MKL Markel Group Inc

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-223194

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 AND ARE NOT A SOLICITATION OF AN OFFER TO BUY THESE SECURITIES IN ANY JURISDICTION WHERE THE OFFER OR SALE IS NOT PERMITTED.

is a function of the total amount of losses incurred, the number of insureds affected, the frequency and severity of the events, the effectiveness of our catastrophe risk management program and the adequacy of our reinsurance coverage. Most catastrophes occur over a small geographic area; however, some catastrophes may produce significant damage in large, heavily populated areas. In addition, catastrophes may have a material adverse effect on the investment management and incentive fees earned by our insurance-linked securities operations and returns on our investments in insurance-linked securities funds. Catastrophes also may result in significant disruptions in our insurance and other operations, as well as loss of income and assets. If climate change results in an increase in the frequency and severity of weather-related catastrophes, we may experience additional catastrophe-related losses or disruptions, which may be material.

Our results may be affected because actual insured or reinsured losses differ from our loss reserves.

Significant periods of time often elapse between the occurrence of an insured or reinsured loss, the reporting of the loss to us and our payment of that loss. To recognize liabilities for unpaid losses, we establish reserves as balance sheet liabilities representing estimates of amounts needed to pay reported and unreported losses and the related loss adjustment expenses. The process of estimating loss reserves is a difficult and complex exercise involving many variables and subjective judgments. This process may become more difficult if we experience a period of rising inflation. As part of the reserving process, we review historical data and consider the impact of such factors as:

This process assumes that past experience, adjusted for the effects of current developments and anticipated trends, is an appropriate basis for predicting future events. There is no precise method, however, for evaluating the impact of any specific factor on the adequacy of reserves, and actual results will differ from original estimates. As part of the reserving process, we regularly review our loss reserves and make adjustments as necessary. Future increases in loss reserves will result in additional charges to earnings, which may be material.

In addition, reinsurance reserves are subject to greater uncertainty than insurance reserves primarily because a reinsurer relies on (i) the original underwriting decisions made by ceding companies and (ii) information and data from ceding companies. As a result, we are subject to the risk that our ceding companies may not have adequately evaluated the risks reinsured by us and the premiums ceded may not adequately compensate us for the risks we assume. In addition, reinsurance reserves may be less reliable than insurance reserves because there is generally a longer lapse of time from the occurrence of the event to the reporting of the loss or benefit to the reinsurer and ultimate resolution or settlement of the loss.

Changes in the assumptions and estimates used in establishing reserves for our life and annuity reinsurance book could result in material increases in our estimated loss reserves for such business.

Our run-off life and annuity reinsurance book exposes us to mortality risk, which is the risk that the level of death claims may differ from that which we assumed in establishing the reserves for our life and annuity reinsurance contracts. Some of our life and annuity reinsurance contracts expose us to longevity risk, which is the risk that an insured person will live longer than expected when the reserves were established, or morbidity risk, which is the risk that an insured person will become critically ill or disabled. Our reserving process for the life and annuity reinsurance book is designed with the objective of establishing appropriate reserves for the risks we

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assumed. Among other things, these processes rely heavily on analysis of mortality, longevity and morbidity trends, lapse rates, interest rates and expenses. As of June 30, 2019, our reserves for life and annuity benefits totaled $1.0 billion.

We expect mortality, morbidity, longevity, and lapse experience to fluctuate somewhat from period to period, but believe they should remain reasonably predictable over a period of many years. Mortality, longevity, morbidity or lapse experience that is less favorable than the mortality, longevity, morbidity or lapse rates that we used in establishing the reserves for a reinsurance agreement will negatively affect our net income because the reserves we originally set for the risks we assumed may not be sufficient to cover the future claims and expense payments. Furthermore, even if the total benefits paid over the life of the contract do not exceed the expected amount, unexpected increases in the incidence of deaths or illness can cause us to pay more benefits in a given reporting period than expected, adversely affecting our net income in any particular reporting period. Fluctuations in interest rates will impact the performance of our investments. If there are changes to any of the above factors to the point where a reserve deficiency exists, a charge to earnings will be recorded, which may have a material adverse effect on our results of operations and financial condition.

Our ability to make payments on debt or other obligations depends on the receipt of funds from our subsidiaries.

We are a holding company, and as a result, our cash flow and our ability to service our debt depend upon the earnings of our subsidiaries and on the distribution of earnings, loans or other payments by our subsidiaries to us. In addition, payment of dividends by our insurance subsidiaries, which account for a significant portion of our operating cash flows, may require prior regulatory notice or approval or may be restricted by capital requirements imposed by regulatory authorities. In addition, our reinsurance contracts typically allow the cedent, upon a reduction in an insurance company’s capital in excess of specified amounts, to terminate its contract on terms disadvantageous to us or to exercise other remedies that may adversely affect us. Those contract provisions may have the effect of limiting distributions by our insurance subsidiaries to us.

Our investment results may be impacted by changes in interest rates, U.S. and international monetary and fiscal policies as well as broader economic conditions.

We receive premiums from customers for insuring their risks. We invest these funds until they are needed to pay policyholder claims or until they are recognized as profits. Fluctuations in the value of our investment portfolio can occur as a result of changes in interest rates and U.S. and international monetary and fiscal policies as well as broader economic conditions (including, for example, equity market conditions and significant inflation or deflation). Our investment results may be materially impacted by one or more of these factors.

Competition in the insurance and reinsurance markets could reduce our underwriting profits.

Insurance and reinsurance markets are highly competitive. We compete on an international and regional basis with major U.S., Bermuda, European, and other international insurers and reinsurers and with underwriting syndicates, some of which have greater financial, marketing, and management resources than we do. Recent industry consolidation, including business combinations among insurance and other financial services companies, has resulted in larger competitors with even greater financial resources. We also compete with new companies that continue to be formed to enter the insurance and reinsurance markets, particularly companies with new or “disruptive” technologies or business models. In addition, capital market participants have created alternative products that are intended to compete with reinsurance products. Increased competition could result in fewer submissions, lower premium rates, and less favorable policy terms and conditions, which could reduce our underwriting profits and have a material adverse effect on our results of operations and financial condition.

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The historical cyclicality in the property and casualty insurance industry could have a material adverse effect on our ability to improve or maintain underwriting profits or to grow or maintain premium volume.

The insurance and reinsurance markets have historically been cyclical, characterized by extended periods of intense price competition due to excessive underwriting capacity as well as brief periods when shortages of capacity permitted more favorable rate levels. Among our competitive strengths have been our specialty product focus and our niche market strategy. These strengths also make us vulnerable in periods of intense competition to actions by other insurance companies who seek to write additional premiums without appropriate regard for underwriting profitability. During soft markets, it could be very difficult for us to grow or maintain premium volume levels without sacrificing underwriting profits. If we are not successful in maintaining rates or achieving rate increases, it may be difficult for us to improve or maintain underwriting profits or to grow or maintain premium volume levels.

We invest a significant portion of our invested assets in equity securities, which may result in significant variability in our investment results and net income and may have a material adverse effect on shareholders’ equity. Additionally, our equity investment portfolio is concentrated, and declines in the value of these significant investments could have a material adverse effect on our financial results.

Equity securities were 66% of our shareholders’ equity at June 30, 2019 and 63% at December 31, 2018. Equity securities have historically produced higher returns than fixed maturities over long periods of time; however, investing in equity securities may result in significant variability in investment returns from one period to the next. In volatile financial markets, we could experience significant declines in the fair value of our equity investment portfolio, which would result in a material decrease in net income and shareholders’ equity. Our equity portfolio is concentrated in particular issuers and industries and, as a result, a decline in the fair value of these concentrated investments also could result in a material decrease in net income and shareholders’ equity. A material decrease in shareholders’ equity may have a material adverse effect on our ability to carry out our business plans.

