HPS John Hancock Preferred Income Fund III

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811- 21287

John Hancock Preferred Income Fund III

(Exact name of registrant as specified in charter)

200 Berkeley Street, Boston, Massachusetts 02116 (Address of principal executive offices) (Zip code)

Salvatore Schiavone

Treasurer

200 Berkeley Street

Boston, Massachusetts 02116

(Name and address of agent for service)

Registrant's telephone number, including area code: 617-543-9637

ITEM 1. REPORTS TO STOCKHOLDERS.

ITEM 2. CODE OF ETHICS.

As of the end of the period, July 31, 2023, the registrant has adopted a code of ethics, as defined in Item 2 of Form N-CSR, that applies to its Chief Executive Officer, Chief Financial Officer and Treasurer (respectively, the principal executive officer, the principal financial officer and the principal accounting officer, the "Covered Officers"). A copy of the code of ethics is filed as an exhibit to this Form N-CSR.

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Frances G. Rathke is the audit committee financial expert and is "independent", pursuant to general instructions on Form N-CSR Item 3.

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

(a) Audit Fees

The aggregate fees billed for professional services rendered by the principal accountant(s) for the audit of the registrant's annual financial statements or services that are normally provided by the accountant(s) in connection with statutory and regulatory filings or engagements amounted to $55,552 for the fiscal year ended July 31, 2023 and $54,196 for the fiscal year ended July 31, 2022. These fees were billed to the registrant and were approved by the registrant's audit committee.

(b) Audit-Related Services

Audit-related fees for assurance and related services by the principal accountant are billed to the registrant or to the registrant's investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the adviser ("control affiliates") that provides ongoing services to the registrant amounted to $5 for the fiscal year ended July 31, 2023 and $212 for the fiscal year ended July 31, 2022. The nature of the services provided was related to a software licensing fee and servicer provided internal controls reviews.

(c) Tax Fees

The aggregate fees billed for professional services rendered by the principal accountant(s) for the tax compliance, tax advice and tax planning ("tax fees") amounted to $5,253 for the fiscal year ended July 31, 2023 and $4,110 for the fiscal year ended July 31, 2022. The nature of the services comprising the tax fees was the review of the registrant's tax returns and tax distribution requirements. These fees were billed to the registrant and were approved by the registrant's audit committee.

(d) All Other Fees

The nature of the services comprising all other fees is advisory services provided to the investment manager. These fees were approved by the registrant's audit committee. All other fees billed to the registrant for products and services provided by the principal accountant were $0 for the fiscal year ended July 31, 2023 and $362 for the fiscal year ended July 31, 2022.

(e)(1) Audit Committee Pre-Approval Policies and Procedures:

The trust's Audit Committee must pre-approve all audit and non-audit services provided by the independent registered public accounting firm (the "Auditor") relating to the operations or financial reporting of the funds. Prior to the commencement of any audit or non-audit services to a fund, the Audit Committee reviews the services to determine whether they are appropriate and permissible under applicable law.

The trust's Audit Committee has adopted policies and procedures to, among other purposes, provide a framework for the Committee's consideration of audit-related and non-audit services by

the Auditor. The policies and procedures require that any audit-related and non-audit service provided by the Auditor and any non-audit service provided by the Auditor to a fund service provider that relates directly to the operations and financial reporting of a fund are subject to approval by the Audit Committee before such service is provided. Audit-related services provided by the Auditor that are expected to exceed $25,000 per instance/per fund are subject to specific pre-approval by the Audit Committee. Tax services provided by the Auditor that are expected to exceed $30,000 per instance/per fund are subject to specific pre-approval by the Audit Committee.

All audit services, as well as the audit-related and non-audit services that are expected to exceed the amounts stated above, must be approved in advance of provision of the service by formal resolution of the Audit Committee. At the regularly scheduled Audit Committee meetings, the Committee reviews a report summarizing the services, including fees, provided by the Auditor.

(e)(2) Services approved pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X:

Audit-Related Fees, Tax Fees and All Other Fees:

There were no amounts that were approved by the Audit Committee pursuant to the de minimis exception under Rule 2-01 of Regulation S-X.

(f)According to the registrant's principal accountant, for the fiscal year ended July 31, 2023, the percentage of hours spent on the audit of the registrant's financial statements for the most recent fiscal year that were attributed to work performed by persons who were not full-time, permanent employees of principal accountant was less than 50%.

(g)The aggregate non-audit fees billed by the registrant's accountant(s) for services rendered to the registrant and rendered to the registrant's control affiliates for each of the last two fiscal years of the registrant were $1,452,111 for the fiscal year ended July 31, 2023 and $1,125,962 for the fiscal year ended July 31, 2022.

(h)The audit committee of the registrant has considered the non-audit services provided by the registrant's principal accountant(s) to the control affiliates and has determined that the services that were not pre-approved are compatible with maintaining the principal accountant(s)' independence.

(i)Not applicable

(j)Not applicable

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

The registrant has a separately-designated standing audit committee comprised of independent trustees. The members of the audit committee are as follows:

Frances G. Rathke – Chairperson

Peter S. Burgess – Retired effective December 31, 2022

William H. Cunningham

Patricia Lizarraga, effective September 20, 2022 - September 21, 2023

Hassell H. McClellan, effective September 26, 2023

ITEM 6. SCHEDULE OF INVESTMENTS.

(a)Not applicable.

(b)Not applicable.

ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED- END MANAGEMENT INVESTMENT COMPANIES.

See attached exhibit "Proxy Voting Policies and Procedures".

ITEM 8.

PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Information about the portfolio managers

Management Biographies

Below is a list of the Manulife Investment Management (US) LLC ("Manulife IM (US)") portfolio managers who share joint responsibility for the day-to-day investment management of the Fund. It provides a brief summary of their business careers over the past five years. The information provided is as of the filing date of this N-CSR.

