directly or indirectly (i) by means of any advertisement, invitation, document or activity which is directed at, or the contents of which are likely to be accessed or read by, the public in the PRC, or (ii) to any person within the PRC, other than in full compliance with all relevant laws and regulations of the PRC. Investors in the PRC are responsible for obtaining all relevant government and industry regulatory approvals/licenses, verification, filings and/ or registrations themselves, including, but not limited to, those which may be required by the China Securities Regulatory Commission, the State Administration of Foreign Exchange, the People’s Bank of China, the China Banking and Insurance Regulatory Commission and/or the Asset Management Association of China, and complying with all relevant PRC laws and regulations, including, but not limited to, all relevant foreign exchange regulations and/or securities investment regulations.

Notice to Prospective Investors in the Republic of Korea

This prospectus supplement and the accompanying prospectus are not, and under no circumstances are to be considered as, a public offering of securities in South Korea for the purposes of the Financial Investment Services and Capital Markets Act of Korea. The Notes have not been and will not be registered with the Financial Services Commission of South Korea for public offering in South Korea under the Financial Investment Services and Capital Markets Act and its subordinate decrees and regulations (collectively, the “FSCMA”). The Notes may not be offered, remarketed, sold or delivered, directly or indirectly, or offered, remarketed or sold to any person for re-offering or resale, directly or indirectly, in South Korea or to any resident of South Korea except as otherwise permitted under the applicable laws and regulations of South Korea, including the FSCMA and the Foreign Exchange Transaction Law and its subordinate decrees and regulations (collectively, the “FETL”). Without prejudice to the foregoing, the number of Notes offered in South Korea or to investors who are residents in South Korea shall be less than fifty and for a period of one year from the issue date of the Notes, none of the Notes may be divided resulting in an increased number of the Notes. Furthermore, the Notes may not be resold to South Korean residents unless the purchaser of the Notes complies with all applicable regulatory requirements (including but not limited to government reporting requirements under the FETL) in connection with the purchase of the Notes.

Notice to Prospective Investors in Taiwan

The Notes have not been and will not be registered with the Financial Supervisory Commission of Taiwan, pursuant to relevant securities laws and regulations and may not be offered or sold directly or indirectly in Taiwan, or to, or for the account or benefit of, any person in Taiwan unless otherwise in compliance with the applicable laws and regulations of Taiwan. No person or entity in Taiwan has been authorized to offer, sell, give advice regarding or otherwise intermediate the offering and sale of the Notes in Taiwan.

Notice to Prospective Investors in Singapore

This prospectus supplement and accompanying prospectus have not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and accompanying prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the Notes may not be circulated or distributed, nor may the Notes be offered or sold, or be made the subject of an invitation for subscription or purchase, nor may the Notes be circulated or distributed, whether directly or

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indirectly, to any person in Singapore other than (a) to an institutional investor (as defined in Section 4A of the Securities and Futures Act 2001 of Singapore, as modified or amended from time to time (the “SFA”)) pursuant to Section 274 of the SFA, (b) to an accredited investor (as defined in Section 4A of the SFA) pursuant to, and in accordance with the conditions specified in Section 275 of the SFA.

Notice to Prospective Investors in Switzerland

This prospectus supplement is not intended to constitute an offer or solicitation to purchase or invest in the Notes.

The Notes may not be publicly offered, directly or indirectly, in Switzerland within the meaning of the Swiss Financial Services Act (“FinSA”) and no application has or will be made to admit the Notes to trading on any trading venue (exchange or multilateral trading facility) in Switzerland. Neither this prospectus supplement nor any other offering or marketing material relating to the Notes constitutes a prospectus pursuant to the FinSA, and neither this prospectus supplement nor any other offering or marketing material relating to the Notes may be publicly distributed or otherwise made publicly available in Switzerland.

Notice to Prospective Investors in Australia

This prospectus supplement does not constitute a prospectus, a disclosure document or a product disclosure statement for the purposes of the Corporations Act 2001 (Cth) (“Corporations Act”) and does not purport to include all the information required for a prospectus, a disclosure document or a product disclosure statement under the Corporations Act. No prospectus, product disclosure statement or other disclosure document under Australian law has been lodged with the Australian Securities and Investments Commission in relation to the offering of the Notes.

The provision of this prospectus supplement to any person does not constitute an offer of, or an invitation to apply for, the Notes in Australia. Any offer in Australia of the Notes may only be made to persons who are “sophisticated investors” or “professional investors” within the meaning of sections 708(8) and (11) of the Corporations Act, respectively and who are a “wholesale client” within the meaning of section 761G of the Corporations Act. This prospectus supplement is not intended to be distributed or passed on, directly or indirectly, to any other class of persons in Australia.

Any person to whom the Notes are issued or sold must not offer for sale in Australia in the period of 12 months after the date of issue of the Notes except where disclosure to investors is not required under the Corporations Act or where the offer is made pursuant to a prospectus, disclosure document or product disclosure statement that complies with the Corporations Act. Any person acquiring the Notes must observe such Australian on-sale restrictions.

This prospectus supplement contains general information only and does not take into account the investment objectives, financial situation or particular needs of any particular person. It does not contain any securities recommendations or financial product advice. Before acting on the information contained in this prospectus supplement, investors should consider its appropriateness having regard to their investment objectives, financial situations and needs, and, if necessary, seek expert advice.

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LEGAL OPINIONS

Our U.S. counsel, Davis Polk & Wardwell LLP, will pass upon certain U.S. federal and New York legal matters relating to the validity of the Notes. Our Spanish counsel, Uría Menéndez Abogados, S.L.P., will pass upon certain Spanish legal matters for the Underwriters. Linklaters LLP will pass upon certain U.S. federal, New York and Spanish legal matters for the Underwriters.

EXPERTS

The consolidated financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus supplement by reference to the Annual Report on Form 20-F of Banco Santander, S.A. for the year ended December 31, 2023 have been so incorporated in reliance on the report of PricewaterhouseCoopers Auditores, S.L., an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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PROSPECTUS

Banco Santander, S.A.

By this prospectus we may offer —

DEBT SECURITIES

CONTINGENT CONVERTIBLE CAPITAL SECURITIES

ORDINARY SHARES

Banco Santander, S.A. may use this prospectus to offer from time to time senior preferred debt securities, senior non preferred debt securities, subordinated debt securities, contingent convertible capital securities and, solely in connection with the issuance of contingent convertible capital securities, ordinary shares (including in the form of American Depositary Shares). Banco Santander, S.A.’s American Depositary Shares, or ADSs, each representing the right to receive one share of capital stock of Banco Santander, S.A., are listed on the New York Stock Exchange under the symbol “SAN”. In addition, Banco Santander, S.A.’s ordinary shares are listed on the Madrid, Barcelona, Bilbao and Valencia stock exchanges (the “Spanish Stock Exchanges”) and quoted on the Automated Quotation System of the Spanish Stock Exchanges (the “Automated Quotation System”). Banco Santander, S.A.’s ordinary shares are also listed on the London (in the form of CREST Depository Interests), Warsaw and Mexico (on the Sistema Internacional de Cotizaciones of the Mexican Stock Exchange) stock exchanges.

This prospectus describes the general terms of these securities and the general manner in which we will offer these securities. We will provide the specific terms of any series of these securities, and the manner in which they will be offered, in one or more supplements to this prospectus. Any supplement may also add, update or change information contained, or incorporated by reference, into this prospectus. You should read this prospectus and the applicable prospectus supplement carefully before you invest in our securities.

You should read both this prospectus and the applicable prospectus supplement, together with the additional information described under the headings “Where You Can Find More Information” and “Incorporation of Documents by Reference”, before investing in any of the securities described in the prospectus. The amount and price of the offered securities will be determined at the time of the offering.

Investing in our securities involves risks. See “Risk Factors” beginning on page 7.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined that this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus may not be used to offer or sell any securities unless it is accompanied by a prospectus supplement.

The date of this prospectus is May 16, 2023.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form F-3 that we filed with the Securities and Exchange Commission (“SEC”) using a “shelf” registration or continuous offering process. Under this shelf process, we may sell the securities described in this prospectus in one or more offerings of an unspecified amount in one or more foreign currencies or currency units.

This prospectus provides you with a general description of the debt securities and contingent convertible capital securities (convertible into ordinary shares upon a trigger event) we may offer, which we will refer to collectively as the “securities”. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement will provide information regarding certain tax consequences of the purchase, ownership and disposition of the offered securities. The prospectus supplement may also add to, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and any prospectus supplement, you should rely on the information in that prospectus supplement. We will file each prospectus supplement with the SEC. You should read both this prospectus, the applicable prospectus supplement and any related issuer free writing prospectus, together with the additional information described under the headings “Where You Can Find More Information” and “Incorporation of Documents by Reference”.

The registration statement containing this prospectus, including exhibits to the registration statement, provides additional information about us and the securities offered under this prospectus. Statements contained in this prospectus and the applicable prospectus supplement about the provisions or content of any agreement or other document are only summaries. If SEC rules require that any agreement or document be filed as an exhibit to the registration statement, you should refer to that agreement or document for its complete contents. The registration statement can be read at the SEC’s offices or obtained from the SEC’s website mentioned under the heading “Where You Can Find More Information”.

Certain Terms

In this prospectus, the following terms will have the meanings set forth below, unless otherwise indicated or the context otherwise requires

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USE OF PROCEEDS

Unless we have disclosed a specific plan in the accompanying prospectus supplement, we will use the net proceeds from the sale of the securities offered by this prospectus for general corporate purposes. The Group has raised capital in various markets from time to time and we expect to continue to raise capital in appropriate markets as and when required.

BANCO SANTANDER, S.A.

Banco Santander, S.A. is the parent bank of the Group. The Group operates principally in Spain, the United Kingdom, other European countries, Brazil and other Latin American countries and the United States, offering a wide range of financial products. In Latin America, the Group has majority shareholdings in banks in Argentina, Brazil, Chile, Mexico, Peru, Colombia and Uruguay.

Banco Santander, S.A. was established on March 21, 1857 and incorporated in its present form by a public deed executed in Santander, Spain, on January 14, 1875. Banco Santander, S.A. is incorporated under, and governed by, the laws of the Kingdom of Spain as a company with unlimited duration and with limited liability (sociedad anónima).

Banco Santander, S.A. conducts business under the commercial name “Santander”. The Group’s principal corporate offices are located in Ciudad Grupo Santander, Avenida de Cantabria s/n, 28660 Boadilla del Monte, Madrid, Spain, and its telephone number is (011) 34-91-259-6520.

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SUMMARY OF RISK FACTORS

Investing in our securities involves risks. Prospective investors should consider carefully the risk factors incorporated by reference into this prospectus and the risk factors described in “Risk Factors” as well as the other information set out elsewhere in this prospectus (including any other documents incorporated by reference herein) and reach their own views prior to making any investment decision with respect to any of the securities described in this prospectus. The following list summarizes some, but not all, of these risks. Please read the information in the section entitled “Risk Factors” for a more thorough description of these and other risks:

Macro-economic and political risks

Risks relating to our business

Legal, regulatory and compliance risks for our business model

Credit risks

Operational and technology risks

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Liquidity and funding risks

Market risks

Risks related to our industry

Risk management

Model risk

General risks

Risks related to our industry

Reporting and control risks

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Foreign private issuer and other risks

Risks relating to the Securities

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RISK FACTORS

Prospective investors should consider carefully the risk factors incorporated by reference into this prospectus and as set out below as well as the other information set out elsewhere in this prospectus (including any other documents incorporated by reference herein) and reach their own views prior to making any investment decision with respect to any of the securities described in this prospectus.

Set out below and incorporated by reference herein are certain risk factors which could have a material adverse effect on Banco Santander’s and the Group’s business, operations, financial condition or prospects and cause future results to be materially different from expected results. Banco Santander’s results could also be affected by competition and other factors. These factors should not be regarded as a complete and comprehensive statement of all potential risks and uncertainties that Banco Santander and the Group face. Described are only those risks relating to Banco Santander’s and the Group’s operations or an investment in the securities that Banco Santander considers to be material. There may be additional risks that Banco Santander currently considers not to be material or of which they are not currently aware, and any of these risks could have the effects set forth below. All of these factors are contingencies which may or may not occur and Banco Santander is not in a position to express a view on the likelihood of any such contingency occurring. Investors should note that they bear Banco Santander’s and the Group’s solvency risk. Each of the risks highlighted below could have a material adverse effect on the amount of principal, interest, liquidation preference and distributions which investors will receive in respect of the securities. In addition, each of the highlighted risks could adversely affect the trading price of the securities or the rights of investors under the securities and, as a result, investors could lose some or all of their investment. Holders of contingent convertible capital securities or debt securities should consult their own financial, tax and legal advisers regarding the risks of an investment in the securities.

Capitalized terms and certain other terms used in this section “Risk Factors”, unless otherwise defined in this section, have the meanings assigned to them in “Description of Debt Securities” and “Description of Contingent Convertible Capital Securities” below.

Risks relating to Banco Santander and the Group

For a description of the risks associated with Banco Santander and the Group, see the section entitled “Risk Factors” of Banco Santander’s Annual Report on Form 20-F for the year ended December 31, 2022, which is incorporated by reference herein.

Risks Relating to our Business

Liquidity and funding risks are inherent in our business and could have a material adverse effect on us.

Liquidity risk is the risk that we either do not have sufficient financial resources available to meet our obligations as they are due, or we can only secure them at excessive cost. This risk is inherent in any banking business and can be heightened by a number of enterprise-specific factors, including over-reliance on a particular source of funding, changes in credit ratings or market-wide phenomena such as market dislocation, including as a result of the war in Ukraine or new outbreaks of the covid-19 pandemic. While we have in place liquidity management processes to mitigate and control these risks, as well as an organizational model based on autonomous subsidiaries in terms of capital and liquidity which limits the possibility of contagion between them, systemic market factors make it difficult to eliminate these risks completely. Constraints in the supply of liquidity, including in inter-bank lending, could materially and adversely affect the cost of funding of our business, and extreme liquidity constraints may affect our current operations and our ability to fulfil regulatory liquidity requirements, as well as limit growth possibilities.

Our cost of obtaining funding is directly related to prevailing interest rates and to our credit spreads. Increases in interest rates, such as those announced throughout 2022 by the ECB, the Bank of England and the

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Federal Reserve, and/or in our credit spreads could significantly increase the cost of our funding. Credit spreads variations are market-driven and may be influenced by market perceptions of our creditworthiness. Changes to interest rates and our credit spreads may occur frequently and could be unpredictable and highly volatile.

We rely, and will continue to rely, primarily on retail deposits to fund lending activities. The ongoing availability of this type of funding is sensitive to a variety of factors beyond our control, such as general economic conditions and the confidence of retail depositors in the economy and in the financial services industry, and the availability and extent of deposit guarantees, as well as competition for deposits between banks or with other products, such as mutual funds. Any of these factors could increase the amount of retail deposit withdrawals in a short period of time, thereby reducing our ability to access retail deposit funding on appropriate terms, or at all, in the future. If these circumstances were to arise, this could have a material adverse effect on our operating results, financial condition and prospects.

In March 2023, the liquidity issues faced by Silicon Valley Bank and other banks in the United States and the issues faced by the Swiss bank Credit Suisse, caused withdrawals of deposits from these banks and volatility in international markets. Central Banks took measures designed to guarantee the liquidity of the banking system. Although we do not have material exposure to the affected banks, the spread or potential spread of these or other issues to the broader financial sector could have a material adverse effect on our operating results, financial condition and prospects.

Central banks took extraordinary measures to increase liquidity in the financial markets as a response to the financial crisis and the covid-19 pandemic. In Europe, the ECB’s pandemic emergency purchase programme (PEPP) was finalized by the end of March 2022, although maturing principal payments are expected to be repurchased until at least the end of 2024. If these facilities, which are progressively being reduced, were to be rapidly removed, this could have an adverse effect on our ability to access liquidity and on our funding costs.

Additionally, our activities could be adversely impacted by liquidity tensions arising from generalized drawdowns of committed credit lines to our customers.

We cannot assure that in the event of a sudden or unexpected shortage of funds in the banking system, we will be able to maintain levels of funding without incurring high funding costs, a reduction in the term of funding instruments or the liquidation of certain assets. If this were to happen, we could be materially adversely affected.

Finally, the implementation of internationally accepted liquidity ratios might require changes in business practices that affect our profitability. The LCR is a liquidity standard that measures if banks have sufficient high-quality liquid assets to cover expected net cash outflows over a 30-day liquidity stress period. At 31 December 2022, our LCR ratio was 152%, above the 100% minimum requirement. The NSFR provides a sustainable maturity structure of assets and liabilities such that banks maintain a stable funding profile in relation to their activities. At the end of 2022, this ratio stands at 121% for the Group and over 100% for all our main subsidiaries.

Risks Relating to the Securities

Holders of any series of securities may experience a loss in their investment in the event Banco Santander becomes subject to a resolution process under Law 11/2015 (or in the event that loss absorption is required by the SRB to avoid a resolution process).

Chapter VI of Law 11/2015, of June 18, for the recovery and resolution of credit institutions and investment firms, as amended or superseded from time to time (“Law 11/2015”), regulates a set of measures targeted at ensuring that shareholders, subordinated creditors (including holders of securities) and certain senior creditors (including holders of securities) bear losses through a burden sharing mechanism within the framework of resolution processes. These measures could include the discharge of any indebtedness and a stay of payment in

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respect of any indebtedness imposed by the Single Resolution Board (the “SRB”), the Fondo de Reestructuración Ordenada Bancaria (the “FROB”) or any other entity with the authority to exercise the relevant tools and powers from time to time under Law 11/2015 (each, a “Relevant Resolution Authority”), even against the will or without the consent of those holding the relevant securities. Measures include repurchases of the debt securities at a certain price determined by the FROB, their exchange for other securities, the exercise of any Spanish Bail-in Power (as defined below) or Non-Viability Loss Absorption (as defined below).

The “Spanish Bail-in Power” means any write-down, conversion, transfer, modification, or suspension power existing from time to time under, and exercised in compliance with any laws, regulations, rules or requirements in effect in Spain, relating to the transposition of the Directive 2014/59/EU establishing a framework for the recovery and resolution of credit institutions and investment firms, as may be amended or superseded from time to time or come into effect in place thereof (the “BRRD”), including, but not limited to (i) Law 11/2015 (as defined herein), (ii) Royal Decree 1012/2015, of 6 November developing Law 11/2015, as amended or superseded from time to time (“RD 1012/2015”), (iii) the Regulation (EU) No. 806/2014 of the European Parliament and of the Council of 15 July 2014, establishing uniform rules and a uniform procedure for the resolution of credit institutions and certain investment firms in the framework of a Single Resolution Mechanism and a Single Resolution Fund and amending Regulation (EU) No. 1093/2010, as amended or superseded from time to time (“SRM Regulation”), and (iv) any other instruments, rules or standards made in connection with either (i), (ii) or (iii), pursuant to which any obligations of an institution can be reduced, cancelled, modified, or converted into shares, other securities, or other obligations of such institution or any other person (or suspended for a temporary period).

In accordance with Article 48 of Law 11/2015 (and subject to any exclusions that may be applied by the Relevant Resolution Authority under Article 43 of Law 11/2015), in the case of any application of the Spanish Bail-in Power, the sequence of any resulting write-down or conversion by the Relevant Resolution Authority shall be as follows: (i) instruments qualifying as CET1 Capital (“Common Equity Tier 1 Instruments”); (ii) the principal amount of Additional Tier 1 Instruments; (iii) the principal amount of Tier 2 Instruments; (iv) the principal amount of other subordinated claims that do not qualify as Additional Tier 1 Capital or Tier 2 Capital; and (v) the principal or outstanding amount of the other liabilities subject to bail-in as prescribed in Article 41 of Law 11/2015. Any application of the Spanish Bail-in Power under the BRRD shall be in accordance with the hierarchy of claims in normal insolvency proceedings (with “non-preferred” senior claims subject to the Spanish Bail-in Power after any subordinated claims against Banco Santander but before the other senior claims against Banco Santander).

In addition to the Spanish Bail-in Power, the BRRD, Article 38 of Law 11/2015 and the SRM Regulation provide for the Relevant Resolution Authority to have the further power to permanently write-down (including to zero) or convert into equity capital instruments (such as the Additional Tier 1 Instruments or the Tier 2 Instruments) and certain internal eligible liabilities at the point of non-viability of an institution or a group of which the institution forms part (the “Non-Viability Loss Absorption”). The point of non-viability of an institution is the point at which the Relevant Resolution Authority determines that the institution meets the conditions for resolution, or that it will no longer be viable unless the relevant capital instruments are written down or converted into equity, or that extraordinary public support is to be provided and without such support the Relevant Resolution Authority determines that the institution would no longer be viable. The point of non-viability of a group is the point at which the group infringes or there are objective elements to support a determination that the group, in the near future, will infringe its consolidated solvency requirements in a way that would justify action by the Relevant Resolution Authority in accordance with Article 38.3 of Law 11/2015. Non-Viability Loss Absorption may be imposed prior to or in combination with any exercise of the Spanish Bail-in Power or any other resolution tool or power (where the conditions for resolution referred to above are met).

Any application of the Spanish Bail-in Power and the Non-Viability Loss Absorption shall be in accordance with the hierarchy of claims in normal insolvency proceedings (unless otherwise provided by Applicable

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Banking Regulations). Accordingly, the impact of such application on holders will depend on the ranking of the relevant securities in accordance with such hierarchy, including any priority given to other creditors such as depositors.

Potential investors in the securities of any series should consider the risk that a holder may lose all or part of its investment if Banco Santander became the subject of a resolution process (or, in the case of investors in the subordinated debt securities or contingent convertible capital securities of any series, in the event that loss absorption were required by the SRB to avoid a resolution process of Banco Santander and a loss absorption measure was taken with respect to the securities of such series in accordance with Chapter VI of Law 11/2015).

There is no active trading market for the securities.

Securities issued pursuant to this prospectus (other than Banco Santander’s ordinary shares) will be new securities which may not be widely distributed and for which there is currently no active trading market and no active trading market may develop. If securities of any series are traded after their initial issuance, they may trade at a discount to their initial offering price, depending on a number of factors, including: prevailing interest rates, the number of holders of such series of securities, the market for similar securities, general economic conditions and the financial condition of Banco Santander and Banco Santander’s credit ratings published by credit rating agencies, the interest of securities dealers in making a market for such series of securities and the introduction or amendment of any financial transaction tax. Although Banco Santander may submit applications to list any series of securities on recognized stock exchanges, there is no assurance that such applications will be accepted, that any particular series of securities will be so admitted or that an active trading market will develop, or if developed, that it will continue. If an active trading market does not develop or is not maintained in respect of a particular series of securities, the market price and liquidity of the securities of such series, as applicable, may be adversely affected. In that case, holders of the securities of such series may not be able to sell the securities of such series at a particular time or may not be able to sell securities of such series at a favorable price.

The securities of any series are subject to the subordination provisions of the Spanish Insolvency Law.

Under Article 281 of the restated text of the Spanish Insolvency Law (Ley Concursal) approved by the approved by the Royal Decree-Legislative 1/2020, of 5 May (Real Decreto Legislativo 1/2020, de 5 de mayo, por el que se aprueba el texto refundido de la Ley Concursal) (as amended, the “Spanish Insolvency Law”) read in conjunction with Additional Provision 14.3 of Law 11/2015, Banco Santander will meet subordinated claims after payment in full of unsubordinated claims, but before distributions to shareholders, in the following order and pro-rata within each class: (i) late or incorrect claims; (ii) contractually subordinated liabilities in respect of principal (except for those under instruments of Banco Santander that qualify as Additional Tier 1 Capital or Tier 2 Capital, such as the contingent convertible capital securities and the subordinated securities, respectively); (iii) interest (including accrued and unpaid interest due on the securities, except for interest under contingent convertible or subordinated securities qualifying as Additional Tier 1 Capital or Tier 2 Capital); (iv) fines; (v) claims of creditors which are specially related to Banco Santander (if applicable) as provided for under the Spanish Insolvency Law; (vi) detrimental claims against Banco Santander where a Spanish court has determined that the relevant creditor has acted in bad faith (rescisión concursal); (vii) claims arising from contracts with reciprocal obligations as referred to in Articles 156 to 158 and 160 to 167 of the Spanish Insolvency Law, wherever the court rules, prior to the administrators’ report of insolvency (administración concursal) that the creditor repeatedly impedes the fulfilment of the contract against the interest of the insolvency; (viii) subordinated obligations (créditos subordinados) of Banco Santander under instruments qualifying as Tier 2 Capital (such as the subordinated securities) and (ix) subordinated obligations (créditos subordinados) of Banco Santander under instruments qualifying as Additional Tier 1 Capital (such as the contingent convertible capital securities).

In addition, Second paragraph of Article 48(7) of BRRD, as implemented in Spain through Additional Provision 14.3 of Law 11/2015, clarified that if an instrument is only partly recognised as an own funds

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instrument and, in the event of insolvency, the whole instrument shall be treated as a claim resulting from an own funds instrument and shall rank junior to any claim that does not result from an own funds instrument.

The Spanish Insolvency Law provides, among other things, that interest (other than interest accruing under secured liabilities up to an amount equal to the value of the security provided) shall cease to accrue as from the date of the declaration of insolvency and any amount of interest accrued up to such date (other than any interest accruing under secured liabilities up to an amount equal to the value of the security provided and interests accruing under contingent convertible capital securities or subordinated securities qualifying as Additional Tier 1 Capital or Tier 2 Capital), will be subject to the subordination provisions of Article 281.1.3° of the Spanish Insolvency Law.