General economic, market or industry conditions could lead to investment losses, adverse effects on our businesses and limit our access to the capital markets.

General economic and market conditions and industry specific conditions, including extended economic recessions or expansions; prolonged periods of slow economic growth; inflation or deflation; fluctuations and volatility in foreign currency exchange rates, commodity and energy prices and interest rates; volatility in the credit and capital markets; and other factors, could lead to substantial realized and unrealized investment losses in future periods, declines in demand for or increased claims made under our insurance products or limited or no access to the capital markets, any of which could have a material adverse effect on our results of operations, financial condition, debt and financial strength ratings or our insurance subsidiaries’ capital.

We rely on the purchase of reinsurance and bear collection risk if the reinsurer fails to meet its obligations under the reinsurance agreement.

Our underwriting operations purchase reinsurance and retrocessional reinsurance to manage our net retention on individual risks and overall exposure to losses, while providing us with the ability to offer policies with sufficient limits to meet policyholder needs. Our program services business reinsures substantially all of its underwriting and operating risks in connection with its fronting arrangements.

The ceding of insurance does not legally discharge us from our primary liability for the full amount of the policies. Reliance on reinsurance may create credit risk as a result of the reinsurer’s inability or unwillingness to pay reinsurance claims when due. We generally select well capitalized and highly rated reinsurers and in certain instances we require reinsurers to post substantial collateral to secure the reinsured risks. Deterioration in the

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credit quality of existing reinsurers or disputes over the terms of reinsurance could result in charges to earnings, which may have a material adverse effect on our results of operations and financial condition. In addition, collateral may not be sufficient to cover our liability, and we may not be able to cause the reinsurer to deliver additional collateral.

As of December 31, 2018, we were the beneficiary of letters of credit, trust accounts and funds withheld in the aggregate amount of $3.2 billion, collateralizing $5.2 billion in reinsurance recoverables. The remaining unsecured reinsurance recoverables are ceded to highly-rated, well capitalized reinsurers. Our reinsurance recoverables are based on estimates, and our actual liabilities may exceed the amount we are able to recover from our reinsurers or any collateral securing the liabilities. The failure of a reinsurer to meet its obligations to us, whether due to insolvency, dispute or other unwillingness or inability to pay, or due to our inability to access sufficient collateral to cover our liabilities, could have a material adverse effect on our results of operations and financial condition.

The availability and cost of reinsurance are determined by market conditions beyond our control. There is no guarantee that our desired amounts of reinsurance or retrocessional reinsurance will be available in the marketplace in the future.

Our insurance subsidiaries are subject to extensive supervision and regulation that may have a material adverse effect on our ability to implement and achieve our business objectives.

Our insurance subsidiaries are subject to extensive supervision and regulation by the regulatory authorities in the various jurisdictions in which they conduct business, including state, national and international insurance regulators. This supervision and regulation is intended for the benefit of policyholders rather than shareholders or holders of debt securities. Regulatory authorities have broad regulatory, supervisory and administrative powers relating to, among other things, data protection and data privacy, solvency standards, licensing, coverage requirements, policy rates and forms and the form and content of financial reports. Regulatory and legislative authorities continue to implement enhanced or new regulatory requirements intended to prevent future financial crises or otherwise assure the stability of financial institutions. Regulatory authorities also may seek to exercise their supervisory or enforcement authority in new or more extensive ways, such as imposing increased capital requirements. These actions, if they occur, could affect the competitive market and the way we conduct our business and manage our capital and could result in lower revenues and higher costs. As a result, such actions could have a material adverse effect on our results of operations and financial condition.

The legal and regulatory requirements applicable to our businesses are extensive. Failure to comply could have a material adverse effect on us.

Each of our businesses is highly dependent on the ability to engage on a daily basis in a large number of financial and operational activities, including among others insurance underwriting, claim processing, investment activities, the management of third party capital and providing products and services to businesses and consumers, many of which are highly complex. These activities are subject to internal guidelines and policies, as well as legal and regulatory standards, including, among others, those related to privacy, anti-corruption, anti-bribery and global finance and investments and insurance matters. Our continued expansion into new businesses and markets has brought about additional requirements. While we believe that we have adopted appropriate risk management and compliance programs, compliance risks will continue to exist, particularly as we become subject to new rules and regulations. Failure to comply with, or to obtain, appropriate authorizations or exemptions under any applicable laws and regulations could result in restrictions on our ability to do business or undertake activities that are regulated in one or more of the jurisdictions in which we conduct business. Any such failure could also subject us to fines, penalties, equitable relief and changes to our business practices. In addition, a failure to comply could result in defaults under our senior unsecured debt agreements (including the notes) or credit facilities or damage our businesses or our reputation. Compliance with applicable laws and regulations is time consuming and personnel-intensive, and changes in these laws and regulations could materially increase our

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direct and indirect compliance costs and other expenses of doing business, and have a material adverse effect on our results of operations and financial condition.

The amount of capital that our insurance subsidiaries have and must hold to maintain their financial strength and credit ratings and meet other requirements can vary significantly from time to time and is sensitive to a number of factors outside of our control.

Capital requirements for our insurance subsidiaries are prescribed by the applicable insurance regulators and the National Association of Insurance Commissioners (NAIC), while rating agencies establish requirements that inform ratings for our insurance subsidiaries and senior debt securities. Projecting surplus and the related capital requirements is complex and requires making assumptions regarding how our business will perform within the broader macroeconomic environment. Insurance regulators and rating agencies evaluate company capital through financial models that calculate minimum capitalization requirements based on risk-based capital formulas for property and casualty insurance groups and their subsidiaries. In any particular year, capital levels and risk-based capital requirements may increase or decrease depending on a variety of factors including the amount of income or losses generated by our insurance subsidiaries, the amount of additional capital our insurance subsidiaries must hold to support business growth, the value of certain fixed maturities and equity securities in our investment portfolio, changes in interest rates and foreign currency exchange rates, as well as changes to the regulatory and rating agency models used to determine our required capital. In addition, the NAIC is developing a group capital calculation for U.S. based global insurance groups, and expects to implement a new standard in 2020. Even though it is not intended to be a prescribed capital requirement, this calculation could have an impact on the amount of group capital we are required to hold and how it is allocated.

Information technology systems that we use could fail or suffer a security breach, which could have a material adverse effect on us or result in the loss of sensitive information.

Our businesses are dependent upon the operational effectiveness and security of our enterprise systems and those maintained by third parties. Among other things, we rely on these systems to interact with producers, insureds, customers, clients, and other third parties, to perform actuarial and other modeling functions, to underwrite business, to prepare policies and process premiums, to process claims and make claims payments, to prepare internal and external financial statements and information, as well as to engage in a wide variety of other business activities. A significant failure of our enterprise systems, or those of third parties upon which we may rely, whether because of a natural disaster, network outage or a cyber-attack on our systems, could compromise our personal, confidential and proprietary information as well as that of our customers and business partners, impede or interrupt our business operations and could result in other negative consequences, including remediation costs, loss of revenue, additional regulatory scrutiny and fines, litigation and monetary and reputational damages. Although we have implemented controls and take protective actions to reduce the risk of an enterprise failure and protect against a security breach, such measures may be insufficient to prevent, or mitigate the effects of, a natural disaster, network outage or a cyber-attack on our systems that could result in liability to us, cause our data to be corrupted or stolen and cause us to commit resources, management time and money to prevent or correct those failures.