Joseph H. Bozoyan, CFA

Portfolio Manager

Managing Director and Senior Investment Analyst, Intrinsic Value Team,

Manulife Investment Management (US) LLC (2014–2015)

Director and Senior Investment Manager, Intrinsic Value Team,

Manulife Investment Management (US) LLC (2011–2014)

Began business career in 1993

Managed the fund since 2015

James Gearhart, CFA Managing Director and Associate Portfolio Manager

Manulife Investment Management (US) LLC since 2022

Began business career in 2011

Managed the Fund since 2022

Jonas Grazulis, CFA

Managing Director and Associate Portfolio Manager

Manulife Investment Management (US) LLC since 2022

Began business career in 2011

Managed the Fund since 2022

Caryn E. Rothman, CFA

Managing Director and Portfolio Manager

Manulife Investment Management (US) LLC since 1996

Began business career in 1996

Managed the Fund since 2022

Other Accounts the Portfolio Managers are Managing

The table below indicates for each portfolio manager information about the accounts over which the portfolio manager has day-to-day investment responsibility. All information on the number of accounts and total assets in the table is as of July 31, 2023. For purposes of the table, "Other Pooled Investment Vehicles" may include investment partnerships and group trusts, and "Other Accounts" may include separate accounts for institutions or individuals, insurance company general or separate accounts, pension funds and other similar institutional accounts.

Number and value of accounts within the total accounts that are subject to a performance-based advisory fee: None .

Conflicts of Interest. When a portfolio manager is responsible for the management of more than one account, the potential arises for the portfolio manager to favor one account over another. The principal types of potential conflicts of interest that may arise are discussed below. For the reasons outlined below, the Fund does not believe that any material conflicts are likely to arise out of a portfolio manager's responsibility for the management of the Fund as well as one or more other accounts. The Advisor and Subadvisor have adopted procedures that are intended to monitor compliance with the policies referred to in the following paragraphs. Generally, the risks of such conflicts of interests are increased to the extent that a portfolio manager has a financial incentive to favor one account over another. The Advisor and Subadvisor have structured their compensation arrangements in a manner that is intended to limit such potential for conflicts of interests. See "Compensation of Portfolio Managers" below.

•A portfolio manager could favor one account over another in allocating new investment opportunities that have limited supply, such as initial public offerings and private placements. If, for example, an initial public offering that was expected to appreciate in value significantly shortly after the offering was allocated to a single account, that account may be expected to have better investment performance than other accounts that did not receive an allocation on the initial public offering. The Subadvisor has policies that require a portfolio manager to allocate such investment opportunities in an equitable manner and generally to allocate such investments proportionately among all accounts with similar investment objectives.

•A portfolio manager could favor one account over another in the order in which trades for the accounts are placed. If a portfolio manager determines to purchase a security for more than one account in an aggregate amount that may influence the market price of the security, accounts that purchased or sold the security first may receive a more favorable price than accounts that made subsequent transactions. The less liquid the market for the security or the greater the percentage that the proposed aggregate purchases or sales represent of average daily trading volume, the greater the potential for accounts that make subsequent purchases or sales to receive a less favorable price. When a portfolio manager intends to trade the same security for more than one account, the policies of the Subadvisor generally require that such trades be "bunched," which means that the trades for the individual accounts are aggregated and each account receives the same price. There are some types of accounts as to which bunching may not be possible for contractual reasons (such as directed brokerage arrangements). Circumstances may also arise where the trader believes that bunching the orders may not result in the best possible price. Where those accounts or circumstances are involved, the Subadvisor will place the order in a manner intended to result in as favorable a price as possible for such client.

•A portfolio manager could favor an account if the portfolio manager's compensation is tied to the performance of that account rather than all accounts managed by the portfolio manager. If, for example, the portfolio manager receives a bonus based upon the performance of certain accounts relative to a benchmark while other accounts are disregarded for this purpose, the portfolio manager will have a financial incentive to seek to have the accounts that determine the portfolio manager's bonus achieve the best possible performance to the possible detriment of other accounts. Similarly, if the Subadvisor receives a performance-based advisory fee, the portfolio manager may favor that account, whether or not the performance of that account directly determines the portfolio manager's compensation. The investment performance on specific accounts is not a factor in determining the portfolio manager's compensation. See "Compensation of Portfolio Managers" below. Neither the Advisor nor the Subadvisor receives a performance-based fee with respect to any of the accounts managed by the portfolio managers.

•A portfolio manager could favor an account if the portfolio manager has a beneficial interest in the account, in order to benefit a large client or to compensate a client that had poor returns. For example, if the portfolio manager held an interest in an investment partnership that was one of the accounts managed by the portfolio manager, the portfolio manager would have an economic incentive to favor the account in which the portfolio manager held an interest. The Subadvisor imposes certain trading restrictions and reporting requirements for accounts in which a portfolio manager or certain family members have a personal interest in order to confirm that such accounts are not favored over other accounts.

•If the different accounts have materially and potentially conflicting investment objectives or strategies, a conflict of interest may arise. For example, if a portfolio manager purchases a security for one account and sells the same security short for another account, such trading pattern could disadvantage either the account that is long or short. In making portfolio manager assignments, the Subadvisor seeks to avoid such potentially conflicting situations. However, where a portfolio manager is responsible for accounts with differing investment objectives and policies, it is possible that the portfolio manager will conclude that it is in the best interest of one account to sell a portfolio security while another account continues to hold or increase the holding in such security.

Compensation of Portfolio Managers. The Subadvisor has adopted a system of compensation for portfolio managers and others involved in the investment process that is applied systematically among investment professionals. At the Subadvisor, the structure of compensation of investment professionals is currently composed of the following basic components: base salary and an annual investment bonus plan as well as customary benefits that are offered generally to all full- time employees of the Subadvisor. The following describes each component of the compensation package for the individuals identified as a portfolio manager for the Funds.