The Spanish Insolvency Law, in certain instances, also has the effect of modifying or impairing creditors’ rights even if the creditor, either secured or unsecured, does not consent to the amendment. Secured and unsecured dissenting creditors may be written down not only once the insolvency has been declared by the judge as a result of the approval of a creditors’ agreement, but also as a result of an out-of-court restructuring agreement without insolvency proceedings having been previously opened (e.g., refinancing agreements which satisfy certain requirements and are validated by the judge), in both scenarios (i) to the extent that certain qualified majorities are achieved and unless (ii) some exceptions in relation to the kind of claim or creditor apply (which would not be the case for the securities).

The majorities legal regime envisaged for these purposes also hinges on (i) the type of the specific restructuring measure which is intended to be imposed (e.g., extensions, debt reductions, debt for equity swaps, etc.) as well as (ii) on the part of claims to be written-down (i.e. secured or unsecured, depending on the value of the collateral as calculated pursuant to the rules established in the Spanish Insolvency Law).

In no case shall subordinated creditors be entitled to vote upon a creditors’ agreement during the insolvency proceedings, and accordingly, shall be always subject to the measures contained therein, if passed.

Under the terms of the securities of any series, holders of such securities shall have agreed to be bound by and consent to the exercise of any resolution tool by the Relevant Resolution Authority.

Notwithstanding any other term of the securities of any series or any other agreements, arrangements, or understandings between Banco Santander and any holder of the securities of any series, by its acquisition of the securities of any series, each holder (which, for the purposes of this risk, includes each holder of a beneficial interest in the securities of any series) acknowledges, accepts, consents and agrees to be bound by the effect of the exercise of any resolution tools (including the bail-in tool, the sale of business tool, the bridge institution tool, and the asset separation tool) by the Relevant Resolution Authority in compliance with any laws, regulations, rules or requirements in effect in the Kingdom of Spain, relating to (i) the transposition of BRRD, including but not limited to Law 11/2015, and RD 1012/2015 (ii) the SRM Regulation and (iii) the instruments, rules and standards created thereunder.

The potential impact of any resolution tool may include the total loss of value of the securities of any series, and under certain circumstances, the inability of Banco Santander to perform its obligations under its securities.

See “—Law 11/2015 enables a range of actions to be taken in relation to credit institutions and investment firms considered to be at risk of failing. The taking of any action under Law 11/2015 could materially affect the value of any debt securities or contingent convertible capital securities” below for a further description of the range of actions which may be taken.

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Law 11/2015 enables a range of actions to be taken in relation to credit institutions and investment firms considered to be at risk of failing. The taking of any action under Law 11/2015 could materially affect the value of any debt securities or contingent convertible capital securities.

The BRRD (which has been implemented in Spain through Law 11/2015 and RD 1012/2015) is designed to provide authorities with a credible set of tools to intervene sufficiently early and quickly in unsound or failing credit institutions or investment firms (each an “institution”) so as to ensure the continuity of the institution’s critical financial and economic functions, while minimizing the impact of an institution’s failure on the economy and financial system.

As provided in the BRRD and SRM Regulation, Law 11/2015 contains four resolution tools and powers which may be used alone or in combination where the Relevant Resolution Authority considers that (a) an institution is failing or likely to fail, (b) there is no reasonable prospect that any alternative private sector measures would prevent the failure of such institution within a reasonable timeframe, and (c) a resolution action is in the public interest.

The four resolution tools are: (i) sale of business—which enables resolution authorities to direct the sale of the firm or the whole or part of its business on commercial terms; (ii) bridge institution—which enables resolution authorities to transfer all or part of the business of the firm to a “bridge institution” (an entity created for this purpose that is wholly or partially in public control); (iii) asset separation—which enables resolution authorities to transfer impaired or problem assets to one or more publicly owned asset management vehicles to allow them to be managed with a view to maximizing their value through eventual sale or orderly wind-down (this can be used together with another resolution tool only); and (iv) bail-in by which the Relevant Resolution Authority may exercise the Spanish Bail-in Power. This includes the ability of the Relevant Resolution Authority to write down (including to zero) and/or to convert into equity or other securities or obligations (which equity, securities or obligations could also be subject to any future application of the Spanish Bail-in Power) certain unsecured debt claims (including senior preferred debt securities and senior non preferred debt securities), subordinated obligations (including subordinated debt securities) and contingent convertible capital securities.

Law 11/2015 also provides for the resolution authority as a last resort, after having assessed and exploited the above resolution tools to the maximum extent possible while maintaining financial stability, to be able to provide extraordinary public financial support through additional financial stabilization tools. These consist of the public equity support and temporary public ownership tools. Any such extraordinary financial support must be provided in accordance with the EU state aid framework.

In accordance with Article 20 of Law 11/2015, an institution will be considered as failing or likely to fail in any of the following circumstances: (i) it is, or is likely in the near future to be, in significant breach of its solvency or any other requirements necessary for maintaining its authorization; (ii) its assets are, or are likely in the near future to be, less than its liabilities; (iii) it is, or is likely in the near future to be, unable to pay its debts as they fall due; or (iv) it requires extraordinary public financial support (except in limited circumstances). The determination that an institution is no longer viable may depend on a number of factors which may be outside of that institution’s control.

In addition to the Spanish Bail-in Power, the Relevant Resolution Authority may exercise Non-Viability Loss Absorption measures. Any shares issued to holders of debt securities or contingent convertible capital securities of such series upon any such conversion into equity may also be subject to any application of the Spanish Bail-in Power.

Any application of the Spanish Bail-in Power and Non-Viability Loss Absorption powers shall be in accordance with the hierarchy of claims in normal insolvency proceedings (unless otherwise provided by the Applicable Banking Regulations (as defined below)). Accordingly, the impact of such application on holders will depend on the ranking of the relevant instrument.

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In addition, in accordance with Article 64.1(i) of Law 11/2015, the Relevant Resolution Authority has the power to alter the amount of interest payable under debt instruments, contingent convertible capital securities and other eligible liabilities subject to resolution proceedings and the date on which the interest becomes payable under the debt instrument or contingent convertible capital securities (including the power to suspend payment for a temporary period).

The powers set out in the BRRD as implemented through Law 11/2015, RD 1012/2015 and the SRM Regulation will impact how credit institutions and investment firms are managed as well as, in certain circumstances, the rights of creditors. Holders of the debt securities or contingent convertible capital securities of any series may be subject, among others, to write-down and/or conversion into equity or other securities or obligations on any application of the Spanish Bail-in Power and, in the case of the subordinated debt securities and contingent convertible capital securities of any series, to Non-Viability Loss Absorption, which may result in such holders losing some or all of their investment.

The uncertainty may adversely affect the value of holders’ investments in the debt securities or contingent convertible capital securities and the price and trading behaviour of the debt securities or contingent convertible capital securities may be affected by the threat of a possible exercise of any power under Law 11/2015 (including any early intervention measure before any resolution) or any suggestion of such exercise. Moreover, the Relevant Resolution Authority may exercise any such power without providing any advance notice to the holders.

Because global securities will be held by or on behalf of DTC, investors will have to rely on their procedures for transfer, payment and communication with Banco Santander.

The securities of any series issued may be represented by one or more global securities. Such global securities will be registered with Cede & Co. as a nominee of the Depository Trust Company (“DTC”), and may be held through a DTC participant, including Euroclear and Clearstream. Except in the circumstances described in the relevant global security, investors will not be entitled to receive definitive securities. DTC will maintain records of the beneficial interests in the global securities. While the securities are represented by one or more global securities, investors will be able to trade their beneficial interests only through DTC (or any other clearing system that is a direct or indirect participant in DTC).

While the securities of any series are represented by one or more global securities, Banco Santander will discharge their payment obligations under the securities of such series by making payments to the common depositary or Principal Paying Agent for DTC for distribution to their account holders. A holder of a beneficial interest in a global security must rely on the procedures of DTC, or if such interest is held through a DTC participant, the procedures of such DTC participant, to receive payments under the relevant series of securities. Banco Santander has no responsibility or liability for the records relating to, or payments made in respect of, beneficial interests in the global securities.

Holders of beneficial interests in the global securities will not have a direct right to vote in respect of the relevant series of securities. Instead, such holders will be permitted to act only to the extent that they are enabled by DTC to appoint appropriate proxies. Similarly, holders of beneficial interests in the global securities will not have a direct right under the global securities to take enforcement action against Banco Santander in the event of a default under the relevant series of securities but will have to rely upon their rights under the relevant indenture.

If Banco Santander does not receive timely certain information related to securities of any series from the Principal Paying Agent (in order to provide such information to the Spanish tax authorities), payments on the securities will become subject to Spanish withholding tax and no additional amounts will be paid with respect thereto.

Article 44 of Royal Decree 1065/2007, as amended (“Royal Decree 1065/2007”) sets out the reporting obligations applicable to preferred securities (participaciones preferentes), such as the contingent convertible

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capital securities of any series, and debt instruments (such as the debt securities), in each case, issued under Law 10/2014 on the regulation, supervision and solvency of credit institutions (“Law 10/2014”). The procedures apply to income derived from preferred securities and debt instruments to which Law 10/2014 refers, including debt instruments issued at a discount for a period equal to or less than twelve months.

According to Article 44.5 of Royal Decree 1065/2007, income derived from preferred securities or debt instruments issued under Law 10/2014 and which have been originally registered with entities that manage clearing systems located outside Spain (provided that these entities are recognized by Spanish law or by the law of another Organization for Economic Cooperation and Development (“OECD”) country such as DTC, Euroclear and Clearstream, Luxembourg), will be paid free of Spanish withholding tax provided that the Principal Paying Agent appointed by Banco Santander submits, in a timely manner, a statement to Banco Santander, with the following information:

(i) identification of the securities;

(ii) income payment date (or refund if the securities are issued at discount or are segregated);

(iii) total amount of income (or total amount to be refunded if the securities are issued at discount or are segregated); and

(iv) total amount of the income corresponding to each clearing system located outside Spain.

For these purposes, “income” means interest and the difference, if any, between the aggregate amount payable on the redemption of the securities of any series and the issue price of the securities of such series.

In accordance with Article 44 of Royal Decree 1065/2007, the Principal Paying Agent should provide Banco Santander with the statement reflecting the relevant position at the close of business on the business day immediately prior to each interest payment date. In the event that on such date, an entity obliged to provide the declaration fails to do so, Banco Santander or the Principal Paying Agent on its behalf will make a withholding at the then applicable general rate (currently set at 19%) on the total amount of the return on the relevant debt securities or contingent convertible capital securities otherwise payable to their holders.

Notwithstanding the foregoing, in the event that withholding tax were required by law due to the failure of the Principal Paying Agent to submit in a timely manner a duly executed and completed certificate pursuant to Law 10/2014 and Royal Decree 1065/2007 and any implementing legislation or regulation, Banco Santander will not pay any additional amounts with respect to any such withholding, as provided in “Description of Debt Securities—Additional Amounts” and “Description of Contingent Convertible Capital Securities—Additional Amounts” below.

In the event that the currently applicable procedures are modified, amended or supplemented by, among other things, any Spanish law, regulation, interpretation or ruling of the Spanish tax authorities, Banco Santander will notify the holders of the relevant series of securities, as applicable, of such information procedures and their implications, as Banco Santander may be required to apply withholding tax on interest payments or Distributions, as applicable, in respect of the relevant series of securities if the holders of such series of securities do not comply with such information procedures.

Potential FATCA Withholding

Under certain provisions of the United States Internal Revenue Code of 1986, as amended, commonly referred to as “FATCA,” and Treasury regulations promulgated hereunder, certain payments made in respect of the debt securities, contingent convertible capital securities, ADSs or Conversion Shares may be subject to withholding at a rate of 30%, to the extent that such payments are considered to be “foreign passthru payments.” Banco Santander (or its paying agent or other financial intermediaries) may be required to withhold under FATCA on payments made to (i) non-U.S. financial institutions (including intermediaries) that have not entered

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into agreements with the Internal Revenue Service pursuant to FATCA or otherwise established an exemption from FATCA, and (ii) other holders that fail to provide sufficient identifying information to the relevant payor. The United States has entered into intergovernmental agreements for the implementation of FATCA with many jurisdictions (including Spain), which may modify these requirements. Under current guidance it is not clear whether and to what extent payments on the debt securities, contingent convertible capital securities, ADSs or Conversion Shares will be considered foreign passthru payments subject to withholding under FATCA, or whether and to what extent withholding on foreign passthru payments may be required under intergovernmental agreements and their implementing rules. Under proposed Treasury regulations, (the preamble to which specifies that taxpayers may rely on them pending finalization) FATCA withholding on foreign passthru payments will not be required prior to the date that is two years after the date on which final Treasury regulations defining the term foreign passthru payments are published in the U.S. Federal Register. In addition, FATCA withholding on foreign passthru payments will not be required with respect to securities treated as debt for U.S. federal income tax purposes that are issued on or before the date that is six months after the date on which final Treasury regulations defining the term foreign passthru payments are published in the U.S. Federal Register (provided that such debt securities are not materially modified thereafter, including, in certain circumstances, by reason of a substitution or variation by Banco Santander). Investors should consult their tax advisors as to whether and how these rules may apply to payments they receive on the debt securities, contingent convertible capital securities, ADSs or Conversion Shares.

The scope of the proposed European financial transaction tax is uncertain.

The European Commission published in February 2013 a proposal (the “Commission’s Proposal”) for a Directive for a common financial transaction tax (the “EU FTT”) in Belgium, Germany, Estonia, Greece, Spain, France, Italy, Austria, Portugal, Slovenia and Slovakia (excluding Estonia, the participating Member States). Estonia has since stated that it will not participate.

The Commission’s Proposal has very broad scope and could, if introduced, apply to certain dealings in financial instruments (including secondary market transactions) in certain circumstances. The issuance and subscription of financial instruments should, however, be exempt.

Under the Commission’s Proposal, the EU FTT could apply in certain circumstances to persons both within and outside of participating Member States. Generally, it would apply to certain dealings in financial instruments where at least one party is a financial institution, and at least one party is established in a participating Member State. A financial institution may be, or be deemed to be, “established” in a participating Member State in a broad range of circumstances, including (i) by transacting with a person established in a participating Member State or (ii) where the financial instrument which is subject to the dealings is issued in a participating Member State.

Under the Commission’s Proposal, the EU FTT involves a minimum 0.1% tax rate for transactions in all types of financial instruments, except for derivatives that would be subject to a minimum 0.01% tax rate.

On December 3, 2018, the finance ministers of France and Germany outlined a joint proposal for a limited FTT based on a system already in place in France. Under the new proposal, the tax obligation would apply only to transactions involving shares issued by participating Member State’s companies with a market capitalization of over €1 billion.

However, the Commission’s Proposal remains subject to negotiation between the participating Member States and the scope of any such tax is uncertain. It may therefore be changed prior to any implementation, the timing of which remains unclear. Additional EU Member States may decide to participate and participating Members States may withdraw.

Prospective investors are advised to seek their own professional advice in relation to the EU FTT.

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Notwithstanding the above, please bear in mind that Spain has implemented a Spanish tax on financial transactions which came into force on January 16, 2021. For more details see section “Taxation—Spanish Taxation—E. Spanish FTT.”

The implementation of the Global Minimum Tax may adversely affect Banco Santander’s future effective tax rates

On December 14, 2022, the Council of the EU approved Directive 2022/2523 on ensuring a global minimum level of taxation (“Global Minimum Tax”) for multinational enterprise groups and large-scale domestic groups in the EU. This directive introduces minimum effective taxation of 15% for multinational enterprise groups and large-scale domestic groups with annual revenues of at least €750 million in the consolidated financial statements in at least two of the four prior fiscal years.

Taxpayers included in the scope of the Global Minimum Tax should calculate their effective tax rate for each jurisdiction where they operate, and pay a “top-up tax” (as defined and detailed in the abovementioned directive) for the difference between their effective tax rate per jurisdiction and the 15% minimum rate. It is reasonable to expect that Banco Santander would be included in the scope of the Global Minimum Tax.

In addition, Directive 2022/2523 follows closely the OECD Inclusive Framework on Base Erosion and Profit Shifting and should be transposed by the Member States throughout 2023, entering into force generally on 1 January 2024. The OECD is working on the implementation guides and has recently approved a report on safe harbours in order to simplify the implementation of these rules.

The implementation of the Global Minimum Tax may adversely impact, among others, Banco Santander’s (i) future effective tax rates; (ii) the jurisdictions in which our profits are determined to be earned and taxed; and (iii) the application of available tax credits.

Prospective investors are advised to seek their own professional advice in relation to the Global Minimum Tax.

The market value of the securities is likely to be limited by early redemption features

Early redemption features are likely to limit the market value of the securities. During any period when Banco Santander may redeem the securities, the market value of those instruments generally will not rise substantially above the price at which they can be redeemed. Banco Santander may be expected to redeem the securities when its cost of borrowing is lower than the interest rate on the securities. At those times, an investor generally would not be able to reinvest the redemption proceeds at an effective interest rate as high as the interest rate on the securities being redeemed and may only be able to do so at a significantly lower rate. Potential investors should consider reinvestment risk in light of other investments available at that time.

Risks Relating to the Debt Securities

Under the terms of the debt securities of any series, holders of such securities shall have agreed to be bound by and consent to the exercise of any Spanish Bail-in Power and Non-Viability Loss Absorption by the Relevant Resolution Authority.

Pursuant to Article 46 of Law 11/2015, which implements Article 55 of the BRRD, subject to limited exceptions, unsecured liabilities of an institution governed by the laws of a third country (which include the debt securities of any series) must contain a contractual acknowledgment whereby the holders recognize that such liability may be subject to the Spanish Bail-in Power and agree to be bound by the exercise of those powers by the Relevant Resolution Authority. In addition, pursuant to article 63 of CRR, subordinated debt securities must contain a contractual acknowledgment whereby the holders recognize that such liability may be subject to the Non-Viability Loss Absorption and agree to be bound by the exercise of those powers by the Relevant Resolution Authority.

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Notwithstanding any other term of the debt securities of any series or any other agreements, arrangements, or understandings between Banco Santander and any holder of the debt securities of any series, by its acquisition of the debt securities of any series, each holder (which, for the purposes of this clause, includes each holder of a beneficial interest in the debt securities of any series) acknowledges, accepts, consents to and agrees to be bound by the exercise of any Spanish Bail-in Power and, in the case of subordinated debt securities, any Non-Viability Loss Absorption by the Relevant Resolution Authority that may result in the write-down or cancellation of all or a portion of the Amounts Due on the debt securities and/or the conversion of all or a portion of the Amounts Due on the debt securities into shares or other securities or other obligations of Banco Santander or another person, including by means of a variation to the terms of the debt securities to give effect to the exercise by the Relevant Resolution Authority of such powers. Each holder of the debt securities further acknowledges and agrees that the rights of the holders of the debt securities are subject to—and will be varied, if necessary, so as to give effect to—the exercise of any Spanish Bail-in Power and, in the case of subordinated debt securities, any Non-Viability Loss Absorption by the Relevant Resolution Authority.

For these purposes, the “Amounts Due” are the principal amount of, premium, if any, together with any accrued but unpaid interest, and Additional Amounts, if any, due on the debt securities of any series. References to such amounts will include amounts that have become due and payable, but which have not been paid, prior to the exercise of the Spanish Bail-in Power by the Relevant Resolution Authority.

Any Spanish Bail-in Power or Non-Viability Loss Absorption may be exercised in such a manner as to result in holders of debt securities of the relevant series losing the value of all or a part of their investment in the securities of such series or receiving a different security from the securities of such series, which may be worth significantly less than the securities of such series and which have significantly fewer protections than those typically afforded to those kinds of securities. Moreover, the Relevant Resolution Authority may exercise its authority to implement the Spanish Bail-in Power or Non-Viability Loss Absorption without providing any advance notice to the holders of the debt securities of such series. For more information, see “Description of Debt Securities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power.”

Holders of the debt securities of any series are likely to have limited rights to challenge the exercise of the Spanish Bail-in Power or Non-Viability Loss Absorption by the Relevant Resolution Authority.

Law 11/2015 contains certain safeguards for creditors in respect of the application of the capital instruments write-down and conversion power and the bail-in tool.

With respect to the capital instruments write-down and conversion power, the Relevant Resolution Authority will exercise such power in accordance with the priority of claims under normal insolvency proceedings such that Common Equity Tier 1 Instruments will be written down before Additional Tier 1 Instruments and Tier 2 Instruments, successively, are written down or converted into Common Equity Tier 1 Instruments.

In accordance with Article 48 of Law 11/2015 (and subject to any exclusions that may be applied by the Relevant Resolution Authority under Article 43 of Law 11/2015), in the case of any application of the Spanish Bail-in Power, the sequence of any resulting write-down or conversion by the Relevant Resolution Authority shall be as follows: (i) Common Equity Tier 1 Instruments; (ii) the principal amount of Additional Tier 1 Instruments, (iii) the principal amount of Tier 2 Instruments; (iv) the principal amount of other subordinated claims that do not qualify as Additional Tier 1 Instruments or Tier 2 Instruments; and (v) the principal or outstanding amount of the eligible liabilities (pasivos admisibles) prescribed in Article 41 of Law 11/2015. Any application of the Spanish Bail-in Power under the BRRD shall be in accordance with the hierarchy of claims in normal insolvency proceedings (unless otherwise provided by applicable banking regulations).

Notwithstanding the above, there may be limited protections, if any, that will be available to holders of securities subject to the Spanish Bail-in Power (including the debt securities of any series) or to Non-Viability

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Loss Absorption and to the broader resolution powers of the Relevant Resolution Authority. Accordingly, holders of debt securities of any series may have limited or circumscribed rights to challenge any decision of the Relevant Resolution Authority to exercise its Spanish Bail-in Power or Non-Viability Loss Absorption.

The circumstances under which the Relevant Resolution Authority would exercise its Spanish Bail-in Power or Non-Viability Loss Absorption are currently uncertain.

There remains uncertainty as to how or when the Spanish Bail-in Power and/or, in case of subordinated debt, Non-Viability Loss Absorption may be exercised and how it would affect the Group and the holders of debt securities of any series. The exercise of the Spanish Bail-in Power and/or Non-Viability Loss Absorption by the Relevant Spanish Resolution Authority is likely to be inherently unpredictable and may depend on a number of factors which may be outside of Banco Santander’s control. Although there are proposed pre-conditions for the exercise of the Spanish Bail-in Power or Non-Viability Loss Absorption, there remains uncertainty regarding the specific factors which the Relevant Resolution Authority would consider in deciding whether to exercise the Spanish Bail-in Power or Non-Viability Loss Absorption with respect to the financial institution and/or securities issued or guaranteed by that institution. In addition, as the Relevant Resolution Authority will retain an element of discretion, holders of debt securities of any series may not be able to refer to publicly available criteria in order to anticipate a potential exercise of any such Spanish Bail-in Power and/or, in case of subordinated debt, Non-Viability Loss Absorption. Because of this inherent uncertainty, it will be difficult to predict when, if at all, the exercise of any such powers, may occur which would result in a principal amount write off or conversion to equity.

This uncertainty may adversely affect the value of holders’ investments in the debt securities of any series and the price and trading behavior of the debt securities may be affected by the threat of a possible exercise of any power under Law 11/2015 (including any early intervention measure before any resolution) or any suggestion of such exercise, even if the likelihood of such exercise is remote. Moreover, the Relevant Resolution Authority may exercise any such power without providing any advance notice to the holders of debt securities.

Changes in law or the official interpretation by regulatory authorities such as the Bank of Spain or the European Central Bank may adversely affect holders’ rights under the debt securities of any series or may adversely affect the Group’s business, financial performance and capital plans.

Changes in law or the official interpretation by regulatory authorities such as the Bank of Spain or the European Central Bank after the date hereof may affect holders’ rights under the debt securities of any series and effective remedies of holders, as well as the market value of the debt securities of such series. Such changes in law may include changes in statutory, tax and regulatory regimes during the life of the debt securities of any series, or changes that could have a significant impact on the future legal entity structure, business mix (including a potential exit of certain business activities) and management of the Group, and use of capital and requirements for loss-absorbing capacity within the Group, which may have an adverse effect on an investment in the debt securities of such series.

Any change in law or regulation (or the official interpretation by regulatory authorities) that would cause the senior non preferred debt securities or the senior preferred of any series to fail to fully qualify as TLAC/MREL Eligible Instruments or subordinated debt securities of any series to be fully excluded (or likely to be fully excluded) from Tier 2 Capital would trigger a TLAC/MREL Disqualification Event or Capital Disqualification Event, respectively, entitles Banco Santander to redeem the senior non preferred debt securities, senior preferred debt securities (to the extent specified in the applicable prospectus supplement) or subordinated debt securities of such series, as applicable, in whole (but not in part) as more particularly described under “Description of Debt Securities—Redemption and Repurchase—Early Redemption of Senior Debt Securities for a TLAC/MREL Disqualification Event” and “Description of Debt Securities—Redemption and Repurchase—Early Redemption of Subordinated Debt Securities for a Capital Disqualification Event”. In addition, any change in law or regulation that results in Banco Santander having to pay additional amounts to holders of debt securities of any

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series, or results in certain other tax consequences including (but not limited to) Banco Santander not being entitled to claim a deduction for Spanish tax purposes in respect of interest payments (or the value of such deduction to us being materially reduced), could trigger a tax event, which may entitle Banco Santander to redeem the debt securities of such series, in whole (but not in part) as more particularly described under “Description of Debt Securities—Redemption and Repurchase—Early Redemption for Taxation Reasons”.