In addition, we are subject to numerous data privacy laws and regulations enacted in the jurisdictions in which we do business. A misuse or mishandling of confidential or proprietary information being sent to or received from a client, employee or third party could damage our businesses or our reputation or result in significant monetary damages, regulatory enforcement actions, fines and criminal prosecution in one or more jurisdictions. For example, under the European General Data Protection Regulation there are significant new punishments for non-compliance which could result in a penalty of up to 4% of a firm’s global annual revenue. In addition, a violation of data privacy laws and regulations could result in defaults under our outstanding indebtedness or credit facilities. Those monetary damages, penalties, regulatory or legal actions or defaults, or the damage to our businesses or reputation, could have a material adverse effect on our results of operations and financial condition. Third parties to whom we outsource certain functions are also subject to these risks, and their

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failure to adhere to these laws and regulations also could damage our businesses or reputation, could have a material adverse effect on our results of operations and financial condition.

Further, we routinely transmit, receive and store personal, confidential and proprietary information by email and other electronic means. Although we attempt to protect this confidential and proprietary information, we may be unable to do so in all cases, especially with customers, business partners and other third parties who may not have or use appropriate controls to protect confidential information.

While we maintain cyber risk insurance providing first party and third party coverages, such insurance may not cover all costs associated with the consequences of personal and confidential and proprietary information being compromised. A material cyber security breach could have a material adverse effect on our results of operations and financial condition.

We may not find suitable acquisition candidates or new ventures.

As part of our growth strategy, we continue to evaluate possible acquisition transactions on an ongoing basis, and at any given time we may be engaged in discussions with respect to possible acquisitions and new ventures. We may not be able to identify suitable acquisition targets or ventures, any such transactions may not be financed or completed on acceptable terms and our future acquisitions or ventures may not be successful.

The integration of acquired companies may not be as successful as we anticipate.

We have recently engaged in a number of acquisitions in an effort to achieve profitable growth in our underwriting operations and to create additional value on a diversified basis in our Markel Ventures and other operations. Acquisitions present operational, strategic and financial risks, as well as risks associated with liabilities arising from the previous operations of the acquired companies. All of these risks are magnified in the case of a large acquisition. Assimilation of the operations and personnel of acquired companies may prove more difficult than anticipated, which may result in failure to achieve financial objectives associated with the acquisition or diversion of management attention. In addition, integration of formerly privately-held companies into the management and internal control and financial reporting systems of a publicly-held company presents additional risks.

Impairment in the value of our goodwill or other intangible assets could have a material adverse effect on our operating results and financial condition.

As of June 30, 2019, goodwill and intangible assets totaled $3.9 billion and represented 37% of shareholders’ equity. We record goodwill and intangible assets at fair value upon the acquisition of a business. Goodwill represents the excess of amounts paid for acquiring businesses over the fair value of the net assets acquired. Goodwill and indefinite-lived intangible assets are evaluated for impairment annually, or more frequently if conditions warrant, by comparing the carrying value of a reporting unit to its estimated fair value for goodwill and by comparing the carrying value of the asset to its fair value for indefinite-lived intangible assets. Intangible assets with definite lives are reviewed for impairment when events or circumstances indicate that their carrying value may not be recoverable. Declines in operating results, divestitures, sustained market declines and other factors that impact the fair value of a reporting unit could result in an impairment of goodwill or intangible assets and, in turn, a charge to net income. Such a charge could have a material adverse effect on our results of operations or financial condition.

For example, in 2018 and 2017 we recorded $1.1 billion and $1.3 billion, respectively, of goodwill and intangible assets in connection with the acquisitions of Nephila and Brahmin in 2018 and SureTec, Costa Farms and State National in 2017. Developments that adversely affect the future cash flows or earnings of an acquired business may cause the goodwill or intangible assets recorded for it to be impaired. For example, in 2018 we reduced the carrying value of the goodwill and intangible assets of the MCIM reporting unit, acquired in 2015, to zero, which resulted in a combined goodwill and intangible assets impairment charge of $179.0 million.

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The failure of any of the loss limitation methods we employ could have a material adverse effect on us.

We seek to limit our loss exposure in a variety of ways, including adhering to maximum limitations on policies written in defined geographical zones, limiting program size for each client, establishing per risk and per occurrence limitations for each event, employing coverage restrictions and following prudent underwriting guidelines for each program written. We also seek to limit our loss exposure through geographic diversification. Underwriting is a matter of judgment, involving assumptions about matters that are inherently unpredictable and beyond our control, and for which historical experience and probability analysis may not provide sufficient guidance. One or more future events could result in claims that substantially exceed our expectations, which could have a material adverse effect on our financial condition and our results of operations, possibly to the extent of eroding away our shareholders’ equity. In addition, we seek to limit loss exposures by policy terms, exclusion from coverage and choice of legal forum. Disputes relating to coverage and choice of legal forum also arise. As a result, various provisions of our policies, such as choice of forum, limitations or exclusions from coverage may not be enforceable in the manner we intend and some or all of our loss limitation methods may prove ineffective.

The effects of emerging claim and coverage issues on our business are uncertain.

As industry practices and legal, judicial, social and other environmental conditions change, unexpected and unintended issues related to claims and coverage may emerge. These issues may have a material adverse effect on our business by either broadening coverage beyond our underwriting intent or by increasing the number or size of claims. In some instances, these changes may not become apparent until after we have issued insurance or reinsurance contracts that are affected by the changes. As a result, the full extent of liability under our insurance or reinsurance contracts may not be known for many years after a contract is issued. For example, many states have recently extended the statute of limitations for certain victims of sexual abuse. This may result in a higher frequency of claims over a more extended reporting period than originally expected.

The loss of one or more key executives or an inability to attract and retain qualified personnel could have a material adverse effect on us.

Our success depends on our ability to retain the services of our existing key executives and to attract and retain additional qualified personnel in the future. The loss of the services of any of our key executives or the inability to hire and retain other highly qualified personnel in the future could have a material adverse effect on our ability to conduct or grow our business.

We have substantial international operations and investments, which expose us to increased political, operational and economic risks.

A substantial portion of our revenues and income is derived from our operations and investments outside the U.S., including from the U.K., Bermuda, Europe, Canada, Latin America, Asia Pacific and the Middle East. Our international operations and investments expose us to increased political, operational and economic risks. Deterioration or volatility in foreign and international financial markets or general economic and political conditions could adversely affect our operating results, financial condition and liquidity. Concerns about the economic conditions, capital markets, political and economic stability and solvency of certain countries have contributed to global market volatility. Political changes in the jurisdictions where we operate and elsewhere, some of which may be disruptive, can also interfere with our customers and our activities in a particular location. Our international operations also may be subject to a number of additional risks, particularly in emerging economies, including restrictions such as price controls, capital controls, currency exchange limits, ownership limits and other restrictive or anti-competitive governmental actions or requirements, which could have a material adverse effect on our businesses.

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Changes in regulations and interpretations relating to the Tax Cuts and Jobs Act could have a material adverse effect on us.

On December 22, 2017, the U.S. enacted the Tax Cuts and Jobs Act (TCJA), which made significant modifications to U.S. federal income tax law, most of which were effective January 1, 2018. The U.S. Treasury Department and the Internal Revenue Service continue to issue guidance and interpretations of how provisions of the TCJA will be applied or otherwise administered. Changes in regulations and interpretations relating to the TCJA could have a material adverse effect on our results of operation and financial condition.

Our insurance companies and senior debt are rated by various rating agencies, and a downgrade or potential downgrade in one or more of these ratings could have a material adverse effect on us.