•Base salary. Base compensation is fixed and normally reevaluated on an annual basis. The Subadvisor seeks to set compensation at market rates, taking into account the experience and responsibilities of the investment professional.

•Investment Bonus Plan. Only investment professionals are eligible to participate in the Investment Bonus Plan. Under the plan, investment professionals are eligible for an annual bonus. The plan is intended to provide a competitive level of annual bonus compensation that is tied to the investment professional achieving superior investment performance and aligns the financial incentives of the Subadvisor and the investment professional. Any bonus under the plan is completely discretionary, with a maximum annual bonus that may be well in excess of base salary. Payout of a

portion of this bonus may be deferred for up to five years. While the amount of any bonus is discretionary, the following factors are generally used in determining bonuses under the plan:

•Investment Performance: The investment performance of all accounts managed by the investment professional over one- and three-and five-year periods are considered, and no specific benchmark is used to measure performance. With respect to fixed income accounts, relative yields are also used to measure performance.

•The Profitability of the Subadvisor: The profitability of the Subadvisor and its parent company are also considered in determining bonus awards.

•Non-Investment Performance: To a lesser extent, intangible contributions, including the investment professional's support of client service and sales activities, new fund/strategy idea generation, professional growth and development, and management, where applicable, are also evaluated when determining bonus awards.

•In addition to the above, compensation may also include a revenue component for an investment team derived from a number of factors including, but not limited to, client assets under management, investment performance, and firm metrics.

•Options and Stock Grants. A limited number of senior investment professionals may receive options to purchase shares of Manulife Financial stock. Generally, such option would permit the investment professional to purchase a set amount of stock at the market price on the date of grant. The option can be exercised for a set period (normally a number of years or until termination of employment) and the investment professional would exercise the option if the market value of Manulife Financial stock increases. Some investment professionals may receive restricted stock grants, where the investment professional is entitled to receive the stock at no or nominal cost, provided that the stock is forgone if the investment professional's employment is terminated prior to a vesting date.

•Deferred Incentives. Investment professionals may receive deferred incentives which are fully invested in strategies managed by the team/individuals as well as other Manulife Asset Management strategies.

The Subadvisor also permits investment professionals to participate on a voluntary basis in a deferred compensation plan, under which the investment professional may elect on an annual basis to defer receipt of a portion of their compensation until retirement. Participation in the plan is voluntary.

Share Ownership by Portfolio Managers. For purposes of these tables, "similarly managed accounts" include all accounts that are managed (i) by the same portfolio managers that are jointly and primarily responsible for the day-to-day management of the Fund; and (ii) with an investment style, objective, policies and strategies substantially similar to those that are used to manage the Fund.

ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

None.

ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

The registrant has adopted procedures by which shareholders may recommend nominees to the registrant's Board of Trustees. A copy of the procedures is filed as an exhibit to this Form N-CSR. See attached "John Hancock Funds – Nominating and Governance Committee Charter".

ITEM 11. CONTROLS AND PROCEDURES.

(a)Based upon their evaluation of the registrant's disclosure controls and procedures as conducted within 90 days of the filing date of this Form N-CSR, the registrant's principal executive officer and principal financial officer have concluded that those disclosure controls and procedures provide reasonable assurance that the material information required to be disclosed by the registrant on this report is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission's rules and forms.

(b)There were no changes in the registrant's internal control over financial reporting that occurred during the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.

ITEM 12. DISCLOSURE OF SECURITIES LENDING ACTIVITIES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

The Fund did not participate directly in securities lending activities. See Note 7 to financial statements in Item 1.

ITEM 13. EXHIBITS.

(a)(1) Code of Ethics for Covered Officers is attached.

(a)(2) Separate certifications for the registrant's principal executive officer and principal financial officer, as required by Section 302 of the Sarbanes-Oxley Act of 2002 and Rule 30a-2(a) under the Investment Company Act of 1940, are attached.

(b)Separate certifications for the registrant's principal executive officer and principal financial officer, as required by 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, and Rule 30a-2(b) under the Investment Company Act of 1940, are attached. The certifications furnished pursuant to this paragraph are not deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section. Such certifications are not deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934, except to the extent that the Registrant specifically incorporates them by reference.

(c)(1) Proxy Voting Policies and Procedures are attached.

(c)(2) Submission of Matters to a Vote of Security Holders is attached. See attached "John Hancock Funds - Governance Committee Charter".

(c)(3) Registrant's notice to shareholders pursuant to Registrant's exemptive order granting an exemption from Section 19(b) of the Investment Company Act of 1940, as amended and Rule 19b-1 thereunder regarding distributions made pursuant to the Registrant's Managed Distribution Plan.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

John Hancock Preferred Income Fund III

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Each of the Covered Officers should adhere to a high standard of business ethics and should be sensitive to situations that may give rise to actual as well as apparent conflicts of interest.

II.Covered Officers Should Handle Ethically Actual and Apparent Conflicts of Interest Overview

A "conflict of interest" occurs when a Covered Officer's private interest interferes with the interests of, or his service to, the Fund. For example, a conflict of interest would arise if a Covered Officer, or a member of his family, receives improper personal benefits as a result of his position with the Fund. Certain conflicts of interest arise out of the relationships between the Covered Officers and the Fund and already are subject to conflict of interest provisions in the Investment Company Act of 1940, as amended (the "Investment Company Act") and the Investment Advisers Act of 1940, as amended (the "Investment Advisers Act"). For example, Covered Officers may not individually engage in certain transactions (such as the purchase or sale of securities or other property) with the Fund because of their status as "affiliated persons" of the Fund. Each of the Covered Officers is an officer or employee of the investment adviser or a service provider ("Service Provider") to the Fund. The Fund's, the investment adviser's and the Service Provider's compliance programs and procedures are designed to prevent, or identify and correct, violations of these provisions. This Code does not, and is not intended to, repeat or replace these programs and procedures, and such conflicts fall outside of the parameters of this Code.