It is not possible to predict whether or not a change in the laws or regulations of Spain, Applicable Banking Regulations or the application or official interpretation thereof, will occur and so lead to the circumstances in which Banco Santander is able to elect to redeem the debt securities of any series, and if so whether or not Banco Santander will elect to exercise such option to redeem the debt securities of such series. There can be no assurances that, in the event of any early redemption, holders of debt securities of any series will be able to reinvest the proceeds at a rate that is equal to the return on the debt securities of such series.

Any legislative and regulatory uncertainty could also affect holders’ ability to accurately value the debt securities of any series and therefore affect the trading price of the debt securities of such series given the extent and impact on the debt securities of such series that one or more regulatory or legislative changes, including those described under “—The circumstances under which the Relevant Resolution Authority would exercise its Spanish Bail-in Power or Non-Viability Loss Absorption are currently uncertain” and “—Holders of the debt securities of any series are likely to have limited rights to challenge the exercise of the Spanish Bail-in Power or Non-Viability Loss Absorption by the Relevant Resolution Authority”, could have on the debt securities of such series.

Changes in law may adversely affect Banco Santander’s future effective tax rates.

There are a number of factors that may adversely impact Banco Santander’s future effective tax rates, such as: (i) the jurisdictions in which our profits are determined to be earned and taxed; (ii) changes in the valuation of our deferred tax assets and liabilities; (iii) adjustments to provisional taxes upon finalization of various tax returns; (iv) adjustments to the interpretation of transfer pricing standards; (v) changes in available tax credits; (vi) changes in IFRS; (vii) changes in tax laws or the interpretation of tax laws (e.g., in connection with fundamental United States international tax reform or in connection with the introduction of the global minimum tax).

Credit ratings may not reflect all risks of an investment in the debt securities, and a downgrade in credit ratings, including as a result of changes in rating agencies’ views of the level of implicit sovereign support for European banks, could adversely affect the trading prices of the debt securities.

Banco Santander’s credit ratings may not reflect the potential impact of all risks relating to the market values of the debt securities of any series. However, real or anticipated changes in Banco Santander’s credit ratings will generally affect the market values of the debt securities of such series. Credit rating agencies continually revise their ratings for companies that they follow, including Banco Santander, and as such, the credit rating of Banco Santander may be revised, suspended or withdrawn at any time by the assigning rating organization at their sole discretion. In addition, one or more independent credit rating agencies may assign credit ratings to the debt securities of any series.

Any ratings downgrade could adversely affect the trading prices of the debt securities of any series or the trading markets for the debt securities of any series to the extent trading markets for the debt securities of such series develop, and any ratings improvement will not necessarily increase the value of the debt securities of such series and will not reduce market risk and other investment risks related to the debt securities of such series.

Credit ratings may not reflect the potential impact of all risks related to structure and market of the debt securities of any series, and do not address the price, if any, at which the debt securities of any series may be resold prior to maturity (which may be substantially less than the original offering price of the debt securities of

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such series), and other factors that may affect the value of the debt securities of such series. A credit rating is not a recommendation to buy, sell or hold the debt securities of any series and may be revised or withdrawn by the rating agency at any time. Potential investors should not rely on any rating of the debt securities and should make their investment decision on the basis of considerations such as those outlined above.

In general, European regulated investors are restricted under Regulation (EC) No. 1060/2009 (as amended) (the “CRA Regulation”) from using credit ratings for regulatory purposes in the EEA, unless such ratings are issued by a credit rating agency established in the EU and registered under such regulation (and such registration has not been withdrawn or suspended), subject to transitional provisions that apply in certain circumstances whilst the registration application is pending. Such general restriction will also apply in the case of credit ratings issued by third-country non-EEA credit rating agencies, unless the relevant credit ratings are endorsed by an EEA-registered credit rating agency or the relevant third-country rating agency is certified in accordance with the CRA Regulation (and such endorsement action or certification, as the case may be, has not been withdrawn or suspended). Investors regulated in the United Kingdom are subject to similar restrictions under the CRA Regulation as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 (the “UK CRA Regulation”). Certain information with respect to the credit rating agencies and ratings will be disclosed in the relevant prospectus supplement.

The debt securities may not be a suitable investment for investors.

Prospective investors should determine whether an investment in any series of debt securities is appropriate in light of their own particular circumstances after carefully considering, in conjunction with their legal, business and tax advisors, the consequences of an investment in the debt securities of such series and the other information set out in this prospectus and the relevant prospectus supplement, to arrive at their own evaluation of the investment. Banco Santander does not make any recommendation as to whether any series of debt securities are a suitable investment for any person.

The debt securities of any series may be redeemed by Banco Santander prior to maturity.

The debt securities of any series may be redeemable at Banco Santander’s option in certain circumstances as described in this prospectus and the relevant prospectus supplement. Banco Santander may choose to redeem the debt securities of such series at times when prevailing interest rates may be relatively low. In such circumstances, an investor may not be able to reinvest the redemption proceeds in a comparable security at an effective interest rate as high as that of the relevant debt securities. The effective interest rate may even be significantly lower.

In addition, the ability to redeem the debt securities of any series is likely to limit the market value of the debt securities of such series. During any period when Banco Santander may elect to redeem the debt securities of any series, the market value of the debt securities of such series generally will not rise substantially above the price at which they can be redeemed. This also may be true prior to any redemption period. See “Description of Debt Securities—Redemption and Repurchase” for more information on the circumstances under which Banco Santander may redeem the debt securities of any series.

The debt securities of any series are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation, the Deposit Insurance Fund, or any other government agency.

The debt securities of any series are Banco Santander’s obligations but are not bank deposits. The debt securities carry risks which are very different from the risk profile of a bank deposit placed with Banco Santander or any of its affiliates (e.g., different yield or liquidity). In the event of Banco Santander’s insolvency, the debt securities of any series will rank equally with Banco Santander’s other unsecured obligations and will not have the benefit of any insurance or guarantee provided to deposits by the Federal Deposit Insurance Corporation, the Deposit Insurance Fund, or any other government agency.

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There is no restriction under the relevant indentures on the amount or type of further securities or indebtedness which Banco Santander may incur.

There is no restriction under the relevant indentures on the amount or type of further securities or indebtedness which Banco Santander may issue or incur which ranks senior to, or pari passu with, the debt securities of any series. The incurrence of any such further indebtedness may reduce the amount recoverable by holders of debt securities of any series on a liquidation, dissolution or winding-up of Banco Santander in respect of the debt securities of such series and may limit the ability of Banco Santander to meet its obligations in respect of the debt securities of such series, and result in a holder of the debt securities of such series losing all or some of its investment in the debt securities of such series.

The terms of the debt securities contain a waiver of set-off rights.

No holder of the senior preferred debt securities where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement, senior non preferred debt securities of any series or the subordinated debt securities of any series may at any time exercise or claim any right, of or claim for, deduction, set-off, netting, compensation, retention or counterclaim arising directly or indirectly under or in connection with the relevant securities against any right, claim or liability of Banco Santander or that Banco Santander may have or acquire against such holder, directly or indirectly and howsoever arising (and including all such rights, claims and liabilities arising under or in relation to any and all agreements or other instruments of any kind, whether or not relating to such debt securities).

The terms and conditions of the senior preferred debt securities where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement, senior non preferred debt securities of any series and the subordinated debt securities of any series provide that holders shall be deemed to have waived all rights, of or claims for, deduction, set-off, netting, compensation, retention or counterclaim arising directly or indirectly under or in connection with the relevant securities to the fullest extent permitted by applicable law in relation to all such actual and potential rights, claims and liabilities. As a result, holders will not at any time be entitled to set-off Banco Santander’s obligations under the relevant securities against obligations owed by them to Banco Santander.

Risks Related to the Senior Preferred Debt Securities

The senior preferred debt securities of any series are unsecured and are effectively subordinated to Banco Santander’s secured indebtedness.

The senior preferred debt securities of any series are unsecured, will be effectively subordinated to all secured indebtedness Banco Santander may incur, to the extent of the assets securing such indebtedness. The relevant indenture relating to Banco Santander’s senior preferred debt securities does not restrict Banco Santander’s ability to incur secured indebtedness in the future. In the event of Banco Santander’s insolvency, bankruptcy, liquidation, reorganization, dissolution or winding up, to the extent Banco Santander has granted security over Banco Santander’s assets, the assets securing such indebtedness will be used to satisfy the obligations under such indebtedness before Banco Santander can make payments on the senior preferred debt securities of any series. There may only be limited assets available to make payments on the senior preferred debt securities of any series in the event of an acceleration of the senior preferred debt securities of such series and Banco Santander may not have sufficient assets to pay amounts due on any or all of Banco Santander’s senior preferred debt securities of such series then outstanding.

In the event that the senior preferred debt securities of any series are subject to redemption, such senior preferred debt securities may be subject to substitution and/or variation without a holder’s consent

Subject as provided herein, in particular under “Description of Debt Securities—Substitution and Variation”, if the applicable prospectus supplement for a series of senior preferred debt securities specifies that

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such senior preferred debt securities are subject to redemption and a TLAC/MREL Disqualification Event or a tax event that would entitle Banco Santander to redeem the senior preferred debt securities as set forth under “Description of Debt Securities—Redemption and Repurchase—Early Redemption for Taxation Reasons” occurs, Banco Santander may, at its option, and without the consent or approval of the holders of the relevant debt securities, elect either (i) to substitute all (but not only some) of the relevant debt securities or (ii) to modify the terms of all (but not only some) of the relevant debt securities, in each case so that they are substituted for, or varied to, become, or remain, Qualifying Notes. While Qualifying Notes generally must contain terms that are materially no less favorable to holders of the relevant debt securities as the original terms of the relevant debt securities, there can be no assurance that the terms of any Qualifying Notes will be viewed by the market as equally favorable, or that the Qualifying Notes will trade at prices that are equal to the prices at which the relevant debt securities would have traded on the basis of their original terms.

Further, prior to the making of any such substitution or variation, Banco Santander, shall not be obliged to have regard to the tax position of individual holders of the relevant debt securities or to the tax consequences of any such substitution or variation for any such individual holder. No holder of the relevant debt securities shall be entitled to claim, whether from the Trustee, Banco Santander, or any other person, any indemnification or payment in respect of any tax consequence of any such substitution or variation upon an individual holder of the relevant debt securities.

Certain senior preferred debt securities may be redeemed prior to maturity upon the occurrence of a TLAC/MREL Disqualification Event

When so specified in the prospectus supplement, Banco Santander may, at its option, redeem all, but not some only, of the senior preferred debt securities, at any time at their early redemption amount, together with accrued but unpaid interest up to (but excluding) the date of redemption, upon or following the occurrence of a TLAC/MREL Disqualification Event.

The early redemption of the senior preferred debt securities may be subject to the prior consent of the Relevant Resolution Authority if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time.

Risks Related to the Senior Non Preferred Debt Securities

Banco Santander’s obligations under the senior non preferred debt securities of any series are junior to certain obligations.

Banco Santander’s obligations under the senior non preferred debt securities of any series will be direct, unconditional, unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander in accordance with Additional Provision 14.2 of Law 11/2015. Upon the insolvency of Banco Santander, the payment obligations of Banco Santander in respect of principal under the senior non preferred debt securities rank, subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), (a) pari passu among themselves and with any Senior Non Preferred Liabilities (as defined below), (b) junior to the Senior Higher Priority Liabilities (as defined below) (and, accordingly, upon the insolvency of Banco Santander the payment obligations of Banco Santander in respect of principal under the senior non preferred debt securities of any series will be met after payment in full of the Senior Higher Priority Liabilities) and (c) senior to any present and future subordinated obligations (créditos subordinados) of Banco Santander in accordance with Article 281 of the Spanish Insolvency Law.

Banco Santander’s Senior Higher Priority Liabilities would include, among other liabilities, its deposit obligations (other than the deposit obligations qualifying as preferred liabilities (créditos con privilegio general) under Additional Provision 14.1 of Law 11/2015, which will rank senior to the senior non preferred debt securities of any series), its obligations in respect of derivatives and other financial contracts and its

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unsubordinated and unsecured debt securities other than the Senior Non Preferred Liabilities. If Banco Santander were wound up or liquidated, Banco Santander expects that a liquidator would apply the assets which are available to satisfy all claims in respect of its unsubordinated and unsecured liabilities, first to satisfy claims of all other creditors ranking ahead of holders, including holders of Senior Higher Priority Liabilities, and then to satisfy claims in respect of the senior non preferred debt securities of any series (and other Senior Non Preferred Liabilities). If Banco Santander does not have sufficient assets to settle the claims of higher ranking creditors in full, the claims of the holders under the senior non preferred debt securities of any series will not be satisfied. Holders will share equally in any distribution of assets available to satisfy all claims in respect of its unsubordinated and unsecured liabilities with the creditors under any other Senior Non Preferred Liabilities if Banco Santander does not have sufficient funds to make full payment to all of them.

In addition, if Banco Santander enters into resolution, its eligible liabilities (including the senior non preferred debt securities) may be subject to bail-in, meaning potential write-down or conversion into equity securities or other instruments. The sequence of any resulting write-down or conversion of eligible instruments under Article 48 of the BRRD and Article 48 of Law 11/2015 provides for claims to be written down or converted into equity in accordance with the hierarchy of claims provided in the applicable insolvency legislation. Because the senior non preferred debt securities of any series are senior non preferred obligations (créditos ordinarios no preferentes), Banco Santander expects them to be written down or converted in full after any subordinated obligations of Banco Santander under Article 281 of the Spanish Insolvency Law and before any of Banco Santander’s Senior Higher Priority Liabilities are written down or converted. Banco Santander expects that upon insolvency, the payment obligations in respect of principal under the senior non preferred debt securities of any series would rank pari passu with any obligations in respect of principal of any senior non preferred debt securities or any other securities with the same ranking issued by Banco Santander.

As a consequence, holders of the senior non preferred debt securities of any series bear significantly more risk than holders of Banco Santander’s Senior Higher Priority Liabilities and could lose all or a significant part of their investment if Banco Santander were to become (i) subject to resolution under the BRRD (as implemented through Law 11/2015 and RD 1012/2015) and the senior non preferred debt securities of any series become subject to the application of the Spanish Bail-in Power or (ii) insolvent.

The senior non preferred debt securities provide for limited events of default.

Holders have no ability to accelerate the maturity of their senior non preferred debt securities. The terms and conditions of the senior non preferred debt securities do not provide for any events of default, except in the case that an order is made by any competent court commencing insolvency proceedings against Banco Santander or for its winding up or liquidation. Accordingly, in the event that any payment on the senior non preferred debt securities of any series is not made when due, each holder of such series will have a claim only for amounts then due and payable on their senior non preferred debt securities.

The senior non preferred debt securities of any series may be subject to substitution and/or variation without a holder’s consent

Subject as provided herein, in particular under “Description of Debt Securities—Substitution and Variation”, if a TLAC/MREL Disqualification Event or a tax event that would entitle Banco Santander to redeem the debt securities as set forth under “Description of Debt Securities—Redemption and Repurchase—Early Redemption for Taxation Reasons” occurs, Banco Santander may, at its option, and without the consent or approval of the holders of the senior non preferred debt securities of such series, elect either (i) to substitute all (but not some only) of the senior non preferred debt securities of such series or (ii) to modify the terms of all (but not some only) of the senior non preferred debt securities of such series, in each case so that they are substituted for, or varied to, become, or remain, Qualifying Notes. While Qualifying Notes generally must contain terms that are materially no less favorable to holders of the senior non preferred debt securities of such series as the original terms of the senior non preferred debt securities of such series, there can be no assurance that the terms of any

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Qualifying Notes will be viewed by the market as equally favorable, or that the Qualifying Notes will trade at prices that are equal to the prices at which the senior non preferred debt securities of such series would have traded on the basis of their original terms.

Further, prior to the making of any such substitution or variation, Banco Santander, shall not be obliged to have regard to the tax position of individual holders of the senior non preferred debt securities of such series or to the tax consequences of any such substitution or variation for any such individual holder. No holder of the senior non preferred debt securities of such series shall be entitled to claim, whether from the Trustee, Banco Santander, or any other person, any indemnification or payment in respect of any tax consequence of any such substitution or variation upon an individual holder of the senior non preferred debt securities of such series.

The senior non preferred debt securities may be redeemed prior to maturity upon the occurrence of a TLAC/MREL Disqualification Event

Banco Santander may, at its option, redeem all, but not some only, of the senior non preferred debt securities, at any time at their early redemption amount, together with accrued but unpaid interest up to (but excluding) the date of redemption, upon or following the occurrence of a TLAC/MREL Disqualification Event.

The early redemption of the senior non preferred debt securities may be subject to the prior consent of the Relevant Resolution Authority if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time.

Article 78a of CRR provides that the redemption of MREL eligible liabilities (such as the senior non-preferred debt securities) prior to the date of their contractual maturity is subject to the prior permission of the resolution authority. Such consent will be given only if one of the following conditions is met:

It is not possible to predict whether any further change in the laws or regulations of Spain, Applicable Banking Regulations or in the application or official interpretation thereof will occur and so lead to the circumstances in which Banco Santander is able to elect to redeem the senior non preferred debt securities, and if so whether or not Banco Santander will elect to exercise such option to redeem the senior non preferred debt securities or any prior consent of the Relevant Resolution Authority, if required, will be given.

Risks Related to the Subordinated Debt Securities

Banco Santander’s obligations under the subordinated debt securities of any series are subordinated to existing and future senior indebtedness.

Banco Santander’s obligations under the subordinated debt securities of any series will be unsecured and subordinated and will rank junior in priority of payment to all unsubordinated obligations of Banco Santander and to all subordinated obligations of Banco Santander not qualifying as Tier 1 or Tier 2 Capital. Although subordinated debt securities may pay a higher rate of interest than comparable debt securities which are not

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subordinated, there is a greater risk that holders of the subordinated debt securities of any series will lose all or some of their investment should Banco Santander become (i) subject to resolution under the BRRD (as implemented through Law 11/2015 and RD 1012/2015) and the subordinated debt securities of any series become subject to the application of the Spanish Bail-in Power or Non-Viability Loss Absorption or (ii) insolvent.

The subordinated debt securities provide for limited events of default.

Holders have no ability to accelerate the maturity of their subordinated debt securities. The terms and conditions of the subordinated debt securities do not provide for any events of default, except in the case that an order is made by any competent court commencing insolvency proceedings against Banco Santander or for its winding up or liquidation. Accordingly, in the event that any payment on the subordinated debt securities of any series is not made when due, each holder of such series will have a claim only for amounts then due and payable on their subordinated debt securities.

The subordinated debt securities of any series may be subject to substitution and/or variation without a holder’s consent

Subject as provided herein, in particular under “Description of Debt Securities—Substitution and Variation”, if a Capital Disqualification Event or a tax event that would entitle Banco Santander to redeem the debt securities as set forth under “Description of Debt Securities—Redemption and Repurchase—Early Redemption for Taxation Reasons” occurs, Banco Santander may, at its option, and without the consent or approval of the holders of the subordinated debt securities of such series, elect either (i) to substitute all (but not some only) of the subordinated debt securities of such series or (ii) to modify the terms of all (but not some only) of the subordinated debt securities of such series, in each case so that they are substituted for, or varied to, become, or remain, Qualifying Notes. While Qualifying Notes generally must contain terms that are materially no less favorable to holders of the subordinated debt securities of such series as the original terms of the subordinated debt securities of such series, there can be no assurance that the terms of any Qualifying Notes will be viewed by the market as equally favorable, or that the Qualifying Notes will trade at prices that are equal to the prices at which the subordinated debt securities of such series would have traded on the basis of their original terms.

Further, prior to the making of any such substitution or variation, Banco Santander, shall not be obliged to have regard to the tax position of individual holders of the subordinated debt securities of such series or to the tax consequences of any such substitution or variation for any such individual holder. No holder of the subordinated debt securities of such series shall be entitled to claim, whether from the Trustee, Banco Santander, or any other person, any indemnification or payment in respect of any tax consequence of any such substitution or variation upon an individual holder of the subordinated debt securities of such series.

Risks Relating to the Contingent Convertible Capital Securities

The contingent convertible capital securities of any series are subject to certain provisions of the laws of the Kingdom of Spain and their official interpretation, which may change and have a material adverse effect on the terms and market value of the contingent convertible capital securities of such series.

Changes in the laws of Spain or their official interpretation by regulatory authorities such as the Bank of Spain or the European Central Bank after the date hereof may affect the rights and effective remedies of holders of any series of contingent convertible capital securities as well as the market value of the contingent convertible capital securities of such series.

Such changes in law may include changes in statutory, tax and regulatory regimes during the life of the contingent convertible capital securities of any series, or changes that could have a significant impact on the

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future legal entity structure, business mix (including a potential exit of certain business activities), management of the Group, and use of capital and requirements for loss-absorbing capacity within the Group, which may have an adverse effect on investment in the contingent convertible capital securities of such series.

Any such changes (including those which may result from the publication of the technical standards which interpret CRR) could impact the calculation of the CET1 ratio or the CET1 Capital of Banco Santander or the Group or the Risk Weighted Assets Amount. Furthermore, because the occurrence of the Trigger Event and restrictions on Distributions where the Maximum Distributable Amount depends, in part, on the calculation of these ratios and capital measures, any change in Spanish law or their official interpretation by regulatory authorities that could affect the calculation of such ratios and measures could also affect the determination of whether the Trigger Event has actually occurred and/or whether Distributions on the contingent convertible capital securities are subject to restrictions.

Such calculations may also be affected by changes in applicable accounting rules (including IFRS 9), the accounting policies of Banco Santander and the Group and the application by Banco Santander and the Group of these policies. Any such changes, including changes over which Banco Santander or the Group has a discretion, may have a material adverse impact on the reported financial position of Banco Santander or the Group and accordingly may give rise to the occurrence of the Trigger Event in circumstances where such Trigger Event may not otherwise have occurred, notwithstanding the adverse impact this will have for holders of any series of contingent convertible capital securities.

Furthermore, any change in the laws or regulations of Spain, Applicable Banking Regulations or any change in the application or official interpretation thereof may in certain circumstances result in Banco Santander having the option to redeem the contingent convertible capital securities of any series in whole but not in part. In any such case, the contingent convertible capital securities of such series would cease to be outstanding, which could materially and adversely affect investors and frustrate investment strategies and goals.

Such legislative and regulatory uncertainty could affect an investor’s ability to value the contingent convertible capital securities accurately and therefore affect the market price of the contingent convertible capital securities of such series given the extent and impact on the contingent convertible capital securities of such series of one or more regulatory or legislative changes.

Banco Santander will be restricted from making payments of Distributions on the contingent convertible capital securities in certain circumstances, in which case Banco Santander will cancel such Distributions, and holders of contingent convertible capital securities of any series may not be able to anticipate whether or not Banco Santander will cancel such Distributions.

Under CRD IV and CRR, institutions must comply with a number of capital requirements. As discussed above, in accordance with Article 48 of Law 10/2014, Article 73 of Royal Decree 84/2015 and Rule 24 of Bank of Spain Circular 2/2016 (which implement Article 141 of CRD IV Directive), an entity not meeting its “combined buffer requirement” must calculate its Maximum Distributable Amount and, until the Maximum Distributable Amount has been calculated and communicated to the Bank of Spain, that entity shall not make any discretionary payments. Following such calculation, any discretionary payments by that entity (including the payment of any Distributions on the contingent convertible capital securities) will be subject to the Maximum Distributable Amount so calculated.

In accordance with Article 73 of Royal Decree 84/2015 and Rule 24 of the Bank of Spain Circular 2/2016, restrictions of discretionary payments will be scaled according to the extent of the breach of the “combined buffer requirement” and calculated as a percentage of the profits of the institution generated since the last annual decision on the distribution of profits. Such calculation will result in a Maximum Distributable Amount in each relevant period. As an example, the scaling is such that in the bottom quartile of the “combined buffer requirement”, no discretionary payments will be permitted to be made. As a consequence, in the event of breach

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of the combined buffer requirement (including where additional capital requirements are imposed that have the result of increasing the regulatory minimum required under CRD IV) it may be necessary to reduce discretionary payments (in whole or in part), including payments of Distributions in respect of the contingent convertible capital securities.

There are a number of factors that make the determination and application of the Maximum Distributable Amount particularly complex, including the following:

These and other possible interpretation issues (including any changes in the Applicable Banking Regulations) make it difficult to determine how the Maximum Distributable Amount will apply as a practical matter to limit Distributions on the contingent convertible capital securities. This uncertainty and the resulting complexity may adversely impact the market price and liquidity of the contingent convertible capital securities.

Whether Distributions on the contingent convertible capital securities may be subject to a Maximum Distributable Amount as a result of a breach of the “combined buffer requirement” will depend, among other things, on the applicable capital requirements, the amount of CET1 Capital and the “distributable profits” of Banco Santander and/or the Group, as applicable, which can be affected by, among other things, regulatory developments, management decisions taken by the Group, and other such considerations similar to those discussed above in relation to the circumstances that may give rise to a Trigger Event. See “—The circumstances that may give rise to the Trigger Event are inherently unpredictable and may be caused by factors outside of Banco Santander’s control. Banco Santander has no obligation to operate its business in such a way, or take any mitigating actions, to maintain or restore its CET1 ratio to avoid a Trigger Event and any actions Banco Santander may take now or in the future could result in its CET1 ratio failing” below. The holders of the contingent convertible capital securities will not have any claim against Banco Santander or any other member of the Group in relation to any such decision.

