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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K Annual report pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 for the fiscal year ended December 31 , 2020 Commission File Number 001-15811 MARKEL CORPORATION ( Exact name of registrant as specified in its charter ) A Virginia Corporation IRS Employer Identification No. 54-1959284 4521 Highwoods Parkway , Glen Allen , Virginia 23060-6148 ( Address of principal executive offices ) ( Zip code ) Registrant's telephone number , including area code : ( 804 ) 747-0136 Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Stock , no par value Large accelerated filer Smaller reporting company Trading Symbol ( s ) MKL Securities registered pursuant to Section 12 ( g ) of the Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes x No □ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes No X Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes x No X Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( § 232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes x No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company , " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Name of exchange on which registered New York Stock Exchange Accelerated filer Emerging growth company ☐ ☐ Non - accelerated filer If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . X No X Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes The aggregate market value of the shares of the registrant's Common Stock held by non - affiliates as of June 30 , 2020 was approximately $ 12,437,000,000 . The number of shares of the registrant's Common Stock outstanding at February 2 , 2021 : 13,783,813 . Documents Incorporated By Reference : The portions of the registrant's Proxy Statement for the Annual Meeting of Shareholders scheduled to be held on May 10 , 2021 , referred to in Part III .