Although typically not presenting an opportunity for improper personal benefit, conflicts arise from, or as a result of, the contractual relationship between the Fund and the investment adviser and the Service Provider of which the Covered Officers are also officers or employees. As a result, this Code recognizes that the Covered Officers will, in the normal course of their duties (whether formally for the Fund, for the investment adviser or for the Service Provider), be involved in establishing policies and implementing decisions which will have different effects on the investment adviser, the Service Provider and the Fund. The participation of the Covered Officers in such activities is inherent in the contractual relationship between the Fund and the investment adviser and the Service Provider and is consistent with the performance by the Covered Officers of their duties as officers of the Fund. Thus, if such participation is performed in conformity with the provisions of the Investment Company Act and the Investment Advisers Act, it will be deemed to have been handled ethically. In addition, it is recognized by the Fund's Board of Trustees/Directors (the "Board") that the Covered Officers may also be officers or employees of one or more other investment companies covered by other Codes.

Other conflicts of interest are covered by the Code, even if such conflicts of interest are not subject to provisions in the Investment Company Act and the Investment Advisers Act. The following list provides examples of conflicts of interest under the Code, but the Covered Officers should keep in mind that these examples are not exhaustive. The overarching principle is that the personal interest of a Covered Officer should not be placed improperly before the interest of the Fund.

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Each Covered Officer must:

not use his/her personal influence or personal relationships improperly to influence investment decisions or financial reporting by the Fund whereby the Covered Officer would benefit personally to the detriment of the Fund;

not cause the Fund to take action, or fail to take action, for the individual personal benefit of the Covered Officer rather than for the benefit of the Fund; and

not use material non-public knowledge of portfolio transactions made or contemplated for the Fund to trade personally or cause others to trade personally in contemplation of the market effect of such transactions.

Additionally, conflicts of interest may arise in other situations, the propriety of which may be discussed, if material, with the Fund's Chief Compliance Officer ("CCO"). Examples of these include:

serve as a director/trustee on the board of any public or private company;

the receipt of any non-nominal gifts;

the receipt of any entertainment from any company with which the Fund has current or prospective business dealings unless such entertainment is business-related, reasonable in cost, appropriate as to time and place, and not so frequent as to raise any question of impropriety (or other formulation as the Fund already uses in another code of conduct);

any ownership interest in, or any consulting or employment relationship with, any of the Fund's service providers, other than its investment adviser, any sub-adviser, principal underwriter, administrator or any affiliated person thereof; and

a direct or indirect financial interest in commissions, transaction charges or spreads paid by the Fund for effecting portfolio transactions or for selling or redeeming shares other than an interest arising from the Covered Officer's employment, such as compensation or equity ownership.

III.Disclosure & Compliance

Each Covered Officer should familiarize himself or herself with the disclosure requirements generally applicable to the Fund;

Each Covered Officer should not knowingly misrepresent, or cause others to misrepresent, facts about the Fund to others, whether within or outside the Fund, including to the Fund's directors and auditors, and to governmental regulators and self- regulatory organizations;

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Each Covered Officer should, to the extent appropriate within his/her area of responsibility, consult with other officers and employees of the Fund and the Fund's adviser or any sub-adviser with the goal of promoting full, fair, accurate, timely and understandable disclosure in the reports and documents the Fund files with, or submits to, the SEC and in other public communications made by the Fund; and

It is the responsibility of each Covered Officer to promote compliance with the standards and restrictions imposed by applicable laws, rules and regulations.

IV. Reporting & Accountability

Each Covered Officer must:

upon adoption of the Code (or thereafter as applicable, upon becoming an Covered Officer), affirm in writing to the Fund's CCO that he/she has received, read, and understands the Code;

annually thereafter affirm to the Fund's CCO that he/she has complied with the requirements of the Code;

not retaliate against any employee or Covered Officer or their affiliated persons for reports of potential violations that are made in good faith;

notify the Fund's CCO promptly if he/she knows of any violation of this Code (Note: failure to do so is itself a violation of this Code); and

report at least annually any change in his/her affiliations from the prior year.

The Fund's CCO is responsible for applying this Code to specific situations in which questions are presented under it and has the authority to interpret this Code in any particular situation. However, any approvals or waivers sought by the Principal Executive Officer will be considered by the Fund's Board or the Compliance Committee thereof (the "Committee").

The Fund will follow these procedures in investigating and enforcing this Code:

the Fund's CCO will take all appropriate action to investigate any potential violations reported to him/her;

if, after such investigation, the CCO believes that no violation has occurred, the CCO is not required to take any further action;

any matter that the CCO believes is a violation will be reported to the Board or, if applicable, Compliance Committee;

if the Board or, if applicable, Compliance Committee concurs that a violation has occurred, the Board, either upon its determination of a violation or upon

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recommendation of the Compliance Committee, if applicable, will consider appropriate action, which may include review of, and appropriate modifications to, applicable policies and procedures; notification to appropriate personnel of the Service Provider or the investment adviser or its board; or a recommendation to dismiss the Registrant's Executive Officer;

the Board, or if applicable the Compliance Committee, will be responsible for granting waivers, as appropriate; and

any changes to or waivers of this Code will, to the extent required, be disclosed as provided by SEC rules.

V.Other Policies & Procedures

This Code shall be the sole code of ethics adopted by the Fund for purposes of Section 406 of the Sarbanes-Oxley Act of 2002 and the rules and forms applicable to registered investment companies thereunder. Insofar as other policies or procedures of the Fund, the Fund's adviser, any sub- adviser, principal underwriter or other service providers govern or purport to govern the behavior or activities of the Covered Officers who are subject to this Code, they are superseded by this Code to the extent that they overlap or conflict with the provisions of this Code. The Fund's and its investment adviser's codes of ethics under Rule 204A-1 under the Investment Advisers Act and Rule 17j-1 under the Investment Company Act, respectively, are separate requirements applying to the Covered Officers and others and are not part of this Code.