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Furthermore, any determination of the capital of Banco Santander and/or the Group and the compliance by Banco Santander and/or the Group with the respective capital requirements that may be imposed from time to time will involve consideration of a number of factors any one or combination of which may not be easily observable or capable of calculation by the holders of the contingent convertible capital securities and some of which may also be outside of the control of Banco Santander and/or the Group. The risk of any cancellation (in whole or in part) of Distributions on the contingent convertible capital securities may not, therefore, be possible to predict in advance and any such cancellation of Distributions on the contingent convertible capital securities could occur without warning.

Finally, as explained above, a breach of the “combined buffer requirement” when considered in addition to the applicable minimum TLAC/MREL requirements (Article 16bis of Law 11/2015) or a breach of the leverage ratio buffer (Article 48ter of Law 10/2014) could also result in a requirement to determine a Maximum Distributable Amount.

Under the terms of the contingent convertible capital securities of any series, holders of contingent convertible capital securities of such series shall have agreed to be bound by the exercise of any Spanish Bail-in Power or Non-Viability Loss Absorption by the Relevant Resolution Authority.

Pursuant to Article 46 of Law 11/2015, which implements Article 55 of the BRRD and Article 52 of CRR, subject to limited exceptions, unsecured liabilities of an institution governed by the laws of a third-country (which include the contingent convertible capital securities of any series) must contain a contractual acknowledgment whereby the holders recognize that such liability may be subject to the Spanish Bail-in Power and Non-Viability Loss Absorption and agree to be bound by the exercise of those powers by the Relevant Resolution Authority.

Notwithstanding any other term of the contingent convertible capital securities of any series or any other agreements, arrangements, or understandings between Banco Santander and any holder of the contingent convertible capital securities of any series, by its acquisition of the contingent convertible capital securities of any series, each holder (which, for the purposes of this clause, includes each holder of a beneficial interest in the contingent convertible capital securities of any series) acknowledges, accepts, consents to and agrees to be bound by the exercise of any Spanish Bail-in Power or any Non-Viability Loss Absorption by the Relevant Resolution Authority that may result in the write-down or cancellation of all or a portion of the Amounts Due on the contingent convertible capital securities and/or the conversion of all or a portion of the Amounts Due on the contingent convertible capital securities into shares or other securities or other obligations of Banco Santander or another person, including by means of a variation to the terms of the contingent convertible capital securities to give effect to the exercise by the Relevant Resolution Authority of such powers. Each holder of the contingent convertible capital securities further acknowledges and agrees that the rights of the holders of the contingent convertible capital securities are subject to—, and will be varied, if necessary, so as to give effect to—, the exercise of any Spanish Bail-in Power or Non-Viability Loss Absorption by the Relevant Resolution Authority.

Any Spanish Bail-in Power or Non-Viability Loss Absorption may be exercised in such a manner as to result in holders of contingent convertible capital securities of the relevant series losing the value of all or a part of their investment in the contingent convertible capital securities of such series or receiving a different security from the contingent convertible capital securities of such series, which may be worth significantly less than the contingent convertible capital securities of such series and which have significantly fewer protections than those typically afforded to debt securities. Moreover, the Relevant Resolution Authority may exercise its authority to implement the Spanish Bail-in Power or Non-Viability Loss Absorption without providing any advance notice to the holders of the contingent convertible capital securities of such series. For more information, see “Description of Contingent Convertible Capital Securities—Agreement and Acknowledgement with Respect to the Exercise of the Bail-in Power”.

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Holders of contingent convertible capital securities of any series are likely to have limited rights to challenge the exercise of the Spanish Bail-in Power or Non-Viability Loss Absorption by the Relevant Resolution Authority.

Law 11/2015 contains certain safeguards for creditors in respect of the application of the capital instruments write-down and conversion power and the bail-in tool.

With respect to the capital instruments write-down and conversion power, the Relevant Resolution Authority will exercise such power in accordance with the priority of claims under normal insolvency proceedings such that Common Equity Tier 1 Instruments will be written down before Additional Tier 1 Instruments and Tier 2 Instruments, successively, are written down or converted into Common Equity Tier 1 Instruments.

In accordance with Article 48 of Law 11/2015 (and subject to any exclusions that may be applied by the Relevant Resolution Authority under Article 43 of Law 11/2015), in the case of any application of the Spanish Bail-in Power, the sequence of any resulting write-down or conversion by the Relevant Resolution Authority shall be as follows: (i) Common Equity Tier 1 Instruments; (ii) the principal amount of Additional Tier 1 Instruments, (iii) the principal amount of Tier 2 Instruments; (iv) the principal amount of other subordinated claims that do not qualify as Additional Tier 1 Instruments or Tier 2 Instruments; and (v) the principal or outstanding amount of the eligible liabilities (pasivos admisibles) prescribed in Article 41 of Law 11/2015. Any application of the Spanish Bail-in Power under the BRRD shall be in accordance with the hierarchy of claims in normal insolvency proceedings (unless otherwise provided by applicable banking regulations).

Notwithstanding the above, there may be limited protections, if any, that will be available to holders of securities subject to the Spanish Bail-in Power (including the contingent convertible capital securities of any series) or to Non-Viability Loss Absorption and to the broader resolution powers of the Relevant Resolution Authority. Accordingly, holders of contingent convertible capital securities of any series may have limited or circumscribed rights to challenge any decision of the Relevant Resolution Authority to exercise its Spanish Bail-in Power or Non-Viability Loss Absorption.

The circumstances under which the Relevant Resolution Authority would exercise its Spanish Bail-in Power or Non-Viability Loss Absorption are currently uncertain.

There remains uncertainty as to how or when the Spanish Bail-in Power or Non-Viability Loss Absorption may be exercised and how it would affect the Group and the holders of contingent convertible capital securities of any series. The exercise of the Spanish Bail-in Power and/or Non-Viability Loss Absorption by the Relevant Resolution Authority is likely to be inherently unpredictable and may depend on a number of factors which may be outside of Banco Santander’s control. Although there are proposed pre-conditions for the exercise of the Spanish Bail-in Power or Non-Viability Loss Absorption, there remains uncertainty regarding the specific factors which the Relevant Resolution Authority would consider in deciding whether to exercise the Spanish Bail-in Power or Non-Viability Loss Absorption with respect to the financial institution and/or securities issued or guaranteed by that institution. In addition, as the Relevant Resolution Authority will retain an element of discretion, holders of contingent convertible capital securities of any series may not be able to refer to publicly available criteria in order to anticipate a potential exercise of any such Spanish Bail-in Power or Non-Viability Loss Absorption. Because of this inherent uncertainty, it will be difficult to predict when, if at all, the exercise of any such powers, may occur which would result in a Liquidation Preference write off or conversion to equity. The uncertainty may adversely affect the value of holders’ investments in the contingent convertible capital securities of any series and the price and trading behavior of the contingent convertible capital securities of any series. may be affected by the threat of a possible exercise of any power under Law 11/2015 (including any early intervention measure before any resolution) or any suggestion of such exercise, even if the likelihood of such exercise is remote. Moreover, the Relevant Resolution Authority may exercise any such power without providing any advance notice to the holders of debt securities.

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The contingent convertible capital securities are irrevocably and mandatorily convertible into newly issued Common Shares in certain prescribed circumstances, and as a result, holders of contingent convertible capital securities of any series could lose all or part of their investment in the contingent convertible capital securities of such series.

Upon the occurrence of the Trigger Event, the contingent convertible capital securities of any series will be irrevocably and mandatorily (and without any requirement for the consent or approval of holders of the contingent convertible capital securities of such series) converted in whole but not in part (which calculation is made by Banco Santander and shall be binding on the holders of the contingent convertible capital securities of such series) into newly issued Common Shares and the holders of the contingent convertible capital securities of such series will lose all of their claims for payment under the contingent convertible capital securities and receive Common Shares instead (which are more deeply subordinated). Because the Trigger Event will occur when the CET1 ratio of Banco Santander and/or the Group, as applicable, will have deteriorated significantly, the resulting Trigger Event will likely be accompanied by a prior deterioration in the market price of the Common Shares, which may be expected to continue after announcement of the Trigger Event.

Therefore, in the event of the occurrence of the Trigger Event, the Current Market Price of a Common Share may be below the Floor Price and investors could receive Common Shares at a time when the market price of the Common Shares is considerably less than the Conversion Price. In addition, there may be a delay in a holder of contingent convertible capital securities receiving its Common Shares following the Trigger Event, during which time the market price of the Common Shares may fall further. As a result, the value of the Common Shares received on conversion following the Trigger Event could be substantially lower than the price paid for the contingent convertible capital securities at the time of their purchase.

Following the conversion of contingent convertible capital securities into Common Shares, the principal amount of the contingent convertible capital securities will not be restored in any circumstances (including where the relevant Trigger Event ceases to continue), no further interest will accrue or be payable on the contingent convertible capital securities at any time thereafter and the holders of the contingent convertible capital securities shall have no recourse to Banco Santander for any further payment in respect of the contingent convertible capital securities (subject to the right of the holders to receive the relevant number of Common Shares from the Settlement Shares Depository).

If a Trigger Event occurs, holders of the contingent convertible capital securities will only have the claims under their Common Shares. Claims in respect of Common Shares would be the most junior-ranking in the event of a winding-up or liquidation of Banco Santander. Claims in respect of Common Shares are not for a fixed principal amount, but rather are limited to a share of the surplus assets (if any) remaining following payment of all amounts due in respect of the liabilities of Banco Santander.

Accordingly, an investor in the contingent convertible capital securities of any series faces almost the same risk of loss as an investor in the Common Shares in the event of the Trigger Event. See also “—Holders of the contingent convertible capital securities of any series will bear the risk of fluctuations in the price of the Common Shares and/or movements in any ratio that could give rise to the occurrence of the Trigger Event. Holders of the contingent convertible capital securities of any series will also bear the risk of changes in the U.S. dollar and euro exchange rate.” below.

A capital reduction may take place in accordance with the Spanish Companies Act.

In accordance with Article 418.3 of the Spanish Companies Act, in the event that Banco Santander intends to approve a capital reduction by reimbursement of contributions (restitución de aportaciones) to shareholders, holders of contingent convertible capital securities of any series will be entitled to convert the contingent convertible capital securities of such series into Common Shares at the applicable Conversion Price prior to the

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execution of such capital reduction. A resolution of capital reduction for the redemption of any Common Shares previously repurchased by Banco Santander will not be considered a capital reduction for these purposes.

The circumstances that may give rise to the Trigger Event are inherently unpredictable and may be caused by factors outside of Banco Santander’s control. Banco Santander has no obligation to operate its business in such a way, or take any mitigating actions, to maintain or restore its CET1 ratio to avoid a Trigger Event and any actions Banco Santander may take now or in the future could result in its CET1 ratio failing.

The occurrence of the Trigger Event is inherently unpredictable and depends on a number of factors, many of which are outside of Banco Santander’s control. For example, the occurrence of one or more of the risks described under “Risk Factors” in Banco Santander’s Annual Report on Form 20-F for the year ended December 31, 2022, or the deterioration of the circumstances described therein, could substantially increase the likelihood of the occurrence of the Trigger Event. Furthermore, the occurrence of the Trigger Event depends, in part, on the calculation of the CET1 ratio, which can be affected, among other things, by the growth of the business and future earnings of Banco Santander and/or the Group, as applicable; expected payments by Banco Santander in respect of dividends and Distributions and other equivalent payments in respect of instruments ranking junior to the contingent convertible capital securities of any series as well as other Parity Securities; regulatory changes (including possible changes in regulatory capital definitions, calculations and risk weighted assets), changes in Banco Santander’s structure or organization and Banco Santander’s ability to actively manage the risk weighted assets of Banco Santander and the Group and changes in applicable accounting rules, or any changes to regulatory adjustments which modify the regulatory capital impact of accounting rules.

The CET1 ratio of Banco Santander and/or the Group at any time may also depend on decisions taken by the Group in relation to its businesses and operations, as well as the management of its capital position. Banco Santander will have no obligation to consider the interests of the holders of the contingent convertible capital securities in connection with the strategic decisions of the Group, including in respect of capital management. Holders of the contingent convertible capital securities will not have any claim against Banco Santander or any other member of the Group relating to decisions that affect the business and operations of the Group, including its capital position, regardless of whether they result in the occurrence of a Trigger Event. Such decisions could cause holders of the contingent convertible capital securities to lose all or part of the value of their investment in the contingent convertible capital securities.

In addition, since the relevant Regulator may require Banco Santander to calculate the CET1 ratio at any time, the Trigger Event could occur at any time. Due to the inherent uncertainty in determining whether the Trigger Event may exist, it will be difficult to predict when, if at all, the contingent convertible capital securities of any series will be converted into Common Shares. Accordingly, trading behavior in respect of the contingent convertible capital securities of any series is not necessarily expected to follow trading behavior associated with other types of convertible or exchangeable securities. Any indication that Banco Santander and/or the Group, as applicable, is trending towards the Trigger Event can be expected to have an adverse effect on the market price and liquidity of the contingent convertible capital securities of such series and on the price of the Common Shares. Under such circumstances, investors may experience difficulty selling or may not be able to sell the contingent convertible capital securities of such series or at prices comparable to other similar yielding instruments. In addition, the risk of Trigger Conversion could drive down the price of Banco Santander’s Common Shares and therefore have a material adverse effect on the market value of any Common Shares received upon Trigger Conversion.

Holders of the contingent convertible capital securities of any series will bear the risk of fluctuations in the price of the Common Shares and/or movements in any ratio that could give rise to the occurrence of the Trigger Event. Holders of the contingent convertible capital securities of any series will also bear the risk of changes in the U.S. dollar and euro exchange rate.

The market price of the contingent convertible capital securities of any series is expected to be affected by fluctuations in the market price of the Common Shares, in particular if at any time there is a significant

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deterioration in any of the ratios by reference to which the determination of any occurrence of the Trigger Event is made, and it is impossible to predict whether the price of the Common Shares will rise or fall. Market prices of the Common Shares will be influenced by, among other things, the financial position of the Group, the results of operations and political, economic, financial and other factors. Any decline in the market price of the Common Shares or any indication that a ratio is trending towards occurrence of the Trigger Event may have an adverse effect on the market price of the contingent convertible capital securities of any series. The level of each ratio specified in the definition of Trigger Event may also significantly affect the market price of the contingent convertible capital securities of any series and/or the Common Shares.

Fluctuations in the market price of the Common Shares between the Trigger Event Notice Date and the Conversion Settlement Date may also further affect the value to a holder of any Common Shares delivered to that holder on the Conversion Settlement Date.

In addition, as Banco Santander’s Common Shares are denominated and trade in euros, the market price of the contingent convertible capital securities of any series may also be affected by fluctuations in the U.S. dollar and euro exchange rate due to the contingent convertible capital securities of such being denominated in U.S. dollars. Upon a Trigger Conversion, the contingent convertible capital securities of such series will convert into Common Shares, or if the holder elects, ADSs, at the Conversion Price. Because the Trigger Conversion will occur when the CET1 ratio of Banco Santander will have deteriorated significantly, the resulting Trigger Conversion will likely be accompanied by a prior deterioration in the market price of the Common Shares, which may be expected to continue after announcement of the Trigger Conversion. Therefore, in the event of the occurrence of the Trigger Event, the Current Market Price of a Common Share, converted into U.S. dollars at the Prevailing Rate, may be below the Floor Price and investors could receive Common Shares at a time when the market price of the Common Shares is considerably less than the Conversion Price. Fluctuations in the U.S. dollar and euro exchange rate could therefore also affect the realizable value of the Common Shares.

Furthermore, there may be a delay in holders of contingent convertible capital securities of any series receiving their Common Shares or ADSs, as applicable, following a Trigger Event, during which time the market price of the Common Shares and/or ADSs (as the case may be) or the exchange rate of euro against the U.S. dollar may further decline. No interest or other compensation is payable in the event of a loss by holders of contingent convertible capital securities of any series due to foreign currency conversions.

The contingent convertible capital securities of any series have no scheduled maturity and no fixed redemption date and holders of contingent convertible capital securities of any series do not have the right to cause the contingent convertible capital securities of such series to be redeemed or otherwise accelerate the repayment of the Liquidation Preference of the contingent convertible capital securities except in very limited circumstances.

The contingent convertible capital securities of any series are perpetual securities and have no fixed maturity date or fixed redemption date. Banco Santander is under no obligation to redeem the contingent convertible capital securities of any series at any time and the holders of contingent convertible capital securities of such series have no right to call for their redemption at any time. Although under certain circumstances as described under “Description of Contingent Convertible Capital Securities—Redemption and Repurchase” Banco Santander may redeem the contingent convertible capital securities of any series, Banco Santander is under no obligation to do so and holders of contingent convertible capital securities of any series have no right to call for their redemption.

The contingent convertible capital securities of any series may be redeemable at the option of Banco Santander.

The contingent convertible capital securities of any series may be redeemable at the option of Banco Santander, in whole but not in part, subject to the prior consent of the relevant Regulator, on the dates to be

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specified in the relevant prospectus supplement, at the Redemption Price per contingent convertible capital security and otherwise in accordance with Applicable Banking Regulations then in effect. Under the CRR, the relevant Regulator will give its consent to a redemption of the contingent convertible capital securities of any series in such circumstances provided that either of the following conditions is met:

(i) on or before such redemption of the contingent convertible capital securities of such series, Banco Santander replaces the contingent convertible capital securities of such series with instruments qualifying as Tier 1 Capital of an equal or higher quality on terms that are sustainable for the income capacity of Banco Santander; or

(ii) Banco Santander has demonstrated to the satisfaction of the relevant Regulator that its Tier 1 Capital and Tier 2 Capital and its eligible liabilities would, following such redemption, exceed the requirements laid down in CRD IV and BRRD by a margin that the relevant Regulator considers necessary.

The contingent convertible capital securities of any series are also redeemable on or after the relevant issue date at the option of Banco Santander in whole but not in part, at any time, at the Redemption Price (subject to the prior consent of the relevant Regulator and otherwise in accordance with Applicable Banking Regulations then in force) if there is a Capital Event or a Tax Event.

It is not possible to predict whether or not a change in the laws or regulations of Spain, Applicable Banking Regulations or the application or official interpretation thereof, will occur and so lead to the circumstances in which Banco Santander is able to elect to redeem the contingent convertible capital securities of any series, and if so whether or not Banco Santander will elect to exercise such option to redeem the contingent convertible capital securities of such series. There can be no assurances that, in the event of any such early redemption, holders of contingent convertible capital securities of any series will be able to reinvest the proceeds at a rate that is equal to the return on the contingent convertible capital securities of such series.

In the case of any early redemption of the contingent convertible capital securities of any series at the option of Banco Santander, Banco Santander may exercise this option when its funding costs are lower than the Distribution Rate at which Distributions are then payable in respect of the contingent convertible capital securities of such series. In these circumstances, the rate at which holders of contingent convertible capital securities of such series are able to reinvest the proceeds of such redemption is unlikely to be as high as, and may be significantly lower than, that Distribution Rate.

In addition, the redemption feature of the contingent convertible capital securities of any series may affect their market value. During any period when Banco Santander has the right to elect to redeem the contingent convertible capital securities of such series, the market value of the contingent convertible capital securities of any series is unlikely to rise substantially above the price at which they can be redeemed. This may also be true prior to such period.

Payments of Distributions on the contingent convertible capital securities of any series are payable in Banco Santander’s sole and absolute discretion and Banco Santander may (and in certain circumstances will have no choice but to) cancel any Distributions in whole or in part at any time. Unpaid Distributions are not cumulative or payable at any time thereafter and holders of contingent convertible capital securities of such series shall have no rights thereto.

The contingent convertible capital securities of any series accrue Distributions as further described “Description of Contingent Convertible Capital Securities—Distributions”, but Banco Santander may elect, in its sole and absolute discretion, to cancel the payment of any Distribution in whole or in part at any time that it deems necessary or desirable, and for any reason and without any restriction on it thereafter. Payments of Distributions in any financial year of Banco Santander shall be made only out Available Distributable Items (as defined below). To the extent that:

(i) Banco Santander has insufficient Available Distributable Items to make Distributions on the contingent convertible capital securities of any series scheduled for payment in the then current financial year and any

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equivalent payments scheduled to be made in the then current financial year in respect of any other Parity Securities and Common Equity Tier 1 Instruments then outstanding, in each case excluding any portion of such payments already accounted for in determining the Available Distributable Items; and/or

(ii) the relevant Regulator, in accordance with Applicable Banking Regulations, requires Banco Santander to cancel the relevant Distribution in whole or in part,

then Banco Santander will, without prejudice to the right above to cancel the payment of all such Distributions on the contingent convertible capital securities of such series, make partial or, as the case may be, no payment of the relevant Distribution on the contingent convertible capital securities of such series.

The level of Banco Santander’s Available Distributable Items may also be affected by changes to accounting rules, regulation or the requirements and expectations of applicable regulatory authorities. Any such potential changes could adversely affect the Banco Santander’s Available Distributable Items in the future.

Banco Santander’s Available Distributable Items, and therefore the Banco Santander’s ability to make Distributions under the contingent convertible capital securities, may be adversely affected by the performance of the business of the Group in general, factors affecting its financial position (including capital and leverage), the economic environment in which the issuer and the Group operates and other factors outside of Banco Santander’s control. In addition, adjustments to earnings, as determined by the management of Banco Santander, may fluctuate significantly and may materially adversely affect Available Distributable Items.

In addition, no payment will be made on the contingent convertible capital securities of any series (whether by way of a repayment of the Liquidation Preference, the payment of any Distribution or otherwise) if and to the extent that such payment would cause a breach of any regulatory restriction or prohibition on payments on Additional Tier 1 Instruments pursuant to Applicable Banking Regulations, including, without limitation (i) any such restriction or prohibition relating to any Maximum Distributable Amount under Article 48 of Law 10/2014 and any provisions implementing such Article, Article 16 bis of Law 11/2015 and any other provision of Spanish law transposing or implementing Article 141(2) of the CRD IV, (ii) any restrictions that could be imposed if a G-SII does not meet at the leverage ratio buffer under Article 48ter of Law 10/2014 or (iii) any other restrictions contained in the Applicable Banking Regulations.

There can, therefore, be no assurances that a holder of contingent convertible capital securities of any series will receive payments of Distributions in respect of the contingent convertible capital securities of such series. Unpaid Distributions are not cumulative or payable at any time thereafter and, accordingly, if any Distribution (or part thereof) is not made in respect of the contingent convertible capital securities of any series as a result of any requirement for, or election of, Banco Santander to cancel such Distributions then the right of the holders of contingent convertible capital securities of such series to receive the relevant Distribution (or part thereof) in respect of the relevant Distribution Period will be extinguished and Banco Santander will have no obligation to pay such Distribution (or part thereof) or to pay any interest thereon, whether or not Distributions on the contingent convertible capital securities of any series are paid in respect of any future Distribution Period.

As set forth in the terms of the contingent convertible capital securities, if practicable, Banco Santander will provide notice of any cancellation or deemed cancellation of Distributions. However, the cancellation of any Distributions on the contingent convertible capital securities could occur without prior notice or warning. Any such cancellation or any perceived risk that Distributions may be cancelled may have a negative impact on the value of the contingent convertible capital securities.

No such election to cancel the payment of any Distribution (or part thereof) or non-payment of any Distribution (or part thereof) will constitute an event of default, a breach of any obligations of Banco Santander under the contingent convertible capital securities of such series, or the occurrence of any event related to the insolvency of Banco Santander or entitle holders to take any action to cause the liquidation, dissolution or winding up of Banco Santander.

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If, as a result of any of the conditions set out above being applicable, only part of the Distributions under the contingent convertible capital securities of any series may be paid, Banco Santander may proceed, in its sole discretion, to make such partial Distributions under the contingent convertible capital securities of such series.

As a holding company, the level of Banco Santander’s Available Distributable Items is affected by a number of factors and insufficient Available Distributable Items may restrict Banco Santander’s ability to make Distributions on the contingent convertible capital securities of any series.

As a holding company of other operating companies, the level of Banco Santander’s Available Distributable Items is affected in part by a number of factors, including Banco Santander’s ability to receive funds, directly or indirectly, from Banco Santander’s operating subsidiaries in a manner which creates Available Distributable Items. Consequently, Banco Santander’s future Available Distributable Items, and therefore Banco Santander’s ability to make payments of Distributions, are a function of Banco Santander’s existing Available Distributable Items, Banco Santander’s future profitability and performance and the ability of Banco Santander’s operating subsidiaries to distribute or dividend profits up the Group structure to Banco Santander. In addition, Banco Santander’s Available Distributable Items will also be reduced by the redemption of equity instruments and the servicing of other debt and equity instruments and there are no restrictions on Banco Santander’s ability to make payments on, or redemptions of, Parity Securities or junior securities even if that results in Banco Santander’s Available Distributable Items not being sufficient to make a scheduled Distribution on the contingent convertible capital securities of any series.

The ability of Banco Santander’s subsidiaries to pay dividends and Banco Santander’s ability to receive Distributions and other payments from Banco Santander’s investments in other entities is subject to applicable local laws and other restrictions, including their respective regulatory, capital and leverage requirements, statutory reserves, financial and operating performance and applicable tax laws, and any changes thereto. These laws and restrictions could limit the payment of dividends, Distributions and other payments to Banco Santander by Banco Santander’s subsidiaries, which could in time restrict Banco Santander’s ability to fund other operations or to maintain or increase Banco Santander’s Available Distributable Items. The level of Banco Santander’s Available Distributable Items may be further affected by changes to regulations or the requirements and expectations of applicable regulatory authorities. In particular, local capital or ring-fencing requirements outside Spain could adversely affect Banco Santander’s Available Distributable Items in the future.