Financial strength ratings are an important factor in establishing the competitive position of insurance and reinsurance companies. Our senior debt ratings also affect the availability and cost of capital. Certain of our insurance and reinsurance company subsidiaries and our senior debt securities are rated by various rating agencies. Our financial strength and debt ratings are subject to periodic review, and are subject to revision or withdrawal at any time. The financial strength ratings of our insurance subsidiaries are significantly influenced by their statutory surplus amounts and leverage and capital adequacy ratios and other financial metrics. Rating agencies may implement changes to their ratings methodologies or internal models that have the effect of increasing or decreasing the amount of capital our insurance subsidiaries must hold or restrict how the company may deploy its capital in order to maintain its current ratings. For example, for certain of our insurance subsidiaries, rating agencies may take into account in their calculations the collateral provided to us by reinsurers. A change in this practice could adversely impact our ratings. We cannot be sure that we will be able to retain our current or any future ratings. If our ratings are reduced from their current levels by one or more rating agencies, our competitive position in our target markets within the insurance industry could suffer and it would be more difficult for us to market our products. A ratings downgrade could result in a substantial loss of business as policyholders and ceding company clients move to other companies with higher claims-paying and financial strength ratings. In addition a downgrade could trigger contract provisions that allow cedents to terminate their reinsurance contracts on terms disadvantageous to us or require us to collateralize our obligations through trusts or letters of credit. A ratings downgrade could also have a material adverse effect on our liquidity, including the availability of our letter of credit facilities, and limit our access to capital markets, increase our cost of borrowing or issuing debt and require us to post collateral.

We may require additional capital in the future, which may not be available or may only be available on unfavorable terms.

To the extent that cash flows generated by our operations are insufficient to fund future operating requirements, or that our capital position is adversely impacted by a decline in the fair value of our investment portfolio, losses from catastrophe events or otherwise, we may need to raise additional funds through financings or curtail our growth. We also may be required to liquidate fixed maturities or equity securities, which may result in realized investment losses. Any further sources of liquidity, including capacity needed for letters of credit, if available at all, may be on terms that are unfavorable to us. Our access to additional sources of liquidity will depend on a variety of factors, such as market conditions, the general availability of credit, the availability of credit to the industries in which we operate, our results of operations, financial condition, credit ratings and credit capacity, as well as pending litigation or regulatory investigations. Our ability to borrow under our revolving credit facility and letter of credit facilities is contingent on our compliance with the covenants and other requirements under those facilities. Similarly, our access to capital may be impaired if regulatory authorities or rating agencies take negative actions against us. Our inability to obtain adequate capital when needed could have a negative impact on our ability to invest in, or take advantage of opportunities to expand, our businesses, such as possible acquisitions or the creation of new ventures, and inhibit our ability to refinance our existing indebtedness on terms acceptable to us. Any of these effects could have a material adverse effect on our results of operations and financial condition.

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Our failure to comply with covenants and other requirements under our revolving credit facility, senior debt and other indebtedness could have a material adverse effect on us.

The agreements and indentures relating to our revolving credit facility, senior debt (including the notes) and other indebtedness, including letter of credit facilities used by certain of our insurance subsidiaries, contain covenants and other requirements. If we fail to comply with those covenants or requirements, the lenders, noteholders or counterparties under those agreements and indentures could declare a default and demand immediate repayment of all amounts owed to them. In addition, where applicable, our lenders may cancel their commitments to lend or issue letters of credit or require us to pledge additional or a different type of collateral. A default under one debt agreement may also put us at risk of a cross-default under other debt agreements or other arrangements. Any of these effects could have a material adverse effect on our results of operations and financial condition.

We depend on a few brokers for a large portion of our revenues and the loss of business provided by any one of them could have a material adverse effect on us.

We market our insurance and reinsurance worldwide through insurance and reinsurance brokers. For the year ended December 31, 2018, our top three independent brokers represented 25% of the gross premiums written by our underwriting operations. Loss of all or a substantial portion of the business provided by one or more of these brokers could have a material adverse effect on our business.

Employee error and misconduct may be difficult to detect and prevent and may result in significant losses.

There have been a number of cases involving misconduct by employees in a broad range of industries in recent years, and we run the risk of misconduct by our employees. Instances of fraud, illegal acts, errors, failure to document transactions properly or to obtain proper internal authorization, or failure to comply with regulatory requirements or our internal policies may result in losses. It is not always possible to deter or prevent employee errors or misconduct, and the controls that we have in place to prevent and detect this activity may not be effective in all cases.

We are subject to laws and regulations relating to economic and trade sanctions and bribery and corruption, the violation of which could have a material adverse effect on us.

We are required to comply with the economic and trade sanctions and embargo programs administered by the United States Department of the Treasury’s Office of Foreign Assets Control and similar multi-national bodies and governmental agencies worldwide, as well as applicable anti-corruption laws and anti-bribery and regulations of the United States, the United Kingdom and other jurisdictions where we operate. A violation of a sanction, embargo program, or anti-corruption law, could subject us, and individual employees, to a regulatory enforcement action as well as significant civil and criminal penalties. In addition, a violation could result in defaults under our outstanding indebtedness or credit facilities or damage our businesses or our reputation. Those penalties or defaults, or damage to our businesses or reputation, could have a material adverse effect on our results of operations and financial condition. In some cases the requirements and limitations applicable to the global operations of U.S. companies and their affiliates are more restrictive than, and may even conflict with, those applicable to non-U.S. companies and their affiliates, which also could have a material adverse effect on our results of operations and financial condition.

Losses from legal and regulatory actions may have a material adverse effect on us.

We are involved in various legal actions, including at times multi-party or class action litigation, some of which involve claims for substantial or indeterminate amounts. We are also involved from time to time in various regulatory actions, investigations and inquiries, including market conduct exams by insurance regulatory authorities. An unfavorable outcome in one or more of these matters could have a material adverse effect on our

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results of operations and financial condition. If any regulatory authority takes action against us or we enter into an agreement to settle a matter, we may incur sanctions or be required to pay substantial fines or implement remedial measures that could prove costly or disruptive to our businesses and operations. Even if an unfavorable outcome does not materialize, these matters could have an adverse impact on our reputation and result in substantial expense and disruption.

Regulators may challenge our use of fronting arrangements in states in which our capacity providers are not licensed.

Our program services business enters into fronting arrangements with general agents and domestic and foreign insurers that want to access specific U.S. property and casualty insurance business in states in which the capacity providers are not licensed or are not authorized to write particular lines of insurance. Some state insurance regulators may object to these fronting arrangements. In certain states, an insurance commissioner has the authority to prohibit an authorized insurer from acting as an issuing carrier for an unauthorized insurer. In addition, insurance departments in states in which there is no such statutory or regulatory prohibition, could deem the assuming insurer to be transacting insurance business without a license and the issuing carrier to be aiding and abetting the unauthorized sale of insurance.

If regulators in any of the states where we conduct our fronting business were to prohibit or limit those arrangements, we would be prevented or limited from conducting that business for which a capacity provider is not authorized in those states, unless and until the capacity provider is able to obtain the necessary licenses. This could have a material adverse effect on our results of operations and financial condition.

We may be exposed to risk in connection with our management of third party capital.

Some of our operating subsidiaries may owe certain legal duties and obligations to third party investors. A failure to fulfill any such duties or obligations could result in significant liabilities, penalties or other losses, and harm our businesses and results of operations. In addition, third party investors may decide not to renew their interests in the funds we manage, which could materially impact the financial condition of those funds, and could, in turn, have a material adverse effect on our results of operations and financial condition. Moreover, we may not be able to maintain or raise additional third party capital for the funds we manage or for potential new funds and therefore we may forego existing or potential fee income and other income generating opportunities. For example, catastrophe losses in 2017 and 2018 may materially adversely impact our ability to maintain or raise capital at our insurance-linked securities operations.

Recent developments at our Markel CATCo operations could have a material adverse effect on us.