VI. Amendments

Any amendments to this Code, other than amendments to Exhibit A, must be approved or ratified by a majority vote of the Fund's Board, including a majority of independent directors.

VII. Confidentiality

All reports and records prepared or maintained pursuant to this Code will be considered confidential and shall be maintained and protected accordingly. Except as otherwise required by law or this Code, such matters shall not be disclosed to anyone other than the Fund's Board and its counsel, the investment adviser and the relevant Service Providers.

VIII. Internal Use

The Code is intended solely for the internal use by the Fund and does not constitute an admission, by or on behalf of the Fund, as to any fact, circumstance, or legal conclusion.

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Exhibit A

Persons Covered by this Code of Ethics

(As of June 29, 2023)

John Hancock Variable Insurance Trust

Principal Executive Officer and President – Kristie Feinberg

Principal Financial Officer and Chief Financial Officer – Charles Rizzo

Treasurer – Salvatore Schiavone

John Hancock Funds

Principal Executive Officer and President – Kristie Feinberg

Principal Financial Officer and Chief Financial Officer – Charles Rizzo

Treasurer – Salvatore Schiavone

John Hancock Funds II

Principal Executive Officer and President – Kristie Feinberg

Principal Financial Officer and Chief Financial Officer – Charles Rizzo

Treasurer – Salvatore Schiavone

John Hancock Exchange-Traded Trust

Principal Executive Officer and President – Kristie Feinberg

Principal Financial Officer and Chief Financial Officer – Charles Rizzo

Treasurer – Salvatore Schiavone

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CERTIFICATION

I, Kristie M. Feinberg, certify that:

1.I have reviewed this report on Form N-CSR of the John Hancock Preferred Income Fund III (the "registrant");

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

CERTIFICATION

I, Charles A. Rizzo, certify that:

1.I have reviewed this report on Form N-CSR of the John Hancock Preferred Income Fund III (the "registrant");

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Certification Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of

the Sarbanes-Oxley Act of 2002*

In connection with the attached Report of John Hancock Preferred Income Fund III (the "registrant") on Form N-CSR to be filed with the Securities and Exchange Commission (the "Report"), each of the undersigned officers of the registrant does hereby certify that, to the best of such officer's knowledge:

1.The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the registrant as of, and for, the periods presented in the Report.

/s/ Kristie M. Feinberg

--------------------------------

Kristie M. Feinberg President

Dated: September 26, 2023

/s/ Charles A. Rizzo

---------------------------------

Charles A. Rizzo

Chief Financial Officer

Dated: September 26, 2023

A signed original of this written statement, required by Section 906, has been provided to the registrant and will be retained by the registrant and furnished to the Securities and Exchange Commission or its staff upon request.

*These certifications are being furnished solely pursuant to 18 U.S.C. Section 1350 and are not being filed as part of this Form N-CSR or as a separate disclosure document.

5E: Proxy Voting Policies and Procedures for the Adviser

General Compliance Policies for Trust & Adviser

Section 5: Fiduciary Standards & Affiliated Persons Issues

5E. Advisers Proxy Voting Policy

Overview

The SEC adopted Rule 206(4)-6 under the Advisers Act, which requires investment advisers with voting authority to adopt and implement written policies and procedures that are reasonably designed to ensure that the investment adviser votes client securities in the best interest of clients. The procedures must include how the investment adviser addresses material conflicts that may arise between the interests of the investment adviser and those of its clients. The Advisers are registered investment advisers under the Advisers Act and serve as the investment advisers to the Funds. The Advisers generally retain one or more sub-advisers to manage the assets of the Funds, including voting proxies with respect to a Fund's portfolio securities. From time to time, however, the Advisers may elect to manage directly the assets of a Fund, including voting proxies with respect to such Fund's portfolio securities, or a Fund's Board may otherwise delegate to the Advisers authority to vote such proxies. Rule 206(4)-6 under the Advisers Act requires that a registered investment adviser adopt and implement written policies and procedures reasonably designed to ensure that it votes proxies with respect to a client's securities in the best interest of the client.

Firms are required by Advisers Act Rule 204-2(c)(2) to maintain records of their voting policies and procedures, a copy of each proxy statement that the investment adviser receives regarding client securities, a record of each vote cast by the investment adviser on behalf of a client, a copy of any document created by the investment adviser that was material to making a decision how to vote proxies on behalf of a client, and a copy of each written client request for information on how the adviser voted proxies on behalf of the client, as well as a copy of any written response by the investment adviser to any written or oral client request for information on how the adviser voted that client's proxies.

Investment companies must disclose information about the policies and procedures used to vote proxies on the investment company's portfolio securities and must file the fund's proxy voting record with the SEC annually on Form N-PX.

Pursuant thereto, the Advisers have adopted and implemented these proxy voting policies and procedures (the "Proxy Procedures").

Policy

It is the Advisers' policy to comply with Rule 206(4)-6 and Rule 204-2(c)(2) under the Advisers Act as described above. In general, the Advisers delegate proxy voting decisions to the sub-advisers managing the funds. If an instance occurs where a conflict of interest arises between the shareholders and a particular sub-adviser, however, the Adviser retains the right to influence and/or direct the conflicting proxy voting decisions.

Regulatory Requirement

Rule 206(4)-6 under the Advisers Act

Reporting

Form N-PX

Advisers will provide the Board with notice and a copy of any amendments or revisions to the Procedures and will report quarterly to the Board all material changes to these Proxy Procedures.

The CCO's annual written compliance report to the Board will contain a summary of material changes to the Proxy Procedures during the period covered by the report.

If the Advisers or the Designated Person vote any proxies in a manner inconsistent with either these Proxy Procedures or a Fund's proxy voting policies and procedures, the CCO will provide the Board with a report detailing such exceptions.