Further, Banco Santander’s Available Distributable Items may be adversely affected by the performance of Banco Santander’s business in general, changes in its organizational structure, factors affecting its financial position (including capital and leverage), the economic environment in which it operates and other factors outside of its control. In addition, adjustments to earnings, as determined by the management of Banco Santander, may fluctuate significantly and may materially adversely affect Available Distributable Items.

Banco Santander shall not make a payment of Distributions on the contingent convertible capital securities of any series on any Distribution Payment Date (and such Distribution shall therefore be deemed to have been cancelled and thus shall not be due and payable on such Distribution Payment Date) if the level of Available Distributable Items is insufficient to fund that payment. Distributions that are deemed cancelled shall not be due and shall not accumulate or be payable at any time thereafter and holders of contingent convertible capital securities of any series shall have no right thereto. See “—Payments of Distributions on the contingent convertible capital securities of any series are payable in Banco Santander’s sole and absolute discretion and Banco Santander may (and in certain circumstances will have no choice but to) cancel any Distributions in whole or in part at any time. Unpaid Distributions are not cumulative or payable at any time thereafter and holders of contingent convertible capital securities of such series shall have no rights thereto.”

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The contingent convertible capital securities of any series do not contain events of default and the remedies available to holders under the convertible capital securities of any series are limited.

The terms of the convertible capital securities of any series do not provide for any events of default. Banco Santander is entitled to cancel the payment of any Distribution in whole or in part at any time (see “—Payments of Distributions on the contingent convertible capital securities of any series are payable in Banco Santander’s sole and absolute discretion and Banco Santander may (and in certain circumstances will have no choice but to) cancel any Distributions in whole or in part at any time. Unpaid Distributions are not cumulative or payable at any time thereafter and holders of contingent convertible capital securities of such series shall have no rights thereto”) and such cancellation will not constitute any event of default or similar event or entitle holders of convertible capital securities of such series to take any related action against Banco Santander. Furthermore, the Trigger Conversion will not constitute an event of default or the occurrence of any event related to the insolvency of Banco Santander or entitle holders of convertible capital securities of such series to take any action to cause the liquidation, dissolution or winding-up of Banco Santander. If Common Shares are not issued and delivered following the Trigger Event, then on a liquidation, dissolution or winding-up of Banco Santander the claim of a holder of convertible capital securities of any series will not be in respect of the Liquidation Preference of its contingent convertible capital securities of such series but will be an entitlement to receive out of the relevant assets a monetary amount equal to that which holders of the contingent convertible capital securities of such series would have received on any distribution of the assets of Banco Santander if such Trigger Conversion had taken place immediately prior to such liquidation, dissolution or winding-up.

Holders of the contingent convertible capital securities of any series only have a limited ability to cash in their investment in the contingent convertible capital securities of such series.

Holders of convertible capital securities of any series have no ability to require Banco Santander to redeem the convertible capital securities of such series. Banco Santander has the option to redeem the convertible capital securities of any series in certain circumstances (see “—The contingent convertible capital securities of any series may be redeemable at the option of Banco Santander” above). The ability of Banco Santander to redeem or repurchase the contingent convertible capital securities of any series is subject to Banco Santander satisfying certain conditions as described under “Description of Contingent Convertible Capital Securities—Redemption and Repurchase”. There can be no assurance that holders of convertible capital securities of any series will be able to reinvest the amount received upon redemption and/or repurchase at a rate that will provide the same rate of return as their investment in the convertible capital securities of such series.

Therefore, holders of the contingent convertible capital securities of any series have no ability to cash in their investment, except:

(i) if Banco Santander exercises its rights to redeem or repurchase the contingent convertible capital securities of such series in accordance with “Description of Contingent Convertible Capital Securities—Redemption and Repurchase”; or

(ii) by selling the contingent convertible capital securities of such series or, following the occurrence of the Trigger Event and the issue and delivery of Common Shares or, if the holder elects, ADSs, in accordance with “Description of Contingent Convertible Capital Securities—Conversion Upon Trigger Event”, their Common Shares or ADSs, provided a secondary market exists at the relevant time for the contingent convertible capital securities of such series, the Common Shares or the ADSs.

Holders of the contingent convertible capital securities of any series have limited anti-dilution protection.

The number of Common Shares to be issued and delivered on Trigger Conversion in respect of each contingent convertible capital security of any series shall be determined by dividing the Liquidation Preference of such contingent convertible capital security by the Conversion Price in effect on the Trigger Event Notice Date. The Conversion Price will be, if the Common Shares are then admitted to trading on a Relevant Stock

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Exchange, the higher of: (a) the Current Market Price of a Common Share, converted into U.S. dollars at the Prevailing Rate, (b) the Floor Price and (c) the nominal value of a Common Share at the time of conversion, converted into U.S. dollars at the Prevailing Rate, or, if the Common Shares are not then admitted to trading on a Relevant Stock Exchange, the higher of (b) and (c) above. See “Description of Contingent Convertible Capital Securities—Conversion Price” regarding the Conversion Price.

The Floor Price will be adjusted in the event that there is a consolidation, reclassification/redesignation or subdivision affecting the Common Shares, the payment of any Extraordinary Dividends or Non-Cash Dividends, rights issues or grant of other subscription rights or certain other events which affect the Common Shares, but only in the situations and to the extent provided in “Description of Contingent Convertible Capital Securities—Anti-Dilution Adjustment of the Floor Price”. There is no requirement that there should be an adjustment for every corporate or other event that may affect the value of the Common Shares or that, if a holder of contingent convertible capital securities of any series were to have held the Common Shares at the time of such adjustment, the holder of the contingent convertible capital securities of such series would not have benefited to a greater extent.

Furthermore, the relevant indenture does not provide for certain undertakings from Banco Santander which are sometimes included in securities that convert into the ordinary shares of an issuer to protect investors in situations where the relevant conversion price adjustment provisions do not operate to neutralize the dilutive effect of certain corporate events or actions on the economic value of the Conversion Price. For example, the relevant indenture contains neither an undertaking restricting the modification of rights attaching to the Common Shares nor an undertaking restricting issues of new share capital with preferential rights relative to the contingent convertible capital securities of any series.

Further, if Banco Santander issues any Common Shares credited as fully paid to Shareholders by way of capitalization of profits or reserves (including any share premium account or capital redemption reserve), where the Shareholders may elect to receive a Dividend in cash in lieu of such Common Shares and such Dividend does not constitute an Extraordinary Dividend, no conversion price adjustment shall be applicable in accordance with sub-paragraphs (b) and (c) of “Description of Contingent Convertible Capital Securities—Anti-Dilution Adjustment of the Floor Price”, and therefore holders of contingent convertible capital securities of any series will not be protected by anti-dilution measures.

Accordingly, corporate events or actions in respect of which no adjustment to the Floor Price is made may adversely affect the value of the contingent convertible capital securities of any series.

In order to comply with increasing regulatory capital requirements imposed by applicable regulations, Banco Santander may need to raise additional capital. Further capital raisings by Banco Santander could result in the dilution of the interests of the holders of contingent convertible capital securities of any series subject only to the limited anti-dilution protections referred to above.

The obligations of Banco Santander under the contingent convertible capital securities of any series are subordinated to unsubordinated obligations and subordinated obligations senior in right of payment to the contingent convertible capital securities of any series and will be further subordinated upon conversion into Common Shares.

Unless previously converted into Common Shares, the payment obligations of Banco Santander under the contingent convertible capital securities are direct, unconditional, unsecured and subordinated obligations of Banco Santander according to Article 281.1 of the Spanish Insolvency Law and, in accordance with Additional Provision 14.3 of Law 11/2015 but, subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, for so long as the obligations of Banco Santander in respect of the contingent convertible capital securities constitute Additional Tier 1 Instruments, rank (i) pari passu among themselves and with (a) all other subordinated obligations (créditos subordinados) of Banco

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Santander under Additional Tier 1 Instruments and (b) any other subordinated obligations (créditos subordinados) which by law and/or by their terms, to the extent permitted by Spanish law, rank pari passu with Banco Santander’s obligations under Additional Tier 1 Instruments; (ii) junior to (a) any unsubordinated obligations (créditos ordinarios) of Banco Santander, (b) any obligations of Banco Santander in respect of Tier 2 Instruments and (c) any other subordinated obligations (créditos subordinados) which by law and/or by their terms, to the extent permitted by Spanish law, rank senior to Banco Santander’s obligations under Additional Tier 1 Instruments; and (iii) senior to (a) any claims for the liquidation amount of the Common Shares and (b) any other subordinated obligations (créditos subordinados) of Banco Santander which by law and/or by their terms, to the extent permitted by Spanish law, rank junior to Banco Santander’s obligations under Additional Tier 1 Instruments.

Subject to compliance with applicable regulatory requirements, Banco Santander expects from time to time to incur additional indebtedness or other obligations that will constitute senior and other subordinated indebtedness that will rank ahead of the contingent convertible capital securities of any series, and the contingent convertible capital securities of any series do not contain any provisions restricting Banco Santander’s ability or Banco Santander’s subsidiaries from incurring such senior or subordinated indebtedness. Although the contingent convertible capital securities of any series may pay a higher rate of interest than other comparable securities which are not as deeply subordinated, there is a risk that holders of contingent convertible capital securities of such series will lose all or some of their investment should Banco Santander become insolvent since Banco Santander’s assets would be available to pay such amounts only after all of Banco Santander’s senior creditors have been paid in full.

No security or guarantee of whatever kind is, or shall at any time be, provided by Banco Santander or any other person securing the rights of the holders under the contingent convertible capital securities.

Second paragraph of Article 48(7) of BRRD, as implemented in Spain through Additional Provision 14.3 of Law 11/2015, clarified that if an instrument is only partly recognised as an own funds instrument and, in the event of insolvency, the whole instrument shall be treated as a claim resulting from an own funds instrument and shall rank junior to any claim that does not result from an own funds instrument.

In addition, if Banco Santander were wound up, dissolved or liquidated, Banco Santander’s liquidator would first apply the assets of Banco Santander to satisfy all claims of holders of unsubordinated obligations of Banco Santander and other creditors ranking ahead of holders of convertible capital securities of any series. If Banco Santander does not have sufficient assets to settle claims of prior ranking creditors in full, the claims of the holders of convertible capital securities of any series will not be satisfied. Holders of convertible capital securities of any series will share equally in any distribution of assets with the holders of any other Parity Securities if Banco Santander does not have sufficient funds to make full payment to all of them. In such a situation, convertible capital securities of such series could lose all or part of their investment.

Furthermore, if the Trigger Event occurs but the relevant conversion of the convertible capital securities of any series into Common Shares is still to take place before the dissolution, liquidation or winding-up of Banco Santander, the entitlement of holders of convertible capital securities of any series will be to receive out of the relevant assets of Banco Santander a monetary amount equal to that which holders of convertible capital securities of such series would have received on any distribution of the assets of Banco Santander if the Trigger Conversion had taken place immediately prior to such dissolution, liquidation or winding-up.

Therefore, if the Trigger Event occurs, each holder of convertible capital securities of any series will be effectively further subordinated from being the holder of a subordinated debt instrument to being the holder of Common Shares and there is an enhanced risk that holders of convertible capital securities of such series will lose all or some of their investment.

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Holders of contingent convertible capital securities of any series will have limited rights after the Trigger Conversion and the issuance of the Common Shares to the Settlement Shares Depository (or to the relevant recipient in accordance with terms of the contingent convertible capital securities of the relevant series) will constitute an irrevocable and automatic release of all of Banco Santander’s obligations in respect of the contingent convertible capital securities of such series.

Following a Trigger Conversion, Banco Santander will be obligated to issue the Common Shares to the Settlement Shares Depository (or to the relevant recipient in accordance with the terms of the contingent convertible capital securities of the relevant series), which will hold the Common Shares on behalf of holders of contingent convertible capital securities of such series. Once the Common Shares are delivered to the Settlement Shares Depository (or to the relevant recipient in accordance with the terms of the contingent convertible capital securities of the relevant series), all of Banco Santander’s obligations under the contingent convertible capital securities of such series will be irrevocably and automatically released in consideration of such issuance to the Settlement Shares Depository (or to the relevant recipient in accordance with the terms of the contingent convertible capital securities of such series), and under no circumstances will such released obligations be reinstated and holders of contingent convertible capital securities of such series will not be entitled to any form of compensation in the event of Banco Santander’s potential recovery or change in Banco Santander’s CET1 ratio after the Conversion Settlement Date. With effect from the Conversion Settlement Date, holders of contingent convertible capital securities of any series will have recourse only to the Settlement Shares Depository for the delivery to them of Common Shares.

If Banco Santander does not deliver the Common Shares to the Settlement Shares Depository (or to the relevant recipient in accordance with the terms of the contingent convertible capital securities of the relevant series) following a Trigger Event, the only claim holders of contingent convertible capital securities of any series will have against Banco Santander will be for specific performance to have such Common Shares issued and delivered. Moreover, holders of contingent convertible capital securities of any series will not have any rights against Banco Santander with respect to repayment of the Liquidation Preference of the contingent convertible capital securities of any series or payment of Distributions or any other amount on, or in respect of, the contingent convertible capital securities of such series, in each case that is not due and payable, which liabilities will be automatically released. Accordingly, the Liquidation Preference of the contingent convertible capital securities will equal zero at all times from and after the Trigger Conversion and any Distributions will be cancelled or deemed to have been cancelled at all times thereafter and will not be due and payable, including any interest in respect of an interest period ending on any Distribution Payment Date falling between the date of a Trigger Event and the Trigger Conversion.

In addition, Banco Santander has not yet appointed a Settlement Shares Depository and may not be able to appoint a Settlement Shares Depository if a Trigger Conversion occurs. In such case, Banco Santander will effect, by means Banco Santander deems reasonable under the circumstances (including, without limitation, issuance of the Common Shares to another nominee or to holders of contingent convertible capital securities of any series directly) the issuance and/or delivery of the Common Shares, or, if holders of contingent convertible capital securities elect, ADSs, as applicable, to such holders. Such arrangements may be disadvantageous to, and more restrictive on, holders of contingent convertible capital securities of such series, such as involving a longer period of time before they receive ADSs or Common Shares than would be the case under the arrangements expected to be entered into with a Settlement Shares Depository or the inability to deliver ADSs. Nevertheless, such issuance also will irrevocably and automatically release all of Banco Santander’s obligations under the contingent convertible capital securities of such series as if the Common Shares had been issued to the Settlement Shares Depository.

The terms of the contingent convertible capital securities contain a waiver of set-off rights.

No holder of the contingent convertible capital securities may at any time exercise or claim any right, of or claim for, deduction, set-off, netting, compensation, retention or counterclaim arising directly or indirectly under

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or in connection with the contingent convertible capital securities against any right, claim or liability of Banco Santander or that Banco Santander may have or acquire against such holder, directly or indirectly and howsoever arising (and including all such rights, claims and liabilities arising under or in relation to any and all agreements or other instruments of any kind, whether or not relating to such contingent convertible capital securities).

The terms and conditions of the contingent convertible capital securities provide that holders shall be deemed to have waived all rights, of or claims for, deduction, set-off, netting, compensation, retention or counterclaim arising directly or indirectly under or in connection with the contingent convertible capital securities to the fullest extent permitted by applicable law in relation to all such actual and potential rights, claims and liabilities. As a result, holders will not at any time be entitled to set-off Banco Santander’s obligations under the contingent convertible capital securities against obligations owed by them to Banco Santander.

If a Delivery Notice is not duly delivered by a holder of contingent convertible capital securities of any series, that holder will bear the risk of fluctuations in the price of the Common Shares, and Banco Santander may, in its sole and absolute discretion, cause the sale of any Common Shares underlying the contingent convertible capital securities of such series.

In order to obtain delivery of the relevant Common Shares, or, if the holder elects, ADSs, upon conversion, the relevant holder must deliver a duly completed Delivery Notice in accordance with the provisions set out under “Description of Contingent Convertible Capital Securities—Settlement Procedures”. If a duly completed Delivery Notice is not so delivered, then such holder will bear the risk of fluctuations in the price of the Common Shares that may further affect the value to that holders of any Common Shares subsequently delivered. In addition, Banco Santander may, on the Notice Cut-off Date, in its sole and absolute discretion, elect to appoint a person (the “Selling Agent”) to (save as provided below) procure that all Common Shares held by the Settlement Shares Depository in respect of which no duly completed Delivery Notice has been delivered on or before the Notice Cut-off Date as aforesaid shall be sold by or on behalf of the Selling Agent as soon as reasonably practicable.

Due to the fact that, in the event of the Trigger Event, investors are likely to receive Common Shares at a time when the market price of the Common Shares may be low, the cash value of the Common Shares received upon any such sale could be substantially lower than the price paid for the contingent convertible capital securities of such series at the time of their purchase. In addition, the proceeds of such sale may be further reduced as a result of the number of Common Shares offered for sale at the same time being much greater than may be the case in the event of sales by individual holders of contingent convertible capital securities of any series.

Holders of contingent convertible capital securities of any series may be obliged to make a takeover bid in case of the Trigger Event if they take delivery of Common Shares.

Upon the occurrence of the Trigger Event, a holder of contingent convertible capital securities of any series receiving Common Shares may have to make a takeover bid addressed to the shareholders of Banco Santander pursuant to the consolidated text of the Securities Market Act approved by Royal Legislative Decree 4/2015 of 23 October, as amended, and Royal Decree 1066/2007 of 27 July 2007, as amended, on the legal regime of takeover bids, implementing Directive 2004/25/EC of the European Parliament and of the Council of 21 April 2004, if its aggregate holding in Banco Santander exceeds 30% of the available voting rights or if its aggregate holding in Banco Santander is less than 30% of such voting rights, but within 24 months of the date on which it acquired that lower percentage, it nominates a number of directors that, when taken together with any directors it has previously nominated, represent more than half of the members of Banco Santander’s management body, in each case as a result of the conversion of the contingent convertible capital securities of any series into Common Shares.

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Holders of contingent convertible capital securities of any series may be subject to disclosure obligations and/or may need approval by Banco Santander’s relevant Regulator and other authorities under certain circumstances.

As the contingent convertible capital securities of any series are convertible into Common Shares in certain circumstances, an investment in the contingent convertible capital securities of any series may result in holders of the contingent convertible capital securities of such series, upon conversion of the contingent convertible capital securities of such series into Common Shares, having to comply with certain approval and/or disclosure requirements pursuant to Spanish and other laws and regulations. Non-compliance with such approval and/or disclosure requirements may lead to the incurrence by holders of contingent convertible capital securities of such series of substantial fines and/or suspension of voting rights associated with the Common Shares. Accordingly, each potential investor should consult its legal advisers as to the terms of the contingent convertible capital securities of any series, in respect of its existing shareholding and the level of holding it would have if it receives Common Shares following a Trigger Event.

There is no restriction under the contingent convertible capital securities indenture on the amount or type of further securities or indebtedness which Banco Santander may incur.

Except as provided under “Description of Contingent Convertible Capital Securities—Subordination”, there is no restriction under the contingent convertible capital securities indenture on the amount or type of further securities or indebtedness which Banco Santander may issue or incur which ranks senior to, or pari passu with, the contingent convertible capital securities of any series. The incurrence of any such further indebtedness may reduce the amount recoverable by holders of contingent convertible capital securities of any series on a dissolution, liquidation or winding-up of Banco Santander in respect of the contingent convertible capital securities of such series and may limit the ability of Banco Santander to meet its obligations in respect of the contingent convertible capital securities of such series, and result in a holder of the contingent convertible capital securities of such series losing all or some of its investment in the contingent convertible capital securities of such series. In addition, the contingent convertible capital securities of any series do not contain any restriction on Banco Santander issuing securities that may have preferential rights to the Common Shares or securities ranking pari passu with the contingent convertible capital securities of such series and having similar or preferential terms to the contingent convertible capital securities of such series.

Prior to the issue and registration of the Common Shares to be delivered following the occurrence of the Trigger Event, holders of contingent convertible capital securities of any series will not be entitled to any rights with respect to such Common Shares, but will be subject to all changes made with respect to the Common Shares.

Any pecuniary rights with respect to the Common Shares, in particular the entitlement to dividends, shall only arise, and the exercise of voting rights and rights related thereto with respect to any Common Shares is only possible, after the date on which, following Trigger Conversion, as a matter of Spanish law the relevant Common Shares are issued and the person entitled to the Common Shares is registered as a shareholder in Iberclear and its participating entities in accordance with the provisions of, and subject to the limitations provided in, the articles of association of Banco Santander. Therefore, any failure by Banco Santander to issue, or effect the registration of, the Common Shares after the occurrence of the Trigger Event would result in the holders of contingent convertible capital securities of the relevant series not receiving any benefits related to the holding of the Common Shares and, on a dissolution, liquidation or winding-up of Banco Santander, the entitlement of any such holders will be an entitlement to receive out of the relevant assets of Banco Santander a monetary amount equal to that which holders of contingent convertible capital securities of such series would have received on any distribution of the assets of Banco Santander if such conversion had taken place immediately prior to such dissolution, liquidation or winding-up, as described in “Description of Contingent Convertible Capital Securities—Liquidation Distribution”.

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Furthermore, under Spanish law only the record holders of the Common Shares according to the registries kept by Iberclear and its participating entities are entitled to exercise voting, pre-emptive and other rights in respect of such Common Shares.

The contingent convertible capital securities of any series are Banco Santander’s exclusive obligations.

The contingent convertible capital securities of any series are Banco Santander’s exclusive obligations. Banco Santander is a holding company and conducts a substantial portion of its operations through its subsidiaries. Banco Santander’s subsidiaries are separate and distinct legal entities, and have no obligations to pay any amounts due on the contingent convertible capital securities of any series or to provide Banco Santander with funds to meet any of its payment obligations. Banco Santander’s rights to participate in the assets of any subsidiary if it is liquidated will be subject to the prior claims of the subsidiary’s creditors.

The contingent convertible capital securities of any series may not be a suitable investment for all investors.

The contingent convertible capital securities of any series are novel and complex financial instruments that involve a high degree of risk. As a result, an investment in the contingent convertible capital securities of any series and the Common Shares issuable following a Trigger Event will involve certain increased risks. Each potential investor in the contingent convertible capital securities of any series must determine the suitability of that investment in light of its own circumstances. In particular, each potential investor may wish to consider, either on its own or with the help of its financial and other professional advisers, whether it:

(i) has sufficient knowledge and experience to make a meaningful evaluation of the contingent convertible capital securities of such series, the merits and risks of investing in the contingent convertible capital securities of such series and the information contained or incorporated by reference in this prospectus, taking into account that the contingent convertible capital securities of such series may only be a suitable investment for professional or institutional investors;

(ii) has access to, and knowledge of, appropriate analytical tools to evaluate, in the context of its particular financial situation, an investment in the contingent convertible capital securities of such series and the impact the contingent convertible capital securities of such series will have on its overall investment portfolio;

(iii) has sufficient financial resources and liquidity to bear all of the risks of an investment in the contingent convertible capital securities of such series, including where the currency for payments in respect of the contingent convertible capital securities of such series is different from the potential investor’s currency and the possibility that the entire Liquidation Preference of the contingent convertible capital securities of any series could be lost, including following the exercise by the Relevant Resolution Authority of any Spanish Bail-in Power;

(iv) understands thoroughly the terms of the contingent convertible capital securities of such series, including the provisions relating to the payment and cancellation of Distributions and the Trigger Conversion of the contingent convertible capital securities of such series into Common Shares, and is familiar with the behavior of financial markets, including the possibility that the contingent convertible capital securities of any series may become subject to write down or conversion if the Spanish Bail-in Power is exercised; and

(v) is able to evaluate possible scenarios for economic, interest rate and other factors that may affect its investment and its ability to bear the applicable risks.

Sophisticated investors generally do not purchase complex financial instruments that bear a high degree of risk as stand-alone investments. They purchase such financial instruments as a way to enhance yield with an understood, measured, appropriate addition of risk to their overall portfolios. A potential investor should not invest in the contingent convertible capital securities of any series unless it has the knowledge and expertise

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(either alone or with a financial advisor) to evaluate how the contingent convertible capital securities of such series will perform under changing conditions, the resulting effects on the likelihood of the Trigger Conversion into Common Shares and the value of the contingent convertible capital securities of such series, and the impact this investment will have on the potential investor’s overall investment portfolio. Prior to making an investment decision, potential investors should consider carefully, in light of their own financial circumstances and investment objectives, all the information contained in this prospectus and the prospectus supplement or incorporated by reference herein.

The market value of the contingent convertible capital securities of any series may be influenced by unpredictable factors.

Certain factors, many of which are beyond Banco Santander’s control, will influence the value of the contingent convertible capital securities of any series and the price, if any, at which securities dealers may be willing to purchase or sell the contingent convertible capital securities of such series in the secondary market, including:

Accordingly, if holders sell their contingent convertible capital securities of any series in the secondary market, they may not be able to obtain a price equal to the Liquidation Preference of the contingent convertible capital securities of such series or a price equal to the price that they paid for the contingent convertible capital securities of such series.

The contingent convertible capital securities are not investment grade and are subject to the risks associated with non-investment grade securities.

The contingent convertible capital securities of any series, upon issuance, will not be considered to be investment grade securities, and as such will be subject to a higher risk of price volatility than higher-rated securities. Furthermore, deteriorating outlooks for Banco Santander or the Group, or volatile markets, could lead to a significant deterioration in market prices of below-investment grade rated securities such as the contingent convertible capital securities of any series.