The U.S. Department of Justice, U.S. Securities and Exchange Commission and Bermuda Monetary Authority are conducting inquiries into loss reserves recorded in late 2017 and early 2018 at Markel CATCo Re (the Markel CATCo Inquiries). Subsequently, several related putative class actions were filed against Markel Corporation and certain present or former officers and directors alleging violations of the federal securities laws relating to the matters that are the subject of the Markel CATCo Inquiries (the Securities Litigation). The actions were consolidated. On August 6, 2019, the Securities Litigation was voluntarily dismissed. In addition, as a result of matters uncovered in an internal review initiated in response to the Markel CATCo Inquiries, two senior MCIM executives are no longer with MCIM (the MCIM Executive Departures). The performance of MCIM depended heavily on the financial and managerial experience of those two senior executives. Following their departure, the two senior MCIM executives each filed suit against MCIM and Markel Corporation (the MCIM Executive Suits). In June 2019, (1) one of the suits was settled by mutual agreement to the satisfaction of all parties and (2) MCIM, Markel Corporation and the former MCIM executive party to the other suit agreed to commence binding arbitration to finally, fully and confidentially resolve the claims and counterclaims alleged in the action, and that suit was dismissed with prejudice in July 2019. See “Legal Proceedings” in our 2019 Second Quarter Quarterly Report on Form 10-Q for more information regarding the Markel CATCo Inquiries, Securities

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Litigation and MCIM Executive Suits. Further, investors in the Markel CATCo Funds were offered an additional opportunity to have some or all of their respective investments in the Markel CATCo Funds redeemed (the Special Redemption). Through both the Special Redemption and the annual redemption for January 1, 2019, substantially all of the capital in the Markel CATCo Funds was tendered for redemption. In July 2019, MCIM announced that it would cease accepting new investments in the Markel CATCo Funds and would not write any new business in Markel CATCo Re. Both the Markel CATCo Funds and Markel CATCo Re will be placed into run-off, returning capital to investors as it becomes available. The process is expected to take approximately three years.

The Markel CATCo Inquiries, Securities Litigation, MCIM Executive Departures and MCIM Executive Suits, as well as other related matters of which we are currently unaware, could result in additional claims, litigation, investigations, enforcement actions or proceedings. For example, additional litigation may be filed by investors in the Markel CATCo Funds. We also could become subject to increased regulatory scrutiny, investigations or proceedings in any of the jurisdictions where we operate. If any regulatory authority takes action against us or we enter into an agreement to settle a matter, we may incur sanctions or be required to pay substantial fines or implement remedial measures that could prove costly or disruptive to our businesses and operations.

An unfavorable outcome in one or more of these matters, and others we cannot anticipate, could have a material adverse effect on our results of operations and financial condition. In addition, we may take further steps to mitigate potential risks or liabilities that may arise from the Markel CATCo Inquiries and related developments, and some of those steps may have a material impact on our results of operations or financial condition. Even if an unfavorable outcome does not materialize, these matters, and actions we may take in response, could have an adverse impact on our reputation and result in substantial expense and disruption.

The exit of the United Kingdom from the European Union could have a material adverse effect on us.

On June 23, 2016, the U.K. voted to exit the European Union (E.U.) (Brexit), which was originally set to occur on March 29, 2019. The effects of Brexit will depend in part on agreements, if any, the U.K. makes to retain access to E.U. markets. For over two years the U.K. and E.U. have been negotiating the future terms of the U.K.’s relationship with the E.U., including the terms of trade between the U.K. and the E.U. On April 10, 2019, the E.U. granted the U.K. an extension until October 31, 2019 to allow the U.K. to ratify a proposed agreement between the E.U. and the U.K. for the orderly exit of the U.K. from the E.U. The extension will end as soon as an agreement is ratified, if that happens before October 31, 2019. All Brexit terms must be ratified by the U.K. Parliament and the legislative bodies of the 27 E.U. member states.

Brexit could impair or end the ability of both Markel International Insurance Company Limited (MIICL) and our Lloyd’s syndicate to transact business in E.U. countries from our U.K. offices and MIICL’s ability to maintain its current branches in E.U. member states. In order to continue transacting E.U. business if U.K. access to E.U. markets ceases or is materially impaired, we have established a regulated insurance carrier, Markel Insurance SE (MISE), in Munich, Germany. From its offices in Germany, MISE can transact business in all remaining E.U. member states and throughout the European Economic Area (EEA). MISE has established branches in Ireland, the Netherlands, Spain, and the U.K. In addition, the Society of Lloyd’s has organized a new insurance company in Brussels, Belgium, in order to maintain access to E.U. business for Lloyd’s syndicates. We expect that the new Lloyd’s Brussels insurance company will supplement, or serve as an alternative to, MISE for access to E.U. markets.

Without a Brexit agreement, U.K. based insurers may be prohibited from administering policies for, or paying claims to, EEA policyholders post Brexit. In order to provide certainty for its EEA policyholders, MIICL transferred its legacy EEA exposures, claims and policies to MISE. This transfer was approved by the U.K. High Court and became effective on March 29, 2019. Lloyd’s also has commenced its transfer of legacy EEA exposures. However, that transfer is not expected to be completed prior to October 31, 2019, and there is no assurance that approval of that transfer will be granted or on what terms and conditions. Lloyd’s has indicated

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that it intends to honor contractual commitments, including the payment of valid claims, and expects that its approach will be respected by EEA regulators pending the completion of its transfer of legacy EEA exposures. The European Insurance and Occupational Pensions Authority has issued its recommendation to E.U. member states that they adopt legislation to permit the orderly run-off of legacy EEA exposures, claims and policies by U.K. insurers. While some E.U. member states have adopted such legislation, no E.U. member state is obligated to do so, and the terms of any such legislation may vary significantly among the E.U. member states. Without an orderly run-off regime for legacy business in every E.U. member state, Lloyd’s, and in turn, our Lloyd’s syndicate, may be impaired in running-off business, including paying claims, in the E.U. member states.

The U.K.’s exit from the E.U., and negotiations leading up to that exit, could continue to contribute to instability in global financial markets, including foreign currency markets, and adversely affect European and worldwide economic or market conditions. Significant uncertainties remain related to the political, monetary and economic impacts of Brexit, including related tax, accounting and financial reporting implications. Brexit could also lead to legal and regulatory uncertainty and potentially a large number of new and divergent national laws and regulations, including new tax rules, as the U.K. determines which E.U. laws to replace or replicate. These impacts, combined with the legal and regulatory uncertainty, may adversely affect our operations and also may result in increased claims arising from the impact on our policyholders. For example, in the absence of a Brexit agreement or a waiver for cross border data transfers, many U.K. and E.U. companies, including our U.K. and E.U. based operations, may not be able to comply with E.U. data privacy laws immediately upon the Brexit effective date.

Any of these effects of Brexit, and others we cannot anticipate, could have a material adverse effect on our results of operations and financial condition.

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PROSPECTUS

MARKEL CORPORATION

Common Shares, Preferred Shares, Debt Securities, Warrants,

Share Purchase Contracts and Share Purchase Units

From time to time, we may offer and sell:

We will file prospectus supplements and may provide other offering materials that furnish specific terms of the securities to be offered under this prospectus. The terms of the securities will include the initial offering price, aggregate amount of the offering, listing on any securities exchange or quotation system, investment considerations and the agents, dealers or underwriters, if any, to be used in connection with the sale of the securities. You should read this prospectus and any supplement or other offering materials carefully before you invest.

Our common shares are traded on the New York Stock Exchange under the symbol “MKL.”

Investing in our securities involves risks. For a description of these risks, see “Risk Factors” on page 2 of this prospectus and the Risk Factors section of our most recent Annual Report on Form 10-K and in our other reports we file with the Securities and Exchange Commission.

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

The date of this prospectus is February 23, 2018.

MARKEL CORPORATION

General

We are a diverse financial holding company serving a variety of niche markets. Our principal business markets and underwrites specialty insurance products. We believe that our specialty product focus and niche market strategy enable us to develop expertise and specialized market knowledge. We seek to differentiate ourselves from competitors by our expertise, service, continuity and other value-based considerations. We also own interests in various businesses that operate outside of the specialty insurance marketplace. Our financial goals are to earn consistent underwriting and operating profits and superior investment returns to build shareholder value.

We are a Virginia corporation headquartered at 4521 Highwoods Parkway, Glen Allen, Virginia 23060-6148, telephone number (804) 747-0136. We use the terms “we,” “us,” “our,” and “Markel” to refer to Markel Corporation in this prospectus.