Procedure

Fiduciary Duty

The Advisers have a fiduciary duty to vote proxies on behalf of a Fund in the best interest of the Fund and its shareholders.

Voting of Proxies - Advisers

The Advisers will vote proxies with respect to a Fund's portfolio securities when authorized to do so by the Fund and subject to the Fund's proxy voting policies and procedures and any further direction or delegation of authority by the Fund's Board. The decision on how to vote a proxy will be made by the person(s) to whom the Advisers have from time to time delegated such responsibility (the "Designated Person"). The Designated Person may include the Fund's portfolio manager(s) or a Proxy Voting Committee, as described below.

When voting proxies with respect to a Fund's portfolio securities, the following standards will apply:

•The Designated Person will vote based on what it believes is in the best interest of the Fund and its shareholders and in accordance with the Fund's investment guidelines.

•Each voting decision will be made independently. To assist with the analysis of voting issues and/or to carry out the actual voting process the Designated Person may enlist the services of

(1) reputable professionals (who may include persons employed by or otherwise associated with the Advisers or any of its affiliated persons) or (2) independent proxy evaluation services such as Institutional Shareholder Services. However, the ultimate decision as to how to vote a proxy will remain the responsibility of the Designated Person.

•The Advisers believe that a good management team of a company will generally act in the best interests of the company. Therefore, the Designated Person will take into consideration as a key factor in voting proxies with respect to securities of a company that are held by the Fund the quality of the company's management. In general, the Designated Person will vote as recommended by company management except in situations where the Designated Person believes such recommended vote is not in the best interests of the Fund and its shareholders.

•As a general principle, voting with respect to the same portfolio securities held by more than one Fund should be consistent among those Funds having substantially the same investment mandates.

•The Advisers will provide the Fund, from time to time in accordance with the Fund's proxy voting policies and procedures and any applicable laws and regulations, a record of the Advisers' voting of proxies with respect to the Fund's portfolio securities.

Material Conflicts of Interest

In carrying out its proxy voting responsibilities, the Advisers will monitor and resolve potential material conflicts ("Material Conflicts") between the interests of (a) a Fund and (b) the Advisers or any of its affiliated persons. Affiliates of the Advisers include Manulife Financial Corporation and its subsidiaries. Material Conflicts may arise, for example, if a proxy vote relates to matters involving any of these companies or other issuers in which the Advisers or any of their affiliates has a substantial equity or other interest.

If the Advisers or a Designated Person become aware that a proxy voting issue may present a potential

5E. Advisers Proxy Voting Policy

Material Conflict, the issue will be referred to the Advisers' Legal Department and/or the Office of the CCO. If the Legal Department and/or the Office of the CCO, as applicable determines that a potential Material Conflict does exist, a Proxy Voting Committee will be appointed to consider and resolve the issue. The Proxy Voting Committee may make any determination that it considers reasonable and may, if it chooses, request the advice of an independent, third-party proxy service on how to vote the proxy.

Voting Proxies of Underlying Funds of a Fund of Funds

The Advisers or the Designated Person will vote proxies with respect to the shares of a Fund that are held by another Fund that operates as a Fund of Funds") in the manner provided in the proxy voting policies and procedures of the Fund of Funds (including such policies and procedures relating to material conflicts of interest) or as otherwise directed by the board of trustees or directors of the Fund of Funds.

Proxy Voting Committee(s)

The Advisers will from time to time, and on such temporary or longer-term basis as they deem appropriate, establish one or more Proxy Voting Committees. A Proxy Voting Committee shall include the Advisers' CCO and may include legal counsel. The terms of reference and the procedures under which a Proxy Voting Committee will operate will be reviewed from time to time by the Legal and Compliance Department. Records of the deliberations and proxy voting recommendations of a Proxy Voting Committee will be maintained in accordance with applicable law, if any, and these Proxy Procedures. Requested shareholder proposals or other Shareholder Advocacy must be submitted for consideration pursuant to the Shareholder Advocacy Policy and Procedures.

Voting of Proxies - SubAdvisers

In the case of proxies voted by a sub-adviser to a Fund pursuant to the Fund's proxy voting procedures, the Advisers will request the sub-adviser to certify to the Advisers that the sub-adviser has voted the Fund's proxies as required by the Fund's proxy voting policies and procedures and that such proxy votes were executed in a manner consistent with these Proxy Procedures and to provide the Advisers with a report detailing any instances where the sub-adviser voted any proxies in a manner inconsistent with the Fund's proxy voting policies and procedures. The COO of the Advisers will then report to the Board on a quarterly basis regarding the sub-adviser certification and report to the Board any instance where the sub-adviser voted any proxies in a manner inconsistent with the Fund's proxy voting policies and procedures.

The Fund Administration Department maintains procedures affecting all administration functions for the mutual funds. These procedures detail the disclosure and administration of the Trust's proxy voting records.

The Trust's Chief Legal Counsel is responsible for including, in the SAI of each Trust, information about the proxy voting of the Advisers and each sub-adviser.

Reporting to Fund Boards

The CCO of the Advisers will provide the Board with a copy of these Proxy Procedures, accompanied by a certification that represents that the Proxy Procedures have been adopted by the Advisers in conformance with Rule 206(4)-6 under the Advisers Act. Thereafter, the Advisers will provide the Board with notice and a copy of any amendments or revisions to the Procedures and will report quarterly to the Board all material changes to these Proxy Procedures.

The CCO's annual written compliance report to the Board will contain a summary of material changes to the Proxy Procedures during the period covered by the report.

If the Advisers or the Designated Person vote any proxies in a manner inconsistent with either these Proxy Procedures or a Fund's proxy voting policies and procedures, the CCO will provide the Board

with a report detailing such exceptions

Key Contacts

Investment Compliance

Escalation/Reporting Violations

All John Hancock employees are required to report any known or suspected violation of this policy to the CCO of the Funds.