Credit ratings may not reflect all risks associated with an investment in the contingent convertible capital securities of any series.

Ratings may not reflect the potential impact of all risks related to structure, market, additional factors discussed above, and other factors that may affect the value of the contingent convertible capital securities of any series.

Similar ratings assigned to different types of securities do not necessarily mean the same thing and any rating assigned to the contingent convertible capital securities of any series does not address the likelihood that Distributions or any other payments in respect of the contingent convertible capital securities of such series will be made on any particular date or at all. Credit ratings also do not address the marketability or market price of securities.

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Any change in the credit ratings assigned to the contingent convertible capital securities of any series may affect the market value of the contingent convertible capital securities of such series. Such change may, among other factors, be due to a change in the methodology applied by a rating agency to rating securities with similar structures to the contingent convertible capital securities of any series, as opposed to any revaluation of Banco Santander’s financial strength or other factors such as conditions affecting the financial services industry generally.

A credit rating is not a recommendation to buy, sell or hold securities and may be revised or withdrawn by the rating agency at any time. Potential investors should not rely on any rating of the contingent convertible capital securities of any series and should make their investment decision on the basis of considerations such as those outlined under “—The contingent convertible capital securities of any series may not be a suitable investment for all investors”.

In general, European regulated investors are restricted under the CRA Regulation from using credit ratings for regulatory purposes in the EEA, unless such ratings are issued by a credit rating agency established in the EU and registered under such regulation (and such registration has not been withdrawn or suspended), subject to transitional provisions that apply in certain circumstances whilst the registration application is pending. Such general restriction will also apply in the case of credit ratings issued by third-country non-EEA credit rating agencies, unless the relevant credit ratings are endorsed by an EEA-registered credit rating agency or the relevant third-country rating agency is certified in accordance with the CRA Regulation (and such endorsement action or certification, as the case may be, has not been withdrawn or suspended). Investors regulated in the United Kingdom are subject to similar restrictions under the UK CRA Regulation.

If the status of the rating agency rating the contingent convertible capital securities of any series changes for the purposes of the CRA Regulation or the UK CRA Regulation, relevant regulated investors may no longer be able to use the rating for regulatory purposes in the EEA or the United Kingdom, as applicable, and the contingent convertible capital securities of such series may have a different regulatory treatment. This may result in relevant regulated investors selling the contingent convertible capital securities of such series which may affect the trading prices of the contingent convertible capital securities of any series or the trading markets for such contingent convertible capital securities to the extent trading markets for such securities develop. Certain information with respect to the credit rating agencies and ratings will be disclosed in the relevant prospectus supplement.

Legal investment considerations may restrict certain investments.

The investment activities of certain investors may be subject to law or review or regulation by certain authorities. Each potential investor should determine for itself, on the basis of professional advice where appropriate, whether and to what extent (i) the contingent convertible capital securities of any series are lawful investments for it, (ii) the contingent convertible capital securities of such series can be used as collateral for various types of borrowing and (iii) other restrictions apply to its purchase or pledge of the contingent convertible capital securities of any series. Financial institutions should consult their legal advisers or the appropriate regulators to determine the appropriate treatment of the contingent convertible capital securities of any series under any applicable risk-based capital or similar rules.

The contingent convertible capital securities of any series may trade with accrued Distributions, but under certain circumstances described above, such Distributions may be cancelled and not paid on the relevant Distribution Payment Date.

The contingent convertible capital securities of any series may trade, and/or the prices for the contingent convertible capital securities of any series may appear in the relevant trading systems with accrued Distributions. If this occurs, purchasers of contingent convertible capital securities of any series in the secondary market will pay a price that reflects such accrued Distributions upon purchase of the contingent convertible capital securities

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of such series. However, if a payment of Distributions on any Distribution Payment Date is cancelled or deemed cancelled (either in whole or in part) as described herein and thus is not due and payable, purchasers of such contingent convertible capital securities of such series will not be entitled to that Distribution (or cancelled portion thereof) on the relevant Distribution Payment Date. This may affect the value of holders’ investment in the contingent convertible capital securities of any series.

Following a Trigger Conversion, the contingent convertible capital securities of any series will remain in existence until the applicable Conversion Settlement Date for the sole purpose of evidencing a holder’s rights to receive Common Shares or, if they elect, ADSs, as applicable, from the Settlement Shares Depository (or the relevant recipient in accordance with the terms of the contingent convertible capital securities of such series), and the rights of holders of contingent convertible capital securities of any series will be limited accordingly.

Following a Trigger Conversion, the contingent convertible capital securities of any series will remain in existence until the applicable Conversion Settlement Date (at which point the contingent convertible capital securities of any series will be cancelled) for the sole purpose of evidencing the right of holders of contingent convertible capital securities of any series to receive Common Shares, or, if they elect, ADSs, as applicable, from the Settlement Shares Depository (or the relevant recipient in accordance with the terms of the contingent convertible capital securities of such series). If Banco Santander has been unable to appoint a Settlement Shares Depository, Banco Santander will effect, by means Banco Santander deems reasonable under the circumstances (including, without limitation, issuance of the Common Shares to another nominee or to the holders of the contingent convertible capital securities of any series directly), the issuance and/or delivery of the Common Shares, or, if they elect, ADSs, as applicable, to them. See also “—Holders of contingent convertible capital securities of any series will have limited rights after the Trigger Conversion and the issuance of the Common Shares to the Settlement Shares Depository (or to the relevant recipient in accordance with terms of the contingent convertible capital securities of the relevant series) will constitute an irrevocable and automatic release of all of Banco Santander’s obligations in respect of the contingent convertible capital securities of such series”.

Although Banco Santander currently expects that beneficial interests in the contingent convertible capital securities of any series will be transferable between the Trigger Conversion and the Suspension Date and that any trades in the contingent convertible capital securities of any series would clear and settle through DTC in such period, there is no guarantee that this will be the case. Even if the contingent convertible capital securities of any series are transferable following the Trigger Conversion, there is no guarantee that an active trading market will exist for the contingent convertible capital securities of any series following the Trigger Conversion. Accordingly, the price received for the sale of any beneficial interest in any contingent convertible capital securities of any series during this period may not reflect the market price of such contingent convertible capital securities or the Common Shares. Furthermore, transfers of beneficial interests in the contingent convertible capital securities of any series may be restricted following the Trigger Conversion. For example, if the clearance and settlement of transactions in the contingent convertible capital securities of any series is suspended by DTC at an earlier time than currently expected, it may not be possible to transfer beneficial interests in the contingent convertible capital securities of such series in DTC and trading in the contingent convertible capital securities of such series may cease. The contingent convertible capital securities of any series may also cease to be admitted to the relevant stock exchange before or after the Suspension Date.

In addition, Banco Santander has been advised by DTC that it will suspend all clearance and settlement of transactions in the contingent convertible capital securities of any series on the Suspension Date. As a result, holders of contingent convertible capital securities of any series will not be able to settle the transfer of any contingent convertible capital securities of such series through DTC following the Suspension Date, and any sale or other transfer of the contingent convertible capital securities of any series that holders may have initiated prior to the Suspension Date that is scheduled to settle after the Suspension Date will be rejected by DTC and will not be settled through DTC.

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The contingent convertible capital securities of any series may cease to be admitted to trading on any stock exchange on which the contingent convertible capital securities of any series are then listed or admitted to trading after the Suspension Date.

Moreover, although holders of contingent convertible capital securities of any series will have a right to obtain their pro rata share of Common Shares upon the issuance of such Common Shares to the Settlement Shares Depository (or the relevant recipient in accordance with the terms of the contingent convertible capital securities of any series), the Common Shares will be registered in the name of the Settlement Shares Depository (or the relevant recipient in accordance with the terms of the contingent convertible capital securities of any series), and holders will not be able to sell or otherwise transfer any Common Shares until such time as they are delivered to them and registered in their name or to the account they specify.

Holders of contingent convertible capital securities of any series will be responsible for any taxes following a Trigger Conversion.

Neither Banco Santander nor any member of the Group will be liable for any taxes or duties (including, without limitation, any stamp duty, stamp duty reserve tax or any other capital, issue, transfer, registration, financial transaction or documentary tax or duty) arising on conversion or that may arise or be paid in connection with the issue and delivery of Common Shares following a Trigger Conversion. Holders of contingent convertible capital securities of any series must pay any taxes and duties (including, without limitation, any stamp duty, stamp duty reserve tax or any other capital, issue, transfer, registration, financial transaction or documentary tax or duty) arising on conversion in connection with the issue and delivery of Common Shares to the Settlement Shares Depository on their behalf.

Limitations on gross-up obligation under the contingent convertible capital securities of any series

Banco Santander’s obligation to pay additional amounts in respect of any withholding or deduction in respect of taxes under the terms of the contingent convertible capital securities of any series applies only to payments of distributions due and paid under the contingent convertible capital securities of any series and not to payments of Liquidation Preference. As such, Banco Santander would not be required to pay any additional amounts under the terms of the contingent convertible capital securities of any series to the extent any withholding or deduction applied to payments of Liquidation Preference. Accordingly, if any such withholding or deduction were to apply to any payments of Liquidation Preference under the contingent convertible capital securities of any series, holders of contingent convertible capital securities of such series may receive less than the full amount due under the contingent convertible capital securities of such series, and the market value of the contingent convertible capital securities of any series may be adversely affected. In any case, increased payments to comply with gross-up obligations will only be made if and to the extent that Banco Santander has sufficient Available Distributable Items. As such, Banco Santander would not be required to pay any additional amounts under the terms of the contingent convertible capital securities to the extent it had insufficient Available Distributable Items.

The contingent convertible capital securities of any series may be subject to substitution and/or variation without a holder’s consent

Subject as provided herein, in particular under “Description of Contingent Convertible Capital Securities—Substitution and Variation”, if a Capital Event or a Tax Event occurs, Banco Santander may, at its option, and without the consent or approval of the holders of the contingent convertible capital securities of such series, elect either (i) to substitute all (but not some only) of the contingent convertible capital securities of such series or (ii) to modify the terms of all (but not some only) of the contingent convertible capital securities of such series, in each case so that they are substituted for, or varied to, become, or remain, Qualifying Notes. While Qualifying Notes generally must contain terms that are materially no less favorable to holders of the contingent convertible capital securities of such series as the original terms of the contingent convertible capital securities of such series,

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there can be no assurance that the terms of any Qualifying Notes will be viewed by the market as equally favorable, or that the Qualifying Notes will trade at prices that are equal to the prices at which the contingent convertible capital securities of such series would have traded on the basis of their original terms.

Further, prior to the making of any such substitution or variation, Banco Santander, shall not be obliged to have regard to the tax position of individual holders of the contingent convertible capital securities of such series or to the tax consequences of any such substitution or variation for any such individual holder. No holder of the contingent convertible capital securities of such series shall be entitled to claim, whether from the Trustee, Banco Santander, or any other person, any indemnification or payment in respect of any tax consequence of any such substitution or variation upon an individual holder of the contingent convertible capital securities of such series.

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DESCRIPTION OF DEBT SECURITIES

The following is a summary of the general terms that will apply to any debt securities that may be offered by Banco Santander. The term “debt securities” does not include the “contingent convertible capital securities” described under “Description of Contingent Convertible Capital Securities”.

Each time that Banco Santander issues debt securities, Banco Santander will file a prospectus supplement and/or free writing prospectus with the SEC, which you should read carefully. The prospectus supplement and/or free writing prospectus will summarize specific financial terms of an investor’s security and may contain additional or different terms of those debt securities to those described in this prospectus. All references in this prospectus to a prospectus supplement in respect of any series of securities include references to a free writing prospectus if a free writing prospectus is filed to set forth any terms of such series. The terms presented here, together with the terms contained in the prospectus supplement, will be a description of the material terms of the debt securities, but if there is any inconsistency between the terms presented here and those in the prospectus supplement, those in the prospectus supplement will apply and will replace those presented here. Therefore, the statements made below in this section may not apply to each investor’s debt security. Investors should also read the indentures under which Banco Santander will issue the debt securities, which have been filed with the SEC as exhibits to the registration statement of which this prospectus is a part.

In this description of debt securities, the following expressions have the following meanings:

“Additional Tier 1 Capital” means additional tier 1 capital (capital de nivel 1 adicional) in accordance with Chapter 3 (Additional Tier 1 capital) of Title I (Elements of own funds) of Part Two (Own Funds and Eligible Liabilities) of the CRR and/or Applicable Banking Regulations at any time, including any applicable transitional, phasing in or similar provisions.

“Additional Tier 1 Instrument” means any instrument of Banco Santander qualifying as Additional Tier 1 Capital in whole or in part from time to time.

“Amounts Due” means the principal amount of, premium, if any, together with any accrued but unpaid interest, and Additional Amounts, if any, due on the debt securities of any series. References to such amounts will include amounts that have become due and payable, but which have not been paid, prior to the exercise of the Bail-in Power by the Relevant Resolution Authority.

“Applicable Banking Regulations” means at any time the laws, regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, then applicable to Banco Santander and/or the Group including, without limitation to the generality of the foregoing, the CRD IV, the BRRD, the SRM Regulation and those regulations, requirements, guidelines and policies relating to capital adequacy, resolution and/or solvency of the Regulator then applicable to Banco Santander and/or the Group including, among others, those giving effect to the MREL and the TLAC or any equivalent or successor principles, in each case to the extent then in effect in the Kingdom of Spain (whether or not such regulations, requirements, guidelines or policies have the force of law and whether or not they are applied generally or specifically to Banco Santander and/or the Group).

“Bail-in Power” means any power existing from time to time under, and exercised in compliance with, any laws, regulations, rules or requirements in effect in the Kingdom of Spain, relating to (i) the transposition of the BRRD, including its articles 48 and 59 (including but not limited to, Law 11/2015, RD 1012/2015 and any other implementing regulations), (ii) the SRM Regulation and (iii) the instruments, rules or standards created thereunder, pursuant to which any obligation of a Regulated Entity (or an affiliate of such Regulated Entity) can be reduced, cancelled, suspended, modified, or converted into shares, other securities, or other obligations of such Regulated Entity (or affiliate of such Regulated Entity).

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“BRRD” means Directive 2014/59/EU of 15 May establishing the framework for the recovery and resolution of credit institutions and investment firms or such other directive as may come into effect in place thereof, as amended from time to time.

“Business Day” means, unless otherwise provided for in the applicable prospectus supplement, any day, other than Saturday or Sunday, that is not a legal holiday nor a day on which banking institutions are authorized or required by law, regulation or executive order to close in the City of New York or London nor a day when the Trans-European Automated Real-time Gross Settlement Express Transfer system (the “TARGET2 System”), or any successor thereto, is closed for business.

“Calculation Agent” means the Trustee or such other person authorized by Banco Santander as the party responsible for calculating the rate(s) of interest and interest amount(s) and/or such other amount(s) from time to time in relation to any series of debt securities as may be specified in the relevant prospectus supplement.

“Capital Disqualification Event” means a change in Spanish law, Applicable Banking Regulations or any change in the application or official interpretation thereof that results or is likely to result in the entire outstanding aggregate principal amount of subordinated debt securities of any series ceasing to be included in, or counting towards, Banco Santander and/or the Group’s Tier 2 Capital.

“CET1 Capital” means at any time, the common equity tier 1 capital of Banco Santander or the Group, respectively, as calculated in accordance with Chapter 2 (Common Equity Tier 1 Capital) of Title I (Elements of own funds) of Part Two (Own Funds and Eligible Liabilities) of the CRR and/or Applicable Banking Regulations at such time, including any applicable transitional, phasing in or similar provisions;

“Common Equity Tier 1 Instruments” means instruments qualifying as CET1 Capital.

“CRD IV” means any or any combination of the CRD IV Directive, the CRR, and any CRD IV Implementing Measures.

“CRD IV Directive” means Directive 2013/36/EU of the European Parliament and of the Council of 26 June 2013 on access to the activity of credit institutions and the prudential supervision of credit institutions and investment firms, amending Directive 2002/87/EC and repealing Directives 2006/48/EC and 2006/49/EC or such other directive as may come into effect in place thereof, as amended or replaced from time to time.

“CRD IV Implementing Measures” means any regulatory capital rules implementing the CRD IV Directive or the CRR which may from time to time be introduced, including, but not limited to, delegated or implementing acts (regulatory technical standards) adopted by the European Commission, national laws and regulations, and regulations and guidelines issued by the Regulator, the European Banking Authority or any other relevant authority, which are applicable to Banco Santander (on a standalone basis) or the Group (on a consolidated basis) and which prescribe the requirements to be fulfilled by financial instruments for inclusion in the regulatory capital or the minimum requirement for own funds and eligible liabilities, as the case may be, of Banco Santander (on a standalone basis) or the Group (on a consolidated basis).

“CRR” means Regulation (EU) No. 575/2013 of the European Parliament and of the Council of 26 June 2013 on the prudential requirements for credit institutions and investment firms and amending Regulation (EU) No. 648/2012 or such other regulation as may come into effect in place thereof, as amended from time to time.

“Law 10/2014” means Law 10/2014 on the regulation, supervision and solvency of credit institutions (Ley 10/2014, de 26 de junio, de ordenación, supervisión y solvencia de entidades de crédito) as amended or replaced from time to time.

“Law 11/2015” means Law 11/2015 of 18 June, on recovery and resolution of credit institutions and investment firms (Ley 11/2015, de 18 de junio, de recuperación y resolución de entidades de crédito y empresas de servicios de inversión) as amended or replaced from time to time.

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“MREL” means the “minimum requirement for own funds and eligible liabilities” for credit institutions under the BRRD, set in accordance with Article 45 of the BRRD (as transposed in the Kingdom of Spain), Commission Delegated Regulation (EU) 2016/1450 of 23 May 2016, supplementing Directive 2014/59/EU of the European Parliament and of the Council with regard to regulatory technical standards specifying the criteria relating to the methodology for setting the minimum requirement for own funds and eligible liabilities and any other Applicable Banking Regulations.

“Principal Paying Agent” means any Person (which may include Banco Santander) authorized by Banco Santander to pay the principal of, or any premium or interest on, or any Additional Amounts with respect to, the debt securities of any series on behalf of Banco Santander. Unless otherwise specified in the applicable prospectus supplement, The Bank of New York Mellon, London Branch will act as the Principal Paying Agent in respect of the debt securities of any series.

“Person” means any individual, company, corporation, firm, partnership, joint venture, association, organization, state or agency of a state or other entity, whether or not having separate legal personality.

“Qualifying Notes” means, with respect to each applicable series of senior preferred debt securities, each series of senior non preferred debt securities and each series of subordinated debt securities, at any time, any securities issued directly by Banco Santander that have terms not otherwise materially less favorable to the holders of the senior preferred debt securities of such series, senior non preferred debt securities of such series or subordinated debt securities of such series than the terms of the senior preferred debt securities of such series, senior non preferred debt securities of such series or subordinated debt securities of such series, as applicable, provided that such securities shall:

(i) (a) in the case of applicable senior preferred debt securities and senior non preferred debt securities, contain terms which comply with the then current requirements for TLAC/MREL Eligible Instruments as embodied in the Applicable Banking Regulations, and (b) in the case of subordinated debt securities, contain terms which comply with the then current requirements for their inclusion in the Tier 2 Capital of Banco Santander; and

(ii) carry the same rate of interest as the senior preferred debt securities of such series, senior non preferred debt securities of such series or the subordinated debt securities of such series, as applicable, prior to the relevant substitution or variation pursuant to “—Substitution and Variation”; and

(iii) have the same denomination and aggregate outstanding principal amount as the senior preferred debt securities of such series, the senior non preferred debt securities of such series, or the subordinated debt securities of such series, as applicable, prior to the relevant substitution or variation pursuant to “—Substitution and Variation”; and

(iv) have the same date of maturity and the same dates for payment of interest as the senior preferred debt securities of such series, the senior non preferred debt securities of such series or the subordinated debt securities of such series, as applicable, prior to the relevant substitution or variation pursuant to “—Substitution and Variation”; and

(v) have at least the same ranking as the senior preferred debt securities of such series, the senior non preferred debt securities of such series, or the subordinated debt securities of such series, as applicable; and

(vi) not, immediately following such substitution or variation, (a) in the case of applicable senior preferred debt securities and senior non preferred debt securities, be subject to a TLAC/MREL Disqualification Event and/or a tax event that would entitle Banco Santander to redeem the debt securities as set forth under “—Redemption and Repurchase—Early Redemption for Taxation Reasons”; and (b) in the case of subordinated debt securities, be subject to a Capital Disqualification Event and/or a tax event that would entitle Banco Santander to redeem

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the debt securities as set forth under “—Redemption and Repurchase—Early Redemption for Taxation Reasons”; and

(vii) be listed or admitted to trading on any stock exchange as selected by Banco Santander, if the senior preferred debt securities of such series, the senior non preferred debt securities of such series, or the subordinated debt securities of such series, as applicable, were listed or admitted to trading on a stock exchange immediately prior to the relevant substitution or variation pursuant to “—Substitution and Variation.”

“RD 1012/2015” means Royal Decree 1012/2015, of 6 November developing Law 11/2015, as amended or superseded from time to time;

“Regulated Entity” means any entity to which BRRD, as implemented in the Kingdom of Spain (including but not limited to, Law 11/2015, RD 1012/2015 and any other implementing regulations), or any other Spanish law relating to the Bail-in Power, applies, which includes, certain credit institutions, investment firms, and certain of their parent or holding companies.

“Regulator” means the European Central Bank, the Bank of Spain, the Relevant Resolution Authority or such other or successor authority exercising primary bank supervisory authority or the role of primary bank resolution authority, in each case with respect to prudential or resolution matters in relation to Banco Santander and/or the Group.

“Relevant Resolution Authority” means the Spanish Fund for the Orderly Restructuring of Banks, the Bank of Spain, the European Single Resolution Board, as the case may be, according to Law 11/2015, and any other entity with the authority to exercise the Bail-in Power or any other resolution power from time to time.

“Spanish Insolvency Law” means the restated text of the Spanish Insolvency Law (Ley Concursal) approved by the Royal Decree-Legislative 1/2020, of 5 May, as amended from time to time.

“SRM Regulation” means Regulation (EU) No. 806/2014 of the European Parliament and of the Council of 15 July 2014, establishing uniform rules and a uniform procedure for the resolution of credit institutions and certain investment firms in the framework of a Single Resolution Mechanism and a Single Resolution Fund and amending Regulation (EU) No. 1093/2010, as amended or replaced from time to time.

“Supervisory Permission” means, in relation to any action, such supervisory permission (or, as appropriate, waiver) from the Regulator as is required therefor under Applicable Banking Regulations.

“Tier 2 Capital” means tier 2 capital (capital de nivel 2) in accordance with Chapter 4 (Tier 2 capital) of Title I (Elements of own funds) of Part Two (Own Funds and Eligible Liabilities) of the CRR and/or Applicable Banking Regulations at any time, including any applicable transitional, phasing in or similar provisions.

“Tier 2 Instrument” means any instrument of Banco Santander qualifying as Tier 2 Capital in whole or in part from time to time.

“TLAC” means the “total loss-absorbing capacity” requirement for global systemically important institutions under the CRR, set in accordance with Article 92a of the CRR and/or any other Applicable Banking Regulations.

A “TLAC/MREL Disqualification Event” shall have occurred at any time that all or part of the outstanding nominal amount of a series of senior non preferred debt securities or senior preferred debt securities (as applicable) does not fully qualify as TLAC/MREL Eligible Instruments of Banco Santander and/or the Group, except where such non-qualification (i) is due solely to the remaining maturity of the relevant securities (as applicable) being less than any period prescribed for TLAC/MREL Eligible Instruments by the Applicable

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Banking Regulations as at the issue date of the relevant securities or (ii) is as a result of the relevant securities (as applicable) being bought back by or on behalf of Banco Santander or a buy back of the relevant securities which is funded by or on behalf of Banco Santander.

“TLAC/MREL Eligible Instrument” means an instrument that is eligible to be counted towards the TLAC and/or MREL and, for the avoidance of doubt, irrespective of the quantum limitation that may be applicable to certain types of instruments by the Applicable Banking Regulations.

General

The debt securities are not deposits and are not insured or guaranteed by the U.S. Federal Deposit Insurance Corporation or any other government agency of the United States, Spain or any other jurisdiction.

The debt securities will be direct, unconditional and unsecured debt obligations of Banco Santander. The indentures do not limit the amount of debt securities that Banco Santander may issue. Banco Santander may issue debt securities in one or more series. The relevant prospectus supplement and any related issuer free writing prospectus for any particular series of debt securities will describe the terms of the offered debt securities, including but not limited to, some or all of the following terms:

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Holders of debt securities shall have no voting rights except those described under the heading “—Modification and Waiver” below.

Payments of Interest

Banco Santander will make any payments of interest and principal on any particular series of debt securities on the dates and, in the case of payments of interest, at the rate or rates, that Banco Santander sets out in, or that are determined by the method of calculation described in, the relevant prospectus supplement. All payments in respect of the debt securities will be subject in all cases to any fiscal or other laws and regulations applicable thereto in the place of payment (including FATCA, any regulations or agreements thereunder, any official interpretation thereof, any intergovernmental agreements with respect thereto, or any law implementing an intergovernmental agreement or any regulations or official interpretations relating thereto), subject to the provisions under “—Additional Amounts” below.