Safe Harbor and Cautionary Statements

This prospectus contains or incorporates by reference statements concerning or incorporating our expectations, assumptions, plans, objectives, future financial or operating performance and other statements that are not historical facts. These statements are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements may use words such as “anticipate,” “believe,” “estimate,” “expect,” “intend,” “predict,” “project” and similar expressions as they relate to us or our management. There are risks and uncertainties that may cause actual results to differ materially from predicted results in forward-looking statements. Factors that may cause actual results to differ are often presented with the forward-looking statements themselves. Additional factors that could cause actual results to differ from those predicted will be discussed in our reports on Forms 10-K, 10-Q and 8-K incorporated by reference herein and in prospectus supplements and other offering materials.

By making forward-looking statements, we do not intend to become obligated to publicly update or revise any such statements whether as a result of new information, future events or other changes. You should not place undue reliance on any forward-looking statements, which speak only as at their dates.

Common Shares

Our common shares are listed on the New York Stock Exchange under the symbol “MKL.”

Each holder of our common shares is entitled to one vote for each share held of record on each matter submitted to a vote of shareholders. Cumulative voting in the election of directors is not permitted. As a result, the holders of more than 50% of the outstanding shares have the power to elect all directors. The quorum required at a shareholders’ meeting for consideration of any matter is a majority of the shares entitled to vote on that matter, represented in person or by proxy. If a quorum is present, the affirmative vote of a majority of the shares voting on the matter at the meeting is required for shareholder approval. However, approval is required by the affirmative vote of more than two-thirds of all shares entitled to vote, whether or not represented at the meeting, in the case of major corporate actions, such as:

These provisions, together with our ability to issue preferred shares with disproportionately high voting power could be used in, or have the effect of, preventing or deterring a party from gaining control of Markel, whether or not beneficial to public shareholders, and could discourage tactics that involve an actual or threatened change of control of Markel.

Subject to the rights of any holders of our preferred shares, the holders of common shares are entitled to receive dividends when, as, and if declared by the board of directors out of funds legally available for that purpose and, in the event of liquidation, dissolution or winding up of Markel, to share ratably in all assets remaining after the payment of liabilities. There are no preemptive or other subscription rights, conversion rights, or redemption or sinking fund provisions with respect to common shares. All common shares outstanding upon the consummation of any offering will be legally issued, fully paid and nonassessable.

Our transfer agent and registrar for common shares is American Stock Transfer & Trust Co., LLC.

Voting Rights with Respect to Extraordinary Corporate Transactions

Under Virginia law, a corporation may sell, lease, exchange or otherwise dispose of all, or substantially all, of its property, other than in the usual and regular course of business, if the proposed transaction is approved by more than two-thirds of all of the votes entitled to be cast on that matter. A merger or share exchange plan must be approved by each voting group entitled to vote separately on the plan by more than two-thirds of all the votes entitled to be cast on the plan by that voting group. The articles of incorporation may provide for a greater or lesser vote, but not less than a majority of all the votes cast on the transaction by each voting group entitled to vote on the transaction. Our articles of incorporation do not provide for a greater or lesser vote.

Anti-takeover Statutes

Virginia law, except as to companies that elect not to be covered, prohibits the following business combinations between a Virginia corporation and any “interested shareholder”:

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An interested shareholder of a corporation is, among others, a person who is, or an affiliate or associate of the corporation who was within three years of the transaction, a beneficial owner of more than 10% of any class of the outstanding voting shares of the corporation unless a majority of disinterested directors approved the acquisition of shares making a person an interested shareholder. Unless the affiliated transaction comes within an applicable exemption, an affiliated transaction in the three years after a person becomes an interested shareholder must be approved by the affirmative vote of a majority of the disinterested directors and by the affirmative vote of the holders of two-thirds of the voting shares other than shares beneficially owned by the interested shareholder. After three years, an affiliated transaction must be approved by the affirmative vote of the holders of two-thirds of the voting shares other than shares beneficially owned by the interested shareholder, unless the affiliated transaction is approved by a majority of the disinterested directors or meets “fair price” criteria. We have not made any election in our articles of incorporation not to be covered by this provision of the Virginia law.

Under Virginia law, voting rights for “control shares” must be approved by a corporation’s shareholders, not including the shares held by interested parties. “Control shares” are shares whose acquisition entitles the acquiror to between 1/5 and 1/3, between 1/3 and 1/2, or greater than 1/2 of a corporation’s voting power. If a shareholder has acquired control shares with a majority of all voting power and these shares have been given voting rights, all other shareholders have dissenters’ rights. Virginia law exempts from these provisions acquisitions where the corporation is a party to the governing agreement. We have not made any election not to be governed by these provisions of Virginia law. Our board of directors can elect not to be governed by these provisions at any time before four days after receipt of a control share acquisition notice.

Insurance Holding Company Regulations on Change of Control

We are regulated as an insurance holding company and are subject to state and foreign laws that restrict the ability of any person to obtain control of an insurance holding company without prior regulatory approval. Without this approval or an exemption, no person may acquire any voting security of an insurance holding company which controls an insurance subsidiary, or merge with the holding company. “Control” is generally defined as the direct or indirect power to direct or cause the direction of the management and policies of a person and is usually presumed to exist if a person directly or indirectly owns or controls 10% or more of the voting securities of another person.

Directors’ Duties

Under Virginia law, directors must discharge their duties in accordance with their good faith business judgment of the best interests of the corporation. Directors may rely on the advice or acts of others, including officers, employees, attorneys, accountants and board committees, if they have a good faith belief in their competence. Directors’ actions are not subject to a reasonable or prudent person standard. Virginia’s federal and state courts have focused on the process involved with directors’ decision-making and are generally supportive of directors if they have based their decision on an informed process. These elements of Virginia law could make it more difficult to take over a Virginia corporation than corporations in other states.

Preferred Shares

Our preferred shares are issuable in one or more series from time to time at the direction of the board of directors. The board of directors is authorized, with respect to each series, to fix its:

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The board of directors, without shareholder approval, can issue preferred shares with voting and conversion rights that could adversely affect the voting power of the holders of common shares. This right of issuance could be used as a method of preventing a party from gaining control of us. All preferred shares outstanding upon the consummation of any offering will be legally issued, fully paid and nonassessable.

The applicable prospectus supplement or other offering materials will describe the terms of any debt securities being offered, including:

If the purchase price of any debt securities is payable in a currency other than U.S. dollars or if principal of, or premium, if any, or interest, if any, on any of the debt securities is payable in any currency other than U.S. dollars, the specific terms and other information with respect to the debt securities and the foreign currency will be specified in the applicable prospectus supplement or other offering materials.

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Debt securities may be issued as original issue discount securities, as defined in the indentures, to be sold at a substantial discount below their principal amount. Original issue discount securities may include “zero coupon” securities that do not pay any cash interest for the entire term of the securities. In the event of an acceleration of the maturity of any original issue discount security, the amount payable to the holder upon acceleration will be determined in the manner described in the applicable prospectus supplement or other offering materials. Conditions under which payment of the principal of the subordinated debt securities may be accelerated will be set forth in the applicable prospectus supplement or other offering materials. Material federal income tax and other considerations applicable to original issue discount securities will be described in the applicable prospectus supplement or other offering materials.

Under the indentures, the terms of the debt securities of any series may differ and we, without the consent of the holders of the debt securities of any series, may reopen a previous series of debt securities and issue additional debt securities of that series or establish additional terms of that series, unless otherwise indicated in the applicable prospectus supplement or other offering materials.

Covenants

Under the indentures, we will be required to:

Any additional covenants will be described in the applicable prospectus supplement or other offering materials.