Related Policies and Procedures

N/A

Document Retention Requirements

The Advisers will retain (or arrange for the retention by a third party of) such records relating to proxy voting pursuant to these Proxy Procedures as may be required from time to time by applicable law and regulations, including the following:

1.These Proxy Procedures and all amendments hereto;

2.All proxy statements received regarding Fund portfolio securities;

3.Records of all votes cast on behalf of a Fund;

4.Records of all Fund requests for proxy voting information;

5.Any documents prepared by the Designated Person or a Proxy Voting Committee that were material to or memorialized the basis for a voting decision;

6.All records relating to communications with the Funds regarding Conflicts; and

7.All minutes of meetings of Proxy Voting Committees.

The Office of the CCO, and/or the Legal Department are responsible for maintaining the documents set forth above as needed and deemed appropriate. Such documents will be maintained in the Office of the CCO, and/or the Legal Department for the period set forth in the Records Retention Schedule.

Version History

ANNEX A

The Committee may take into account a wide variety of factors in considering Trustee candidates, including (but not limited to) the criteria set forth below. The Committee may determine that a candidate who does not satisfy these criteria in one or more respects should nevertheless be considered as a nominee if the Committee finds that the criteria satisfied by the candidate and the candidate's other qualifications demonstrate the appropriate level of fitness to serve.

General Criteria

1.Nominees should have a reputation for integrity, honesty and adherence to high ethical standards, and such other personal characteristics as a capacity for leadership and the ability to work well with others.

2.Nominees should have business, professional, academic, financial, accounting or other experience and qualifications which demonstrate that they will make a valuable contribution as Trustees.

3.Nominees should have a commitment to understand the Funds, and the responsibilities of a trustee/director of an investment company and to regularly attend and participate in meetings of the Board and its committees.

4.Nominees should have the ability to understand the sometimes conflicting interests of the various constituencies of the Funds, including shareholders and the investment adviser, and to act in the interests of all shareholders.

5.Nominees should not have, nor appear to have, a conflict of interest that would impair their ability to represent the interests of all the shareholders and to fulfill the responsibilities of a trustee.

6.Nominees should have experience on corporate or other institutional bodies having oversight responsibilities.

It is the intent of the Committee that at least one Independent Trustee be an "audit committee financial expert" as that term is defined in Item 3 of Form N-CSR.

Application of Criteria to Current Trustees

The re-nomination of current Trustees should not be viewed as automatic, but should be based on continuing qualification under the criteria set forth above based on, among other things, the current Trustee's contribution to the Board and any committee on which he or she serves.

Review of Nominations

1.The Committee believes that it is in the best interests of each Trust and its shareholders to obtain highly-qualified candidates to serve as members of the Board.

2.In nominating candidates who would be Independent Trustees, the Committee believes that no particular qualities or skills nor any specific minimum qualifications or disqualifications are controlling or paramount. The Committee shall take into consideration any such factors as it deems appropriate; however, the appropriate mix of skills, expertise and attributes needed to maintain an effective board are sought in the applicant pool as part of every search the Board undertakes for new trustees, including but not limited to the diversity of thought, as well as of gender, race, ethnic background and geographic origin. These factors may also include (but are not limited to) the person's character, integrity, judgment, skill and experience with investment companies and other organizations of comparable purpose, complexity and size and subject to similar legal restrictions and oversight; the interplay of the candidate's experience with the experience of other Board members; and the extent to which the candidate would be a desirable addition to the Board and any Committees thereof. Other factors that the Committee may take into consideration include a person's availability and commitment to attend meetings and perform his or her responsibilities; whether or not the person has or had any relationships that might impair or appear to impair his or her independence, such as any business, financial or family relationships with Fund management, the investment adviser and/or any subadviser of the Funds, as applicable, Fund service providers, or their affiliates or with Fund shareholders. The Committee will strive to achieve a group that reflects a diversity of experiences in respect of industries, professions and other experiences, and that is diversified as to thought, gender, race, ethnic background and geographic origin.

3.While the Committee is solely responsible for the selection and recommendation to the Board of Independent Trustee candidates, the Committee may consider nominees recommended by any source, including shareholders, management, legal counsel and Board members, as it deems appropriate. The Committee may retain a professional search firm or a consultant to assist the Committee in a search for a qualified candidate. Any recommendations from shareholders shall be directed to the Secretary of the relevant Trust at such address as is set forth in the Trust's disclosure documents. Recommendations from management may be submitted to the Committee Chair. All recommendations shall include all information relating to such person that is required to be disclosed in solicitations of proxies for the election of Board members and as specified

in the relevant Trust's By-Laws, and must be accompanied by a written consent of the proposed candidate to stand for election if nominated for the Board and to serve if elected by shareholders.

4.Any shareholder nomination must be submitted in compliance with all of the pertinent provisions of Rule 14a-8 under the Securities Exchange Act of 1934 in order to be considered by the Committee. In evaluating a nominee recommended by a shareholder, the Committee, in addition to the criteria discussed above, may consider the objectives of the shareholder in submitting that nomination and whether such objectives are consistent with the interests of all shareholders. If the Board determines to include a shareholder's candidate among the slate of its designated nominees, the candidate's name will be placed on the Trust's proxy card. If the Board determines not to include such candidate among its designated nominees, and the shareholder has satisfied the requirements of Rule 14a-8, the shareholder's candidate will be treated as a nominee of the shareholder who originally nominated the candidate. In that case, the candidate will not be named on the proxy card distributed with the Trust's proxy statement.

5.As long as a current Independent Trustee continues, in the opinion of the Committee, to satisfy the criteria listed above, the Committee generally would favor the re-nomination of a current Trustee rather than a new candidate. Consequently, while the Committee will consider nominees recommended by shareholders to serve as trustees, the Committee may only act upon such recommendations if there is a vacancy on the Board, or the Committee determines that the selection of a new or additional Trustee is in the best interests of the relevant Trust. In the event that a vacancy arises or a change in Board membership is determined to be advisable, the Committee will, in addition to any shareholder recommendations, consider candidates identified by other means as discussed in this Annex A.

