Page 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 Form 10 - K ( Mark One ) ✓ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Commission File Number 001-34091 MARKETAXESS HOLDINGS INC . ( Exact name of registrant as specified in its charter ) Delaware ( State of incorporation ) 55 Hudson Yards , New York , New York ( Address of principal executive offices ) Title of each class Common Stock , $ 0.003 par value Large accelerated filer Non - accelerated filer to ( 212 ) 813-6000 ( Registrant's telephone number , including area code ) SECURITIES REGISTERED PURSUANT TO SECTION 12 ( b ) OF THE ACT : Trading Symbol MKTX 52-2230784 ( IRS Employer Identification No. ) 10001 ( Zip Code ) ✓✔ Name of each exchange on which registered NASDAQ Global Select Market SECURITIES REGISTERED PURSUANT TO SECTION 12 ( g ) OF THE ACT : None Yes No Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . Yes □ 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 No 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 No □ Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , smaller reporting company , or an emerging growth company . See definition of " large accelerated filer , " " accelerated filer , " " smaller reporting company " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Accelerated filer Smaller reporting company Emerging growth company No ■ 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 . ✔ No Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes The aggregate market value of the shares of common stock held by non - affiliates of the registrant as of June 30 , 2020 ( the last business day of the registrant's most recently completed second fiscal quarter ) was approximately $ 16.3 billion computed by reference to the last reported sale price on the NASDAQ Global Select Market on that date . For purposes of this calculation , affiliates are considered to be officers , directors and holders of 10 % or more of the outstanding common stock of the registrant on that date . The registrant had 37,964,515 shares of common stock , 5,492,071 of which were held by affiliates , outstanding on that date . As of February 16 , 2021 , the aggregate number of shares of the registrant's common stock outstanding was 37,995,877 . DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive proxy statement for the 2021 Annual Meeting of Stockholders are incorporated by reference into Items 10 , 11 , 12 , 13 and 14 of Part III of this Form 10 - K .