Registration, Transfer, Payment and Paying Agent

Unless otherwise indicated in a prospectus supplement or other offering materials, each series of debt securities will be issued in registered form only, without coupons. We may also issue debt securities in bearer form only, or in both registered and bearer form. Bearer securities will not be offered, sold, resold or delivered in connection with their original issuance in the United States or to any United States person other than to the offices located outside the United States of some United States financial institutions. Purchasers of bearer securities will be subject to certification procedures and may be affected by limitations under United States tax laws. These procedures and limitations will be described in the prospectus supplement or other offering materials relating to the offering of the bearer securities.

Unless otherwise indicated in a prospectus supplement or other offering materials, registered securities will be issued in denominations of $1,000 or any integral multiple thereof, and bearer securities will be issued in denominations of $5,000.

Unless otherwise indicated in a prospectus supplement or other offering materials, the principal, premium, if any, and interest, if any, of or on the debt securities will be payable, and debt securities may be surrendered for registration of transfer or exchange, at an office or agency of the trustee in the Borough of Manhattan, The City of New York, provided that payments of interest with respect to any registered security may be made at our option by check mailed to the address of the person entitled to payment or by transfer to an account maintained by the payee with a bank located in the United States. No service charge will be made for any registration of transfer or exchange of debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge and any other expenses that may be imposed in connection with the exchange or transfer.

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Unless otherwise indicated in a prospectus supplement or other offering materials, payment of principal of, premium, if any, and interest, if any, on bearer securities will be made, subject to any applicable laws and regulations, at the office or agency outside the United States as specified in the prospectus supplement or other offering materials and as we may designate from time to time. Unless otherwise indicated in a prospectus supplement or other offering materials, payment of interest due on bearer securities on any interest payment date will be made only against surrender of the coupon relating to the interest payment date. Unless otherwise indicated in a prospectus supplement or other offering materials, no payment of principal, premium or interest with respect to any bearer security will be made at any office or agency in the United States or by check mailed to any address in the United States or by transfer to an account maintained with a bank located in the United States, except that if amounts owing with respect to any bearer securities will be payable in U.S. dollars, payment may be made at the corporate trust office of the applicable trustee or at any office or agency designated by us in the Borough of Manhattan, The City of New York, but only if payment of the full amount of the principal, premium or interest at all offices outside of the United States maintained for this purpose by us is illegal or effectively precluded by exchange controls or similar restrictions.

Unless otherwise indicated in the applicable prospectus supplement or other offering materials, we will not be required to:

Ranking of Debt Securities; Holding Company Structure

The senior debt securities will be our unsubordinated obligations and will rank equally in right of payment with all our other unsubordinated indebtedness. The subordinated debt securities will be our obligations and will be subordinated in right of payment to all existing and future senior indebtedness, as specified in the applicable prospectus supplement or other offering materials. The prospectus supplement or other offering materials will describe the subordination provisions and set forth the definition of “senior indebtedness” applicable to the subordinated debt securities, and the approximate amount of the senior indebtedness outstanding as of a recent date.

Because we are a holding company that conducts all of our operations through our subsidiaries, our ability to meet our obligations under the debt securities is dependent on the earnings and cash flows of those subsidiaries and the ability of those subsidiaries to pay dividends or to advance or repay funds to us. Payment of dividends or advances from our insurance subsidiaries may require prior regulatory notice or approval. Holders of debt securities will generally have a junior position to claims of creditors of our subsidiaries, including insureds, trade creditors, debtholders, secured creditors, taxing authorities, guarantee holders and any preferred shareholders.

Global Securities

The debt securities of a series may be issued in whole or in part in the form of one or more global securities that will be deposited with, or on behalf of, a “depositary” identified in the prospectus supplement or other offering materials relating to that series. Global debt securities may be issued in either registered or bearer form

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and in either temporary or permanent form. Unless and until it is exchanged in whole or in part for individual certificates evidencing debt securities, a global debt security may not be transferred except as a whole:

The specific terms of the depositary arrangement with respect to a series of global debt securities and material limitations and restrictions relating to a series of global bearer securities will be described in the applicable prospectus supplement or other offering materials.

Redemption and Repurchase

The debt securities may be redeemable at our option, in whole or in part, or may be subject to mandatory redemption through a sinking fund or otherwise, in each case upon the terms, at the times and at the redemption price together with interest as set forth in the applicable prospectus supplement or other offering materials on notice given at least 20 days before the date of redemption. Senior and subordinated debt securities may be subject to repurchase by us at the option of the holders upon the terms, at the times and at the price together with interest set forth in the applicable prospectus supplement or other offering materials.

We must repay the senior and subordinated debt securities at the option of the holders before the stated maturity date only if specified in the applicable prospectus supplement or other offering materials. Unless otherwise provided, the senior and subordinated debt securities subject to repayment at the option of the holder will be subject to repayment:

For any senior or subordinated debt security to be repaid, the trustee must receive, at its office maintained for that purpose in the Borough of Manhattan, The City of New York not more than 60 nor less than 30 calendar days before the date of repayment:

Exercise of the repayment option by the holder will be irrevocable.

Only the securities depositary may exercise the repayment option in respect of beneficial interests in book-entry senior or subordinated debt securities. Accordingly, beneficial owners who desire repayment in respect of all or any portion of their beneficial interests must instruct the participants through which they own their interests to direct the securities depositary to exercise the repayment option on their behalf. All instructions given to participants from beneficial owners relating to the option to elect repayment will be irrevocable. In addition, at the time the instructions are given, each beneficial owner will cause the participant through which it owns its interest to transfer its interest in the book-entry senior or subordinated debt securities, or the global certificate representing the related book-entry senior or subordinated debt securities, to the trustee on the securities depositary’s records.

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Conversion and Exchange

The applicable prospectus supplement or other offering materials will set forth the terms, if any, on which debt securities of any series are convertible into or exchangeable for our common shares, preferred shares, or other debt securities. The terms may include provisions for conversion or exchange, either mandatory, at the option of the holders or at our option.

Absence of Limitation on Indebtedness and Liens; Absence of Event Risk Protection

The applicable prospectus supplement or other offering materials will specify any prohibitions on the amount of indebtedness, guarantees or other liabilities that may be incurred by us and any prohibitions on our ability to create or assume liens on our property. Unless otherwise provided in a prospectus supplement or other offering materials, the indentures will not require the maintenance of any financial ratios or specified levels of net worth, revenues, income, cash flow or liquidity, and will not contain provisions which would give holders of the debt securities the right to require us to repurchase their debt securities in the event of a takeover, recapitalization or similar restructuring or change in control of Markel.

Consolidation, Merger and Sale of Assets

Each indenture generally permits a consolidation or merger, subject to specified limitations and conditions, between us and another corporation. They also permit the sale by us of all or substantially all of our property and assets. If this happens, the remaining or acquiring corporation must assume all of our responsibilities and liabilities under the indentures including the payment of all amounts due on the debt securities and performance of the covenants in the indentures. Unless otherwise indicated in the applicable prospectus supplement or other offering materials, we must also deliver an opinion of counsel to the applicable trustee affirming our compliance with all conditions in the applicable indenture relating to the transaction. When the conditions are satisfied, the successor will succeed to and be substituted for us under the applicable indenture, and we will be relieved of our obligations under the applicable indenture and the debt securities issued under it.

Events of Default

Unless otherwise specified in the applicable prospectus supplement or other offering materials, an event of default with respect to any debt securities will include:

An event of default with respect to any particular series of debt securities will not necessarily constitute an event of default with respect to any other series of debt securities.

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Each indenture provides that if an event of default with respect to any series of debt securities issued under the indenture has occurred and is continuing, either the relevant trustee or the holders of at least a fixed percentage in principal amount of the debt securities of the series then outstanding may declare the principal amount, or if any debt securities of the series are original issue discount securities, a specified lesser amount, of all of the debt securities of the series to be due and payable immediately. However, upon specified conditions, the declaration and its consequences may be rescinded and annulled by the holders of a majority in principal amount of the debt securities of all series issued under the applicable indenture.