Status of the Debt Securities

Senior preferred debt securities

Unless the relevant prospectus supplement provides otherwise, the payment obligations of Banco Santander in respect of principal under the senior preferred debt securities of any series constitute direct, unconditional, unsubordinated and unsecured obligations (créditos ordinarios) of Banco Santander and, in accordance with Additional Provision 14.2 of Law 11/2015, but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, such payment obligations rank (i) pari passu among themselves and with any other Senior Higher Priority Liabilities (as defined below) and (ii) senior to (x) any Senior Non Preferred Liabilities (as defined below) and (y) any present and future subordinated obligations (créditos subordinados) of Banco Santander in accordance with Article 281 of the Spanish Insolvency Law.

Claims of holders of senior preferred debt securities in respect of interest accrued but unpaid as of the commencement of any insolvency procedure in respect of Banco Santander shall constitute subordinated claims (créditos subordinados) against Banco Santander ranking in accordance with the provisions of Article 281.1.3º of the Spanish Insolvency Law and no further interest shall accrue from the date of the declaration of insolvency of Banco Santander.

The obligations of Banco Santander under the senior preferred debt securities are subject to the Bail-in Power.

Senior Non Preferred Debt Securities

Unless the relevant prospectus supplement provides otherwise, the payment obligations of Banco Santander in respect of principal under the senior non preferred debt securities of any series constitute direct, unconditional,

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unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander and, in accordance with Additional Provision 14.2 of Law 11/2015, but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander, such payment obligations rank (i) pari passu among themselves and with any Senior Non Preferred Liabilities, (ii) junior to the Senior Higher Priority Liabilities (and, accordingly, upon the insolvency of Banco Santander, the payment obligations of Banco Santander in respect of principal under the senior non preferred debt securities will be met after payment in full of the Senior Higher Priority Liabilities) and (iii) senior to any present and future subordinated obligations (créditos subordinados) of Banco Santander in accordance with Article 281 of the Spanish Insolvency Law.

Claims of holders of senior non preferred debt securities in respect of interest accrued but unpaid as of the commencement of any insolvency procedure in respect of Banco Santander shall constitute subordinated claims (créditos subordinados) against Banco Santander ranking in accordance with the provisions of Article 281.1.3º of the Spanish Insolvency Law and no further interest shall accrue from the date of the declaration of insolvency of Banco Santander.

The obligations of Banco Santander under the senior non preferred debt securities are subject to the Bail-in Power.

“Senior Higher Priority Liabilities” means the unsubordinated and unsecured obligations (créditos ordinarios) of Banco Santander, other than the Senior Non Preferred Liabilities.

“Senior Non Preferred Liabilities” means any unsubordinated and unsecured senior non preferred obligations (créditos ordinarios no preferentes) of Banco Santander under Additional Provision 14.2 of Law 11/2015 (including any senior non preferred debt securities) and any other obligations which, by law and/or by their terms, and to the extent permitted by Spanish law, rank pari passu with the Senior Non Preferred Liabilities.

Subordinated Debt Securities

Unless the relevant prospectus supplement provides otherwise, the payment obligations of Banco Santander under the subordinated debt securities constitute direct, unconditional, unsecured and subordinated obligations (créditos subordinados) of Banco Santander according to Article 281.1 of the Spanish Insolvency Law and, in accordance with Additional Provision 14.3 of Law 11/2015, but subject to any other ranking that may apply as a result of any mandatory provision of law (or otherwise), upon the insolvency of Banco Santander rank for so long as the obligations of Banco Santander in respect of the subordinated debt securities constitute Tier 2 Instruments:

Banco Santander agrees with respect to any series of subordinated debt securities and each holder of subordinated debt securities of any series, by his or her acquisition of a subordinated debt security, will be

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deemed to have agreed to the above described subordination. Each such holder will be deemed to have irrevocably waived his or her rights of priority which would otherwise be accorded to him or her under the laws of Spain, to the extent necessary to effectuate the subordination provisions of the subordinated debt security. In addition, each holder of subordinated debt securities of any series by his or her acquisition of the securities authorizes and directs the Trustee on his or her behalf to take such action as may be necessary or appropriate to effectuate the subordination of the relevant subordinated debt securities as provided in the subordinated indenture and as summarized herein and appoints the Trustee his or her attorney-in-fact for any and all such purposes.

The obligations of Banco Santander under the subordinated debt securities are subject to the Bail-in Power.

Additional Amounts

Unless otherwise specified in the relevant prospectus supplement, all amounts payable (whether in respect of principal, redemption amount, interest or otherwise) in respect of any series of debt securities will be made free and clear of and without withholding or deduction for or on account of any present or future taxes, duties, assessments or governmental charges (collectively, the “Taxes”) of whatever nature imposed or levied by or on behalf of the Kingdom of Spain or any political subdivision thereof or any authority or agency therein or thereof having power to tax, unless the withholding or deduction of such Taxes, is required by law. In that event, Banco Santander shall pay such additional amounts (“Additional Amounts”) as will result in receipt by the holders of the debt securities of the particular series of such amounts as would have been received by them had no such withholding or deduction been required.

However, Banco Santander shall not be required to pay any Additional Amounts in respect of any debt securities:

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Additional Amounts will also not be paid with respect to any payment to a holder who is a fiduciary, a partnership, a limited liability company or person other than the sole beneficial owner of that payment, to the extent that payment would be required by the laws of Spain (or any political subdivision thereof) to be included in the income, for tax purposes, of a beneficiary or settlor with respect to the fiduciary, a member of that partnership, an interest holder in that limited liability company or a beneficial owner who would not have been entitled to the Additional Amounts had it been the holder.

For the purposes of (iv) above, the “Relevant Date” means, in respect of any payment, the date on which such payment first becomes due and payable, but if the full amount of the moneys payable has not been received by the Trustee on or prior to such due date, it means the first date on which, the full amount of such moneys having been so received and being available for payment to holders of debt securities, notice to that effect shall have been duly given to the holders of the relevant series of debt securities in accordance with the indenture.

Unless the context otherwise requires, any reference in this “Additional Amounts” section to “principal” shall include any premium payable, or Redemption Amount and any other amounts in the nature of principal payable pursuant to the relevant indenture and “interest” shall include all amounts payable described under “—Payments of Interest” above and any other amounts in the nature of interest payable under the relevant indenture.

As used in this “Additional Amounts” section, the term “Redemption Amount” means, as appropriate, the Maturity Redemption Amount, Early Redemption Amount (Tax), Early Redemption Amount (Capital Disqualification Event), Early Redemption Amount (Call), Early Redemption Amount (Put), Early Redemption Amount (Clean-up Call) and Early Termination Amount or such other amount in the nature of a redemption amount as may be specified in, or determined in accordance with the provisions of, the relevant prospectus supplement.

Except where the context requires otherwise, any reference in this prospectus and the relevant prospectus supplement to payment of principal of or interest on a debt security shall be deemed to include any Additional Amounts payable with respect thereto.

Additional Issuances

Banco Santander may, without the consent of the holders of the debt securities of any series, issue additional debt securities of such series having the same ranking and same interest rate, maturity date, redemption terms and other terms as the debt securities of such series described in the relevant prospectus supplement except for the price to the public, original interest accrual date, issue date and first interest payment date, provided however that such additional debt securities will not have the same CUSIP, ISIN or other identifying number as the outstanding debt securities of the relevant series unless the additional debt securities are fungible with the outstanding debt securities of the relevant series for U.S. federal income tax purposes. Any such additional debt

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securities, together with the debt securities of the relevant series offered by the relevant prospectus supplement, will constitute a single series of securities under the relevant indenture. There is no limitation on the amount of debt securities that Banco Santander may issue under the relevant indentures.

Redemption and Repurchase

Early Redemption for Taxation Reasons

Unless otherwise specified in the relevant prospectus supplement, the following shall apply if, in relation to the debt securities of any series, as a result of any change in, or amendment to, the laws or regulations of Spain or of any political subdivision thereof or any authority or agency therein or thereof having power to tax or in the interpretation or administration of any such laws or regulations which becomes effective on or after the date of issue of the first issued debt securities of such series or any earlier date specified in the relevant prospectus supplement, Banco Santander shall determine that (a) it would be required to pay additional amounts as described in “—Additional Amounts” above or (b) it would not be entitled to claim a deduction in computing tax liabilities in Spain in respect of any interest to be paid on the next interest payment date on such series of debt securities or the value of such deduction to Banco Santander would be materially reduced or (c) the applicable tax treatment of the debt securities of such series changes in a material way that was not reasonably foreseeable at the issue date. In any such case Banco Santander may, at its option and having given no less than five (5) nor more than 30 days’ notice (or such lesser period as may be specified in the relevant prospectus supplement) (ending, in the case of debt securities which bear interest at a floating rate, on a day upon which interest is payable) to the holders of the debt securities of such series in accordance with the terms described under “—Notices” below (which notice shall be irrevocable) and a concurrent copy thereof to the Trustee, redeem in whole, but not in part, the relevant debt securities in accordance with the requirements of Applicable Banking Regulations in force at the relevant time, at their early tax redemption amount (the “Early Redemption Amount (Tax)”) (which shall be their principal amount or at such other Early Redemption Amount (Tax) as may be specified in or determined as described in the relevant prospectus supplement), together with accrued interest (if any) thereon to (but excluding) the date fixed for redemption; provided, however, that (i) in the case of (a) above, no such notice of redemption may be given earlier than 90 days (or, in the case of debt securities which bear interest at a floating rate a number of days which is equal to the aggregate of the number of days falling within the then current interest period applicable to the debt securities of such series plus 60 days) prior to the earliest date on which Banco Santander would be obliged to pay such additional amounts were a payment in respect of the debt securities of such series then due and (ii) in the case of senior non preferred debt securities, subordinated debt securities or senior preferred debt securities where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement only, redemption for taxation reasons may only take place in accordance with Applicable Banking Regulations in force at the relevant time and subject to Banco Santander obtaining, with respect to the subordinated debt securities, the senior non preferred debt securities or, if applicable, the senior preferred debt securities of such series, the prior Supervisory Permission therefor, if and as required.

Early Redemption of Senior Debt Securities for a TLAC/MREL Disqualification Event

Unless otherwise specified in the relevant prospectus supplement, if, in relation to senior non preferred debt securities of any series or senior preferred debt securities where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement only, a TLAC/MREL Disqualification Event has occurred and is continuing, then Banco Santander may, at its option and having given not less than five (5) nor more than 30 days’ notice (or such lesser period as may be specified in the relevant prospectus supplement) (ending, in the case of the relevant securities which bear interest at a floating rate, on a day upon which interest is payable) to the holders of the relevant securities in accordance with the terms described under “—Notices” below (which notice shall be irrevocable and shall specify the date for redemption) and a concurrent copy thereof to the Trustee, elect to redeem in whole but not in part the outstanding securities of such series at their principal amount, together with any accrued and unpaid interest thereon to (but excluding) the date fixed for redemption (the “Early Redemption Amount (TLAC/MREL Disqualification Event)”).

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Redemption on the basis of a TLAC/MREL Disqualification Event is subject to Banco Santander obtaining prior Supervisory Permission if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time.

Early Redemption of Subordinated Debt Securities for a Capital Disqualification Event

Unless otherwise specified in the relevant prospectus supplement, if, in relation to subordinated debt securities of any series, there is a Capital Disqualification Event, Banco Santander may, at its option and having given no less than five (5) nor more than 30 days’ notice (or such lesser period as may be specified in the relevant prospectus supplement) (ending, in the case of subordinated debt securities which bear interest at a floating rate, on a day upon which interest is payable) to the holders of the subordinated debt securities of such series in accordance with the terms described under “—Notices” below (which notice shall be irrevocable) and a concurrent copy thereof to the Trustee, redeem in whole but not in part the outstanding subordinated debt securities of such series in accordance with the requirements of Applicable Banking Regulations in force at the relevant time) at their early capital disqualification event redemption amount (the “Early Redemption Amount (Capital Disqualification Event)”) (which shall be their principal amount or such other Early Redemption Amount (Capital Disqualification Event) as may be specified in or determined in the relevant prospectus supplement), together with any accrued and unpaid interest thereon to (but excluding) the date fixed for redemption; provided, however, that the Regulator consents to redemption of the subordinated debt securities of such series.

Redemption for a Capital Disqualification Event is subject to the prior consent of the Regulator if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time.

Early redemption at the option of Banco Santander (Clean-up Redemption)

If the relevant prospectus supplement specifies that the clean-up redemption option is applicable in respect of any series and if 75% or any higher percentage specified in the relevant prospectus supplement (the “Clean-up Percentage”) of the initial aggregate nominal amount of such series (which, for the avoidance of doubt, includes any additional issuances issued subsequently and constituting a single series of securities under the relevant indenture) have been redeemed or purchased by, or on behalf of, Banco Santander, Banco Santander may, on any date that is an interest payment date, as its option and having given not less than five (5) nor more than 30 days’ notice (or such lesser period as may be specified in the relevant prospectus supplement) (ending, in the case of the relevant securities which bear interest at a floating rate, on a day upon which interest is payable) to the holders of the relevant securities in accordance with the terms described under “—Notices” below (which notice shall be irrevocable and shall specify the date for redemption) and a concurrent copy thereof to the Trustee, elect to redeem in whole but not in part the outstanding securities of such series.

The securities of the relevant series will be redeemed at their early redemption amount (the “Early Redemption Amount (Clean-up Call)”) (which shall be their principal amount or such other amount as may be specified in, or determined in accordance with, the relevant prospectus supplement), together with any accrued and unpaid interest thereon to (but excluding) the date fixed for redemption.

The Clean-up Redemption is subject to Banco Santander obtaining prior Supervisory Permission if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time. Clean-up Redemption of subordinated debt securities may be made only after five years from their date of issuance or any other minimum period permitted by the Applicable Banking Regulations.

Optional Early Redemption (Call)

Unless otherwise specified in the relevant prospectus supplement, Banco Santander may, upon the expiration of the appropriate notice (described below) and subject to such conditions as may be specified in the

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relevant prospectus supplement, redeem in whole (but not, unless and to the extent that the relevant prospectus supplement specifies otherwise, in part) the debt securities of such series at their call early redemption amount (the “Early Redemption Amount (Call)”) (which shall be their principal amount or such other Early Redemption Amount (Call) as may be specified in or determined in the relevant prospectus supplement), together with any accrued interest (if any) thereon to (but excluding) the date or dates fixed for redemption.

In the case of senior non preferred debt securities, subordinated debt securities or senior preferred debt securities constituting TLAC/MREL Eligible Instruments, redemption at the option of Banco Santander will be subject to the prior consent of the Regulator if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time. In particular, Optional Early Redemption (Call) of subordinated debt securities may be made only after five years from their date of issuance or any other minimum period permitted by the Applicable Banking Regulations.

Partial Redemption

If the debt securities of any series are to be redeemed in part only on any date in accordance with “—Optional Early Redemption (Call)” above, the debt securities to be redeemed will be selected not more than 30 days nor less than five (5) days prior to such redemption date by the Trustee pro rata to their principal amounts, or by lot or by such method as the Trustee deems fair and appropriate, provided that the amount redeemed in respect of the debt securities of such series shall be equal to the minimum authorized denomination or an integral multiple thereof, subject always to compliance with all applicable laws and the requirements of any clearing system on which the debt securities of such series may be cleared and of any listing authority, stock exchange and/or quotation system on which the debt securities of such series may be listed and/or quoted. In the case of debt securities issued in global form, DTC shall select Book-Entry Interests in such debt securities as described under “—Form of Securities; Book-Entry System” below. The Trustee shall not be liable for selections made by it in accordance with this paragraph or for selections made by DTC. No debt securities of $2,000 or less can be redeemed in part.

In the case of senior non preferred debt securities and subordinated debt securities partial redemption will be subject to the prior consent of the Regulator if and as required under Applicable Banking Regulations and may only take place in accordance with Applicable Banking Regulations in force at the relevant time.

Optional Early Redemption (Put) of Senior Preferred Debt Securities

Unless otherwise specified in the relevant prospectus supplement, Banco Santander shall, upon the exercise of the relevant option by a holder of senior preferred debt securities of any series, redeem the senior preferred debt securities of such series on the date or the dates specified in the relevant prospectus supplement at the put early redemption amount (the “Early Redemption Amount (Put)”) (which shall be the principal amount or such other Early Redemption Amount (Put) as may be specified in or determined in the relevant prospectus supplement), together with accrued interest (if any) thereon. In order to exercise such option, the holder of the senior preferred debt securities of such series must, not less than 60 days before the date so specified (or such other period as may be specified in the relevant prospectus supplement), deposit a duly completed redemption notice in the form which is available from the specified office of the Trustee specifying the aggregate principal amount in respect of which such option is exercised (which must be the minimum denomination specified in the relevant prospectus supplement or an integral multiple thereof). Such notice must also be delivered in accordance with the requirements of the applicable clearing system. No option exercised may be withdrawn (except as provided in the relevant indenture).

The Early Redemption (Put) shall not apply in the case of senior non preferred debt securities or subordinated debt securities of any series and holders of senior non preferred debt securities or subordinated debt securities of any series may not redeem the senior non preferred debt securities or subordinated debt securities of such series prior to the maturity date of such series.

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A holder of any series of senior preferred debt securities may not exercise such option in respect of any series of senior preferred debt securities which is the subject of an exercise by Banco Santander of its option to redeem such series of senior preferred debt securities under “—Early Redemption for Taxation Reasons” or “—Optional Early Redemption (Call)” above.

Notice of Redemption

For purposes of this section “—Redemption and Repurchase”, the appropriate notice to be given by Banco Santander to the Trustee and the holders of the debt securities of such series, shall be signed by two duly authorized officers of Banco Santander and shall specify:

Any such notice shall be irrevocable, and the delivery thereof shall oblige Banco Santander to make the redemption therein specified (unless the Bail-in Power is exercised by the Relevant Resolution Authority before the occurrence of such redemption).

Repurchase of Debt Securities

Banco Santander and any of its subsidiaries or any third party designated by any of them, may at any time repurchase debt securities in the open market or otherwise and at any price.

In the case of subordinated debt securities, senior non preferred debt securities and senior preferred securities where the TLAC/MREL Disqualification Event has been specified of any series, the repurchase of the relevant securities of such series by Banco Santander or any of its subsidiaries shall take place in accordance with Applicable Banking Regulations in force at the relevant time, including the applicable limits referred to in CRR, and will be subject to the prior consent of the Regulator, if and as required.

Modification and Waiver

Modification

Banco Santander and the Trustee may make certain modifications and amendments of the applicable indenture with respect to any series of debt securities without the consent of the holders of the debt securities of that series, including for, but not limited to, any of the following purposes:

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In addition to the permitted amendments described in the preceding paragraph, Banco Santander and the Trustee may amend or supplement the relevant indenture or the debt securities of any series and the related supplemental indenture without the consent of any holders of the debt securities of such series to conform the provisions of the relevant indenture to this “Description of Debt Securities” section in this registration statement and the applicable prospectus supplement.

Banco Santander may make other modifications and amendments with the consent of the holder or holders of not less than a majority in aggregate outstanding principal amount of the debt securities of the series outstanding under the indenture that are affected by the modification or amendment, voting as one class. However, Banco Santander may not make any modification or amendment without the consent of the holder of each debt security affected that would:

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In addition, material variations in the terms and conditions of debt securities of any series, including modifications relating to subordination, redemption, an Senior Preferred Debt Security Event of Default, a Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, (as those terms are defined under “—Events of Default and Defaults; Limitations of Remedies” below), may require the non-objection from, or consent of, the Regulator or its successor.

Events of Default and Defaults; Limitation of Remedies

Senior Preferred Debt Security Event of Default

Unless the relevant prospectus supplement provides otherwise, a “Senior Preferred Debt Security Event of Default” with respect to any series of senior preferred debt securities shall result if:

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Under the terms of the senior preferred debt securities indenture, no exercise of a resolution tool or resolution power by the Relevant Resolution Authority or any action in compliance therewith shall constitute a Senior Preferred Debt Security Event of Default.

If any Senior Preferred Debt Security Event of Default shall occur in relation to any series of senior preferred debt securities, the Trustee or the holders of at least 25% in outstanding principal amount of the senior preferred debt securities of that series may at their discretion declare that the senior preferred debt securities of such series and all interest then accrued thereon shall be forthwith due and payable, whereupon the same shall become immediately due and payable at its early termination amount (the “Early Termination Amount”) (which shall be its principal amount or such other Early Termination Amount as may be specified in or determined in accordance with the relevant prospectus supplement, together with all interest (if any) accrued thereon), without presentment, demand, protest or other notice of any kind, all of which Banco Santander will expressly waive, anything contained in the senior preferred debt securities of such series to the contrary notwithstanding, unless, prior thereto, all Senior Preferred Debt Security Events of Default in respect of the senior preferred debt securities of such series shall have been cured.

Notwithstanding the preceding paragraph, under Spanish law, interest on debt instruments accruing after commencement of insolvency proceedings against the issuer may not be declared as due and payable after the commencement of insolvency proceedings against the issuer.

Notwithstanding any contrary provisions, nothing shall impair the right of a holder, absent the holder’s consent, to sue for any payments due but unpaid with respect to the senior preferred debt securities.

Senior Non Preferred Debt Security Event of Default

Unless the relevant prospectus supplement provides otherwise, subject to the conditions described below, if any of the following events occurs and is continuing with respect to the senior non preferred debt securities of any series it shall constitute a “Senior Non Preferred Debt Security Event of Default”:

Under the terms of the senior non preferred debt securities indenture, no exercise of a resolution tool or resolution power by the Relevant Resolution Authority or any action in compliance therewith shall constitute a Senior Non Preferred Debt Security Event of Default.

If a Senior Non Preferred Debt Security Event of Default occurs as set forth in paragraph (i) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the senior non preferred debt securities of that series may institute proceedings for the winding up or liquidation of Banco Santander but may take no further action in respect of such default.

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If a Senior Non Preferred Debt Security Event of Default occurs as set forth in paragraph (ii) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the senior non preferred debt securities of that series may declare the senior non preferred debt securities of such series immediately due and payable whereupon the senior non preferred debt securities of such series shall, when permitted by applicable Spanish Insolvency Law, become immediately due and payable at their Early Termination Amount together with all interest (if any) accrued thereon.

Without prejudice to paragraphs (i) and (ii) above, the Trustee or the holders of at least 25% in outstanding principal amount of the senior non preferred debt securities of any series may at their discretion and without further notice, institute such proceedings against Banco Santander as they may think fit to enforce any obligation, condition or provision binding on Banco Santander under the senior non preferred debt securities of such series, provided that, except as provided in paragraph (ii) winding up above, Banco Santander shall not as a consequence of such proceedings be obliged to pay any sum or sums representing or measured by reference to principal or interest in respect of the senior non preferred debt securities of such series sooner than the same would otherwise have been payable by it or any damages.

Notwithstanding any contrary provisions, nothing shall impair the right of a holder, absent the holder’s consent, to sue for any payments due but unpaid with respect to the senior non preferred debt securities of any series.

Subordinated Debt Security Event of Default

Unless the relevant prospectus supplement provides otherwise, subject to the conditions described below, if any of the following events occurs and is continuing with respect to the subordinated debt securities of any series it shall constitute a “Subordinated Debt Security Event of Default”:

Under the terms of the subordinated debt securities indenture, no exercise of a resolution tool or resolution power by the Relevant Resolution Authority or any action in compliance therewith shall constitute a Subordinated Debt Security Event of Default.

If a Subordinated Debt Security Event of Default occurs as set forth in paragraph (i) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the subordinated debt securities of that series may institute proceedings for the winding up or liquidation of Banco Santander but may take no further action in respect of such default.

If a Subordinated Debt Security Event of Default occurs as set forth in paragraph (ii) above, then the Trustee or the holders of at least 25% in outstanding principal amount of the subordinated debt securities of that series may declare the subordinated debt securities of such series immediately due and payable whereupon the subordinated debt securities of such series shall, when permitted by applicable Spanish Insolvency Law, become immediately due and payable at their Early Termination Amount together with all interest (if any) accrued thereon.

Without prejudice to paragraphs (i) and (ii) above, the Trustee or the holders of at least 25% in outstanding principal amount of the subordinated debt securities of any series may at their discretion and without further

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notice, institute such proceedings against Banco Santander as they may think fit to enforce any obligation, condition or provision binding on Banco Santander under the subordinated debt securities of such series, provided that, except as provided in paragraph (ii) winding up above, Banco Santander shall not as a consequence of such proceedings be obliged to pay any sum or sums representing or measured by reference to principal or interest in respect of the subordinated debt securities of such series sooner than the same would otherwise have been payable by it or any damages.

Notwithstanding any contrary provisions, nothing shall impair the right of a holder, absent the holder’s consent, to sue for any payments due but unpaid with respect to the subordinated debt securities of any series.

Events of Default and Defaults—General

The Trustee may without prejudice to its rights in respect of any subsequent Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default from time to time and at any time waive any Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default or authorize any proposed Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default by Banco Santander, provided that in its opinion the interests of the holders shall not be materially prejudiced thereby and, provided, further, that the Trustee shall not exercise any powers conferred on it by this clause in contravention of any notice in writing to the Trustee made pursuant to the terms described under “—Limitations on Suits” above but no such notice shall affect any waiver or authorization previously given or made.

The holder or holders of not less than a majority in aggregate principal amount of the outstanding debt securities of any series may waive any past Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, except an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default in respect of the payment of interest, if any, or principal of (or premium, if any) or payments on, any debt security or a covenant or provision of the applicable indenture which cannot be modified or amended without the consent of each holder of debt securities of such series.