6.With respect to candidates for Independent Trustee, a biography of each candidate shall be acquired and shall be reviewed by counsel to the Independent Trustees and counsel to the Trust to determine the candidate's eligibility to serve as an Independent Trustee.

7.The Committee may from time to time establish specific requirements and/or additional factors to be considered for Independent Trustee candidates as it deems necessary or appropriate.

8.After its consideration of relevant factors, the Committee shall present its recommendation(s) to the full Board for its consideration.

Important information regarding your distributions

We are providing shareholders of the John Hancock Preferred Income Fund III with information concerning the portion of the distributions made for May 31, 2023, that was from a source other than net investment company book income. No action is required on your part.

The amounts and sources of distributions reported in this notice are estimates, are not being provided for tax reporting purposes and may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. The actual amounts and sources for tax reporting purposes will depend upon the Fund's investment experience during the remainder of the fiscal year and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(1)The amounts and sources of distributions reported above are only estimates on a book basis. These estimates may, and likely will, vary over time based on the investment activities of the Fund and changes in the value of portfolio investments. The sources of distributions may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. Investors should understand that a return of capital is not a distribution from income or gains of a Fund.

(2)On a tax basis, the estimated components of the current distribution and cumulative distribution would include an estimated return of capital of $0.0154 (14%) and $0.1538 (14%), respectively. These amounts are estimates and the actual amounts and sources for tax reporting purposes may change upon final determination of tax characteristics and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(3)The Fund's current fiscal year began on August 1, 2022, and will end on July 31, 2023.

If you have questions or need additional information, please contact your financial professional or call the John Hancock Investment Management Closed-End Fund Information Line at 1-800-843- 0090, Monday through Friday between 8:00 a.m. and 7:00 p.m., Eastern Time.

Important information regarding your distributions

We are providing shareholders of the John Hancock Preferred Income Fund III with information concerning the portion of the distributions made for July 31, 2023, that was from a source other than net investment company book income. No action is required on your part.

The amounts and sources of distributions reported in this notice are estimates, are not being provided for tax reporting purposes and may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. The actual amounts and sources for tax reporting purposes will depend upon the Fund's investment experience during the remainder of the fiscal year and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(1)The amounts and sources of distributions reported above are only estimates on a book basis. These estimates may, and likely will, vary over time based on the investment activities of the Fund and changes in the value of portfolio investments. The sources of distributions may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. Investors should understand that a return of capital is not a distribution from income or gains of a Fund.

(2)On a tax basis, the estimated components of the current distribution and cumulative distribution would include an estimated return of capital of $0.0187 (17%) and $0.2241 (17%), respectively. These amounts are estimates and the actual amounts and sources for tax reporting purposes may change upon final determination of tax characteristics and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(3)The Fund's current fiscal year began on August 1, 2022, and will end on July 31, 2023.

If you have questions or need additional information, please contact your financial professional or call the John Hancock Investment Management Closed-End Fund Information Line at 1-800-843- 0090, Monday through Friday between 8:00 a.m. and 7:00 p.m., Eastern Time.

Important information regarding your distributions

We are providing shareholders of the John Hancock Preferred Income Fund III with information concerning the portion of the distributions made for April 28, 2023, that was from a source other than net investment company book income. No action is required on your part.

The amounts and sources of distributions reported in this notice are estimates, are not being provided for tax reporting purposes and may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. The actual amounts and sources for tax reporting purposes will depend upon the Fund's investment experience during the remainder of the fiscal year and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(1)The amounts and sources of distributions reported above are only estimates on a book basis. These estimates may, and likely will, vary over time based on the investment activities of the Fund and changes in the value of portfolio investments. The sources of distributions may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. Investors should understand that a return of capital is not a distribution from income or gains of a Fund.

(2)On a tax basis, the estimated components of the current distribution and cumulative distribution would include an estimated return of capital of $0.0165 (15%) and $0.1483 (15%), respectively. These amounts are estimates and the actual amounts and sources for tax reporting purposes may change upon final determination of tax characteristics and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(3)The Fund's current fiscal year began on August 1, 2022, and will end on July 31, 2023.

If you have questions or need additional information, please contact your financial professional or call the John Hancock Investment Management Closed-End Fund Information Line at 1-800-843- 0090, Monday through Friday between 8:00 a.m. and 7:00 p.m., Eastern Time.

Important information regarding your distributions

We are providing shareholders of the John Hancock Preferred Income Fund III with information concerning the portion of the distributions made for February 28, 2023, that was from a source other than net investment company book income. No action is required on your part.

The amounts and sources of distributions reported in this notice are estimates, are not being provided for tax reporting purposes and may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. The actual amounts and sources for tax reporting purposes will depend upon the Fund's investment experience during the remainder of the fiscal year and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(1)The amounts and sources of distributions reported above are only estimates on a book basis. These estimates may, and likely will, vary over time based on the investment activities of the Fund and changes in the value of portfolio investments. The sources of distributions may later be determined to be from taxable net investment income, short-term gains, long-term gains (to the extent permitted by law), and return of capital. Investors should understand that a return of capital is not a distribution from income or gains of a Fund.

(2)On a tax basis, the estimated components of the current distribution and cumulative distribution would include an estimated return of capital of $0.0110 (10%) and $0.0769 (10%), respectively. These amounts are estimates and the actual amounts and sources for tax reporting purposes may change upon final determination of tax characteristics and may be subject to changes based on tax regulations. The Fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes.

(3)The Fund's current fiscal year began on August 1, 2022, and will end on July 31, 2023.

If you have questions or need additional information, please contact your financial professional or call the John Hancock Investment Management Closed-End Fund Information Line at 1-800-843- 0090, Monday through Friday between 8:00 a.m. and 7:00 p.m., Eastern Time.