The applicable prospectus supplement or other offering materials will provide the terms under which an event of default will result in an acceleration of the payment of principal of subordinated debt securities.

In the case of a default in the payment of principal of, or premium, if any, or interest, if any, on any subordinated debt securities of any series, the applicable trustee, subject to specified limitations and conditions, may institute a judicial proceeding for collection.

No holder of any of debt securities of any series issued under any indenture has any right to institute any proceeding with respect to that indenture or any remedy under that indenture, unless the holders of at least a fixed percentage in principal amount of the outstanding debt securities of that series have made a written request, and offered reasonable indemnity, to the applicable trustee to institute a proceeding as trustee, the applicable trustee has failed to institute a proceeding within 60 days after receipt of the notice and the applicable trustee has not within the 60-day period received directions inconsistent with the written request by holders of a majority in principal amount of the outstanding debt securities of the series. These limitations do not apply, however, to a suit instituted by a holder of a debt security for the enforcement of the payment of the principal of, premium, if any, or any accrued and unpaid interest on, the debt security on or after the respective due dates expressed in the debt security.

Subject to the provisions of the applicable indenture relating to the duties of the applicable trustee, if an event of default occurs and is continuing, the applicable trustee is not under any obligation to exercise any of its rights or powers under the indenture at the request or direction of any of the holders unless those holders have offered to the applicable trustee reasonable security or indemnity. Subject to provisions concerning the rights of the applicable trustee, the holders of a majority in principal amount of the outstanding debt securities of any series 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 applicable trustee with respect to that series.

The applicable trustee may withhold notice to the holders of debt securities of any default, except in the payment of principal or interest, if it considers the withholding of notice to be in the best interests of the holders.

We are required to furnish to the trustees annually a statement as to compliance with all conditions and covenants under the indentures.

Modification and Waivers

From time to time, we, when authorized by resolutions of our board of directors, and the applicable trustee, without the consent of the holders of debt securities of any series, may amend, waive or supplement the indentures and the debt securities of the series for specified purposes, including, among other things:

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Other amendments and modifications of the indentures or the related debt securities may be made by us and the applicable trustee with the consent of the holders of at least a majority of the aggregate principal amount of the outstanding debt securities of each series that would be affected, with each series voting as a separate class; provided that no modification or amendment may, without the consent of the holder of each outstanding debt security that would be affected:

The holders of a majority in aggregate principal amount of the outstanding debt securities of any series may waive compliance by us with specified restrictive provisions of the relevant indenture, including other restrictive covenants, if any, that may be set forth in the applicable prospectus supplement or other offering materials. The holders of a majority in aggregate principal amount of the outstanding debt securities of any series may, on behalf of all holders of debt securities of that series, waive any past default under the applicable indenture with respect to debt securities of that series and its consequences, except a default in the payment of the principal of, or premium, if any, or interest, if any, on any debt securities of that series or in respect of a covenant or provision which cannot be modified or amended without the consent of a larger fixed percentage or by the holder of each outstanding debt security of the series affected.

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Satisfaction; Discharge

Except as described in this section, we may discharge all of our obligations to holders of the debt securities issued under the indentures, which debt securities have not already been delivered to the applicable trustee for cancellation and which either have become due and payable or are by their terms due and payable within one year, or are to be called for redemption within one year, by depositing with the applicable trustee an amount certified to be sufficient to pay when due the principal, interest and premium, if any, on all outstanding debt securities. However, some of our obligations under the indentures will survive, including the following:

Defeasance

We will be discharged from our obligations on the debt securities of any series at any time if we deposit with the applicable trustee sufficient cash or government securities to pay the principal, interest, any premium and any other sums due to the stated maturity date or a redemption date of the debt securities of the series. If this happens, the holders of the debt securities of the series will not be entitled to the benefits of the applicable indenture except for registration of transfer and exchange of debt securities and replacement of lost, stolen or mutilated debt securities.

Under federal income tax law as of the date of this prospectus, a discharge may be treated as an exchange of the related debt securities. Each holder might be required to recognize gain or loss equal to the difference between the holder’s cost or other tax basis for the debt securities and the value of the holder’s interest in the trust. Holders might be required to include as income a different amount than would be includable without the discharge. We urge prospective investors to consult their own tax advisers as to the consequences of a discharge, including the applicability and effect of tax laws other than the federal income tax law.

Governing Law

The indentures and the debt securities will be governed by, and construed in accordance with, the laws of the State of New York.

Regarding the Trustees

The Trust Indenture Act contains limitations on the rights of a trustee, should it become a creditor of ours, to obtain payment of claims in some cases or to realize on some property received by it in respect of those claims, as security or otherwise. Each trustee is permitted to engage in other transactions with us and our subsidiaries from time to time, provided that if that trustee acquires any conflicting interest it must eliminate that conflict upon the occurrence of an event of default under the relevant indenture, or else resign.

The Bank of New York Mellon is the trustee under our senior indenture and will be the trustee under our subordinated indenture. We and certain of our affiliates maintain deposit accounts and banking relationships with The Bank of New York Mellon and its affiliates. Affiliates of The Bank of New York Mellon have purchased, and may purchase in the future, our securities and securities of our affiliates. The Bank of New York Mellon administers its corporate trust business at 101 Barclay Street, 7W ATTN: Corporate Trust Administration, New York, New York 10286.

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Subordination of the Subordinated Debt Securities

Each series of subordinated debt securities will be subordinate and junior in right of payment, to the extent set forth in the applicable indenture, to all senior indebtedness as defined below. If:

then the holders of senior indebtedness generally will have the right to receive payment, in the case of the first instance, of all amounts due or to become due upon that senior indebtedness, and, in the case of the second and third instances, of all amounts due on that senior indebtedness, or we must make provision for those payments, before the holders of any subordinated debt securities have the right to receive any payments of principal or interest on their subordinated debt securities.

Senior indebtedness means, with respect to any series of subordinated debt securities, the principal, premium, interest and any other payment in respect of any of the following:

Senior indebtedness will be entitled to the benefits of the subordination provisions in the subordinated indenture irrespective of the amendment, modification or waiver of any term of the senior indebtedness. We may not amend the subordinated indenture to change the subordination of any outstanding subordinated debt securities without the consent of each holder of senior indebtedness that the amendment would adversely affect.

The subordinated indenture does not limit the amount of senior indebtedness that we may issue.

relationship of agency or trust for or with any holders or beneficial owners of warrants. If we offer warrants, we will file the warrant agreement relating to the offered warrants as an exhibit to, or incorporate it by reference in, the registration statement of which this prospectus is a part. The prospectus supplement or other offering materials relating to a particular issue of warrants will describe the terms of the warrants.

Reference Room of the SEC at 100 F Street, N.E., Washington, D.C. 20549. Information on the operation of the Public Reference Room may be obtained by calling the SEC at 1-800-SEC-0330. You may also inspect our filings over the Internet at the SEC’s home page at http://www.sec.gov.

INCORPORATION OF INFORMATION WE FILE WITH THE SEC

The SEC allows us to “incorporate by reference” the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and later information that we file with the SEC will automatically update and supersede this information and the information in the prospectus. We incorporate by reference the documents listed below:

You may request a copy of these filings at no cost, by writing or telephoning the office of Investor Relations, Markel Corporation, 4521 Highwoods Parkway, Glen Allen, Virginia 23060, telephone: (804) 747-0136, or e-mail at bkay@markelcorp.com.

$            

MARKEL CORPORATION

$                % Senior Notes due 2029

$                % Senior Notes due 2050

PROSPECTUS SUPPLEMENT

Joint Book-Running Managers

Wells Fargo Securities

Citigroup

J.P. Morgan

Barclays

                    , 2019