Subject to the provisions of the applicable indenture relating to the duties of the Trustee, if an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default occurs and is continuing with respect to the debt securities of any series, the Trustee will be under no obligation to any holder or holders of the debt securities of the series, unless they have offered indemnity satisfactory to the Trustee in its sole discretion. Subject to the indenture provisions for the indemnification of the Trustee, the holder or holders of a majority in aggregate principal amount of the outstanding debt securities of any series shall have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the series, if the direction is not in conflict with any rule of law or with the applicable indenture and the Trustee does not determine that the action would be unjustly prejudicial to the holder or holders of any debt securities of any series not taking part in that direction. The Trustee may take any other action that it deems proper which is not inconsistent with that direction.

The indentures provide that the Trustee will, within 90 days after the occurrence of an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default with respect to the debt securities of any series, give to each holder of the debt securities of such series notice of the Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default of which the Trustee has received written notice, unless the Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default has been cured or waived. However, the Trustee shall be protected in withholding notice if it determines in good faith that withholding notice is in the interest of the holders.

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Neither a cancellation of debt securities of any series, a reduction, in part or in full, of the principal amount of debt securities of any series or any accrued and unpaid interest on such debt securities, the conversion thereof into another security or obligation of Banco Santander or another person, in each case, as a result of the exercise of the Bail-in Power by the Relevant Resolution Authority with respect to Banco Santander, nor the exercise of any Bail-in Power by the Relevant Resolution Authority with respect to such debt securities, will be an event of default or otherwise constitute non-performance of a contractual obligation, or entitle the holders of such securities to any remedies, which are hereby expressly waived.

Substitution of Issuer

Banco Santander may, without the consent of the holders of any of the debt securities of any series, consolidate or amalgamate with, merge into any other corporation or convey or transfer or lease Banco Santander’s properties and assets substantially as an entirety to any person, provided that (a) any successor corporation formed by any such consolidation, amalgamation or merger, or any transferee or lessee of such assets, is a company organized under the laws of any part of the European Union that assumes, by a supplemental indenture, Banco Santander’s obligations on the debt securities of such series and under the applicable indenture, and such supplemental indenture is executed by Banco Santander and such successor entity, if applicable, and delivered to the Trustee, in form satisfactory to the Trustee; (b) immediately after giving effect to such consolidation, amalgamation, merger, conveyance or transfer, no Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable and no event which, after notice or lapse of time or both, would become an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable, shall have occurred and be continuing; and (c) Banco Santander shall have delivered to the Trustee an officer’s certificate and an opinion of counsel stating that such consolidation, amalgamation, merger, conveyance or transfer and such supplemental indenture, as the case may be, comply with the indenture and all conditions precedent have been complied with.

Any direct or indirect subsidiary of Banco Santander may assume the obligations of Banco Santander under any series of debt securities, subject to the prior consent of the Regulator, if required, with respect to any series of subordinated debt securities or debt securities, without the consent of the holders of any series of debt securities, provided that (a) the successor entity shall expressly assume such obligations by an amendment to the relevant indenture, executed by Banco Santander and such successor entity, if applicable, and delivered to the Trustee, in form satisfactory to the Trustee, and Banco Santander shall, by amendment to the relevant indenture, unconditionally guarantee all of the obligations of such successor entity under the debt securities of such series and the relevant indenture as so modified by such amendment; (b) immediately after giving effect to such assumption of obligations, no Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable, and no event which, after notice or lapse of time or both, would become an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable, shall have occurred and be continuing; and (c) Banco Santander shall have delivered to the Trustee an officer’s certificate and an opinion of counsel in such forms as are required in the relevant indenture.

In the event of any assumption, Additional Amounts under the debt securities of any series will be payable for taxes imposed by the jurisdiction of incorporation or tax residence of the assuming entity (subject to exceptions equivalent to those that apply to the obligation to pay Additional Amounts for taxes imposed by the laws of Spain) rather than taxes imposed by Spain. Additional Amounts for payments of interest or principal due prior to the date of the assumption will be payable only for taxes imposed by Spain. The assuming corporation will also be entitled to redeem the debt securities of any series in the circumstances described above under the section “—Early Redemption for Taxation Reasons” for any change or amendment to, or change in the application or official interpretation of, the laws or regulations of the assuming entity’s jurisdiction of incorporation or tax residence, which change or amendment must, in the case of a substituted issuer, occur subsequent to the date of such assumption if the assuming entity is not incorporated or tax resident in Spain.

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Upon such assumption, Banco Santander will be released from all its obligations under the applicable debt securities and indentures other than in respect of the guarantee described above.

An assumption of the obligations of Banco Santander under any series of debt securities might be deemed for U.S. federal income tax purposes to be an exchange by the beneficial owners of the debt securities of such series for new debt securities, which could result in recognition of taxable gain or loss for these purposes and possible other adverse tax consequences for such beneficial owners that are U.S. taxpayers. U.S. beneficial owners should consult their tax advisors regarding the U.S. federal, state and local income tax consequences of an assumption.

Waiver of Right of Set-off

Subject to applicable law, neither any holder or beneficial owner of the senior preferred debt securities where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement, senior non preferred debt securities of any series, the subordinated debt securities of any series nor the Trustee acting on behalf of the holders of the senior preferred debt securities of such series, the senior non preferred debt securities of such series or the subordinated debt securities of such series, may exercise, claim or plead any right of set-off, compensation or retention in respect of any amount owed to it by Banco Santander in respect of, or arising under, or in connection with, the senior preferred debt securities of such series or the senior preferred debt securities indenture, the senior non preferred debt securities of such series or the senior non preferred debt securities indenture or the subordinated debt securities of such series or the subordinated debt securities indenture, as applicable, and each holder and beneficial owner of the senior preferred debt securities of such series, the senior non preferred debt securities of such series and the subordinated debt securities of such series, by virtue of its holding of the senior preferred debt securities of such series or any interest therein, any senior non preferred debt securities of such series or any interest therein or any subordinated debt securities of such series or any interest therein, as applicable, and the Trustee acting on behalf of such holders, shall be deemed to have waived all such rights of set-off, compensation or retention. If, notwithstanding the above, any amounts due and payable to any holder or beneficial owner of a senior preferred debt security where the TLAC/MREL Disqualification Event has been specified as applicable in the relevant prospectus supplement or any interest therein, a senior non preferred debt security of any series or any interest therein or to any holder or beneficial owner of a subordinated debt security of any series or any interest therein by Banco Santander in respect of, or arising under, the senior preferred debt securities of such series, the senior non preferred debt securities of such series or the subordinated debt securities of such series are discharged by set-off, such holder or beneficial owner shall, subject to applicable law, immediately pay an amount equal to the amount of such discharge to Banco Santander (or, if the event of any voluntary or involuntary liquidation of Banco Santander shall have occurred, the liquidator or administrator of Banco Santander, as the case may be) and, until such time as payment is made, shall hold an amount equal to such amount in trust (where possible) or otherwise for Banco Santander (or the liquidator or administrator of Banco Santander, as the case may be) and, accordingly, any such discharge shall be deemed not to have taken place.

Substitution and Variation

With respect to senior non preferred debt securities of any series and any applicable series of senior preferred debt securities, if a TLAC/MREL Disqualification Event or a tax event that would entitle Banco Santander to redeem the debt securities of such series as set forth under “—Redemption and Repurchase—Early Redemption for Taxation Reasons” occurs and is continuing, Banco Santander may substitute all (but not some) of the debt securities of such series or modify the terms of all (but not some) of the debt securities of such series, without any requirement for the consent or approval of the holders of the debt securities of such series, so that they are substituted for, or varied to, become, or remain, Qualifying Notes, subject to having given not less than five (5) nor more than 30 days’ notice to the holders of the debt securities of such series in accordance with the terms described under “—Notices” and to the Trustee (which notice shall be irrevocable and shall specify the date for substitution or, as applicable, variation), and subject to obtaining Supervisory Permission therefor, if and as required under Applicable Banking Regulations.

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With respect to subordinated debt securities of any series, if a Capital Disqualification Event or a tax event that would entitle Banco Santander to redeem the debt securities as set forth under “—Redemption and Repurchase—Early Redemption for Taxation Reasons” occurs and is continuing, Banco Santander may substitute all (but not some) of the subordinated debt securities of any series or modify the terms of all (but not some) of the subordinated debt securities of such series, without any requirement for the consent or approval of the holders of the subordinated debt securities of such series, so that they are substituted for, or varied to, become, or remain, Qualifying Notes, subject to having given not less than five (5) nor more than 30 days’ notice to the holders of the subordinated debt securities of such series in accordance with the terms described under “—Notices” and to the Trustee (which notice shall be irrevocable and shall specify the date for substitution or, as applicable, variation), and subject to obtaining Supervisory Permission therefor, if and as required under Applicable Banking Regulations.

Any such notice shall specify the relevant details of the manner in which such substitution or variation shall take effect and where the holders of the senior preferred debt securities of such applicable series, senior non preferred debt securities of such series or subordinated debt securities of such series, as applicable, can inspect or obtain copies of the new terms and conditions of the senior preferred debt securities of such applicable series, senior non preferred debt securities of such series or subordinated debt securities of such series, as applicable. Such substitution or variation will be effected without any cost or charge to such holders.

The senior preferred debt securities of any applicable series, senior non preferred debt securities of any series and subordinated debt securities of any series, as applicable, shall cease to bear interest from (and including) the date of substitution thereof.

Any holder or beneficial owner of the senior preferred debt securities of any applicable series, senior non preferred debt securities of any series or subordinated debt securities of any series, as applicable, shall, by virtue of its acquisition of the senior preferred debt securities of any applicable series, senior non preferred debt securities of any series or any beneficial interest therein or the subordinated debt securities of any series or any beneficial interest therein, as applicable, be deemed to accept the substitution or variation of the terms of the senior preferred debt securities of such series, senior non preferred debt securities of such series or subordinated debt security of such series, as applicable, and to grant to Banco Santander full power and authority to take any action and/or to execute and deliver any document in the name and/or on behalf of such holder which is necessary or convenient to complete the substitution or variation of the terms of the senior preferred debt securities of such series, senior non preferred debt securities of such series or subordinated debt securities of such series, as applicable.

A substitution or a modification of the terms of the senior preferred debt securities of any series, the senior non preferred debt securities of any series or subordinated debt securities of any series might be deemed for U.S. federal income tax purposes to be an exchange by the beneficial owners of such securities for new debt securities, which could result in recognition of taxable gain or loss for these purposes and possible other adverse tax consequences for such beneficial owners that are U.S. taxpayers. U.S. beneficial owners should consult their tax advisors regarding the U.S. federal, state and local income tax consequences of an assumption.

Governing Law

The debt securities and the indentures will be governed by and construed in accordance with the laws of the State of New York (without giving effect to the choice of law provisions), except that the authorization and execution by Banco Santander of the indentures and the debt securities, certain provisions of the senior non preferred debt securities and the senior non preferred debt indenture relating to the ranking of the senior non preferred debt securities and certain provisions of the subordinated debt securities and the subordinated indenture related to the subordination of the subordinated debt securities shall be governed by and construed in accordance with Spanish law.

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Agreement and Acknowledgement With Respect to the Exercise of the Bail-in Power

Notwithstanding any other term of the debt securities of any series or any other agreements, arrangements, or understandings between Banco Santander and any holder of the debt securities of any series, by its acquisition of the debt securities of any series, each holder (which, for the purposes of this clause, includes each holder of a beneficial interest in the debt securities of any series) acknowledges, accepts, consents to and agrees:

(i) to be bound by the effect of the exercise of the Bail-in Power by the Relevant Resolution Authority, which may include and result in any of the following, or some combination thereof:

- the reduction of all, or a portion, of the Amounts Due on a permanent basis;

- the conversion of all, or a portion, of the Amounts Due into Common Equity Tier 1 Instruments, other securities or other obligations of Banco Santander or another person (and the issue to the holder of such Common Equity Tier 1 Instruments, securities or obligations), including by means of an amendment, modification or variation of the terms of the debt securities, in which case the holder agrees to accept in lieu of its rights under such debt securities any such Common Equity Tier 1 Instruments, other securities or other obligations of Banco Santander or another person;

- the cancellation of the debt securities or Amounts Due;

- the amendment or alteration of the maturity of the debt securities or amendment of the interest payable on the debt securities, or the date on which the interest becomes payable, including by suspending payment for a temporary period; and

(ii) that the terms of the debt securities are subject to, and may be varied, if necessary, to give effect to, the exercise of the Bail-in Power by the Relevant Resolution Authority.

The exercise of the Bail-in Power by the Relevant Resolution Authority with respect to the debt securities shall not constitute a Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default and the terms and conditions of the debt securities shall continue to apply in relation to the residual principal amount of, or outstanding amount payable with respect to, the debt securities subject to any modification of the amount of distributions payable to reflect the reduction of the principal amount, and any further modification of the terms that the Relevant Resolution Authority may decide in accordance with applicable laws and regulations relating to the resolution of credit institutions, investment firms and/or Group entities incorporated in the relevant member state.

No repayment or payment of the Amounts Due, if any, on the debt securities of any series, will become due and payable or be paid after the exercise of any Bail-in Power by the Relevant Resolution Authority if and to the extent such amounts have been reduced, converted, cancelled, amended or altered as a result of such exercise.

By its acquisition of the debt securities of any series, each holder of the debt securities of such series, (which, for the purposes of this clause, includes each holder of a beneficial interest in the debt securities of such series), to the extent permitted by the Trust Indenture Act of 1939 (“Trust Indenture Act”), will waive any and all claims, in law and/or in equity, against the Trustee for, agree not to initiate a suit against the Trustee in respect of, and agree that the Trustee will not be liable for, any action that the Trustee takes, or abstains from taking, in either case in accordance with the exercise of the Bail-in Power by the Relevant Resolution Authority with respect to the debt securities of such series.

Additionally, by its acquisition of the debt securities of any series, each holder of the debt securities of such series acknowledges and agrees that, upon the exercise of the Bail-in Power by the Relevant Resolution Authority:

(i) the Trustee will not be required to take any further directions from the holders of the debt securities of such series with respect to any portion of the debt securities of such series that are written-down, converted to

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equity and/or cancelled under the relevant indenture, which authorizes holders of a majority in aggregate outstanding principal amount of the debt securities of such series to direct certain actions relating to the debt securities of such series; and

(ii) the relevant indenture will not impose any duties upon the Trustee whatsoever with respect to the exercise of the Bail-in Power by the Relevant Resolution Authority;

provided, however, that notwithstanding the exercise of the Bail-in Power by the Relevant Resolution Authority, so long as the debt securities of any series remain outstanding, there will at all times be a Trustee for the debt securities of such series in accordance with the relevant indenture, and the resignation and/or removal of the Trustee and the appointment of a successor Trustee will continue to be governed by the relevant indenture, including to the extent no additional supplemental indenture or amendment is agreed upon in the event the debt securities of such series remain outstanding following the completion of the exercise of the Bail-in Power.

By its acquisition of the debt securities of any series, each holder of the debt securities of such series acknowledges and agrees that neither a cancellation or deemed cancellation of the principal or interest (in each case, in whole or in part), nor the exercise of the Bail-in Power by the Relevant Resolution Authority with respect to the debt securities of such series will give rise to a default for purposes of Section 315(b) (Notice of Default) and Section 315(c) (Duties of the Trustee in Case of Default) of the Trust Indenture Act.

By purchasing the debt securities of any series, each holder (including each beneficial owner) of the debt securities of such series shall be deemed to have authorized, directed and requested DTC and any direct participant in DTC or other intermediary through which it holds the debt securities of such series to take any and all necessary action, if required, to implement the exercise of the Bail-in Power with respect to the debt securities of such series as it may be imposed, without any further action or direction on the part of such holder.

Each holder of the debt securities also acknowledges and agrees that the foregoing description of the Bail-in Power and its exercise is exhaustive on the matters described herein to the exclusion of any other agreements, arrangements or understandings relating to the application of any Bail-in Power to the debt securities.

Discharge, Defeasance and Covenant Defeasance

Banco Santander may discharge certain obligations to holders of any series of debt securities that have not already been delivered to the Trustee for cancellation and that have become due and payable, will become due and payable at their stated maturity within one year or, if redeemable at the option of Banco Santander, are called for redemption within one year, by depositing or causing to be deposited with the Trustee, in trust, funds in an amount sufficient, without reinvestment, in the opinion of an internationally recognized firm of independent public accountants, to pay and discharge the entire indebtedness on the debt securities of such series, including principal, interest, premium and any additional amounts to the date of such deposit (if the debt securities of such series have become due and payable) or to the maturity date of the debt securities of such series, as the case may be.

Banco Santander may also elect to have its obligations under the relevant indenture discharged with respect to the outstanding debt securities of any series (“legal defeasance”). Legal defeasance means that Banco Santander will be deemed to have paid and discharged the entire indebtedness represented by the outstanding debt securities of such series under the relevant indenture, except for:

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In addition, Banco Santander may elect to have its obligations released with respect only to certain covenants in the relevant indentures (“covenant defeasance”). Any omission to comply with any obligations so released will not constitute a default or an Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable, with respect to the debt securities of any series.

In order to exercise either legal defeasance or covenant defeasance with respect to outstanding debt securities of or within any series:

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Unless otherwise provided in the relevant prospectus supplement, if, after Banco Santander has deposited funds or U.S. government obligations to effect legal defeasance or covenant defeasance with respect to the debt securities of any series,

the indebtedness represented by the debt securities of such series shall be deemed to have been and will be fully discharged and satisfied through the payment of the principal or interest, premium, and any additional amounts on the debt securities of such series as they becomes due out of the proceeds yielded by converting the amount or other property so deposited into the currency in which the debt securities of such series become payable as a result of such election or such conversion event based on the applicable market exchange rate for such currency in effect on the second business day prior to such payment date, except, with respect to a conversion event, for such foreign currency in effect at the time of the conversion event.

A “conversion event” means the cessation of use of (i) a foreign currency both by the government of the country which issued such currency and for the settlement of transactions by a central bank or other public institutions of or within the international banking community, or (ii) the euro both within the European monetary system and for the settlement of transactions by public institutions of or within the EU.

In the event Banco Santander effects covenant defeasance with respect to any series of debt securities and the debt securities of such series are declared due and payable because of the occurrence of any Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable, the amount in money and U.S. government obligations deposited in trust will be sufficient to pay amounts due on the debt securities of such series at the time of their stated maturity. They may not, however, be sufficient to pay amounts due on the debt securities of such series at the time of the acceleration resulting from such Senior Preferred Debt Security Event of Default, Senior Non Preferred Debt Security Event of Default or Subordinated Debt Security Event of Default, as applicable. In this case, Banco Santander will remain liable to make payment of such amounts due at the time of acceleration.

The relevant prospectus supplement may further describe the provisions permitting legal defeasance or covenant defeasance, including any modifications to the provisions described above, with respect to the debt securities of a particular series.

Upon the exercise of the Bail-in Power with respect to a series of debt securities which results in the cancellation, or the conversion into other securities, of all the principal amount of, and interest on, the debt securities of such series or the debt securities of such series otherwise ceasing to be outstanding, the relevant indenture shall be satisfied and discharged as to such series.

Limitation on Suits

No holder of debt securities will be entitled to proceed directly against Banco Santander, except as described below.

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Subject to any further limitations provided in the relevant prospectus supplement and supplemental indenture establishing any series of debt securities, before a holder of the debt securities may bypass the Trustee and bring its own lawsuit or other formal legal action or take other steps to enforce its rights or protect its interests relating to the debt securities, the following must occur:

Notwithstanding any other provision of the debt securities indenture or the relevant debt securities, the right of any holder of debt securities to receive payment of the principal amount of and interest on, the debt securities, on or after the due dates thereof or to institute suit for the enforcement of any such payment on or after such respective dates, will not be impaired or affected without the consent of such holder.

Notices

All notices to holders of registered debt securities shall be validly given if in writing and mailed, first-class postage prepaid, to them at their respective addresses in the register maintained by the Trustee.

If and for so long as the debt securities of the relevant series are admitted to trading on a stock exchange, notices will also be given in accordance with any applicable requirements of such stock exchange.

No Obligations to Beneficial Owners

None of Banco Santander, the Trustee, the paying agent or the debt security registrar shall have any responsibility or obligation to any beneficial owner in a global security, an agent member or other person with respect to the accuracy of the records of the depositary or its nominee or of any agent member, with respect to any ownership interest in the debt securities or with respect to the delivery to any agent member, beneficial owner or other person (other than the depository) of any notice (including any notice of redemption) or the payment of any amount, under or with respect to such debt securities. All notices and communications to be given to the holders and all payments to be made to holders under the debt securities and the respective indenture shall be given or made only to or upon the order of the registered holders (which shall be the depositary or its nominee in the case of the global security). The rights of beneficial owners in the global security shall be exercised only through the depositary subject to the applicable procedures. Banco Santander, the Trustee, the paying agent and the debt security registrar shall be entitled to rely and shall be fully protected in relying upon information furnished by the depositary with respect to its members, participants and any beneficial owners. Banco Santander, the Trustee, the paying agent and the debt security registrar shall be entitled to deal with the depositary, and any nominee thereof, that is the registered holder of any global security for all purposes of the indenture relating to such global security (including the payment of principal, premium, if any, and interest and additional amounts, if any, and the giving of instructions or directions by or to the owner or holder of a beneficial ownership interest in such global security) as the sole holder of such global security and shall have no obligations to the beneficial owners thereof. None of Banco Santander, the Trustee, the paying agent or the debt security

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registrar shall have any responsibility or liability for any acts or omissions of the depositary with respect to such global security, for the records of any such depositary, including records in respect of beneficial ownership interests in respect of any such global security, for any transactions between the depositary and any agent member or between or among the depositary, any such agent member and/or any holder or owner of a beneficial interest in such global security, or for any transfers of beneficial interests in any such global security.

Notwithstanding the foregoing, with respect to any global security, nothing herein shall prevent Banco Santander, the Trustee, or any agent of Banco Santander or the Trustee from giving effect to any written certification, proxy or other authorization furnished by any depositary (or its nominee), as a holder, with respect to such global security or shall impair, as between such depositary and owners of beneficial interests in such global security, the operation of customary practices governing the exercise of the rights of such depositary (or its nominee) as holder of such global security.

Subsequent Holders’ Agreement

Holders and beneficial owners of the debt securities of any series or beneficial interests therein that acquire the debt securities of such series in the secondary market shall be deemed to acknowledge, agree to be bound by and consent to the same provisions specified herein to the same extent as the holders and beneficial owners of the debt securities of such series that acquire the debt securities of such series upon their initial issuance, including, without limitation, with respect to the acknowledgment and agreement to be bound by and consent to the terms of the debt securities of such series, including in relation to the Bail-in Power.

The Trustee

The Bank of New York Mellon, London Branch, is the Trustee under the indentures with respect to the debt securities. The Trustee shall have and be subject to all the duties and responsibilities specified with respect to an indenture Trustee under the Trust Indenture Act. Subject to the provisions of the relevant indentures and the Trust Indenture Act, the Trustee is under no obligation to exercise any of the powers vested in it by the indentures at the request of any holder of debt securities, unless offered indemnity satisfactory to the Trustee in its sole discretion by the holder against the costs, expense and liabilities which might be incurred thereby. Banco Santander and certain of its subsidiaries maintain deposit accounts and conduct other banking transactions with The Bank of New York Mellon in the ordinary course of their business. The Bank of New York Mellon is also the Principal Paying Agent with respect to Banco Santander’s debt securities.

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DESCRIPTION OF CONTINGENT CONVERTIBLE CAPITAL SECURITIES

The following is a summary of the general terms that will apply to any contingent convertible capital securities that may be offered by Banco Santander.

Each time that Banco Santander issues contingent convertible capital securities, it will file a prospectus supplement and/or free writing prospectus with the SEC, which investors should read carefully. The prospectus supplement and/or free writing prospectus will summarize specific financial terms of your security and may contain additional or different terms of those contingent convertible capital securities to those described in this prospectus. All references in this prospectus to a prospectus supplement in respect of any series of securities include references to a free writing prospectus if a free writing prospectus is filed to set forth any terms of such series. The terms presented here, together with the terms contained in the prospectus supplement, will be a description of the material terms of the contingent convertible capital securities, but if there is any inconsistency between the terms presented here and those in the prospectus supplement, those in the prospectus supplement will apply and will replace those presented here. Therefore, the statements made below in this section may not apply to each investor’s contingent convertible capital security. Contingent convertible capital securities will be issued by Banco Santander under a contingent convertible capital securities indenture. The contingent convertible capital securities indenture is a contract between Banco Santander, as issuer, and The Bank of New York Mellon, London Branch as Trustee. The contingent convertible capital securities indenture does not limit Banco Santander’s ability to incur additional indebtedness, including the issuance of further contingent convertible capital securities. Investors should also read the contingent convertible capital securities indenture and any related supplemental indenture establishing such contingent convertible capital convertible securities, which have been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part.

General

The contingent convertible capital securities are Banco Santander’s perpetual subordinated convertible debt securities mandatorily convertible into Banco Santander’s ordinary shares only upon the occurrence of certain events. The contingent convertible capital securities are not deposits and are not insured or guaranteed by the U.S. Federal Deposit Insurance Corporation or any other government agency of the United States or the Kingdom of Spain.

Banco Santander may issue contingent convertible capital securities in one or more series. The relevant prospectus supplement for any particular series of contingent convertible capital securities will describe the terms of the offered contingent convertible capital securities, including, but not limited to, some or all of the following terms, to the extent such terms differ from or are in addition to those set forth in this prospectus:

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