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( Mark One ) 0 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 Delaware ( State or Other Jurisdiction of Incorporation or Organization ) 20 South Wacker Drive Large Accelerated Filer Non - accelerated filer FORM 10 - K Commission File Number 001-31553 CME GROUP INC . ( Exact name of registrant as specified in its charter ) Title Of Each Class Class A Common Stock $ 0.01 par value X 0 ( Address of Principal Executive Offices ) Chicago Registrant's telephone number , including area code : ( 312 ) 930-1000 Securities registered pursuant to Section 12 ( b ) of the Act : Trading symbol CME Illinois Securities registered pursuant to Section 12 ( g ) of the Act : Class B common stock , Class B - 1 , $ 0.01 par value ; Class B common stock , Class B - 2 , $ 0.01 par value ; Class B common stock , Class B - 3 , $ 0.01 par value ; and Class B common stock , Class B - 4 , $ 0.01 par value . Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes 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 □ No | 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 , 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 Each Exchange On Which Registered Nasdaq 36-4459170 ( IRS Employer Identification No. ) 60606 ( Zip Code ) Accelerated filer Smaller reporting company Emerging growth company Documents Portions of CME Group Inc.'s Proxy Statement for the 2021 Annual Meeting of Shareholders 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 . Yes No DOCUMENTS INCORPORATED BY REFERENCE : Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes □ No The aggregate market value of the voting stock held by non - affiliates of the registrant as of June 30 , 2020 , was approximately $ 57.9 billion ( based on the closing price per share of CME Group Inc. Class A common stock on the Nasdaq Global Select Market ( Nasdaq ) on such date ) . The number of shares outstanding of each of the registrant's classes of common stock as of February 10 , 2021 was as follows : 359,003,437 shares of Class A common stock , $ 0.01 par value ; 625 shares of Class B common stock , Class B - 1 , $ 0.01 par value ; 813 shares of Class B common stock , Class B - 2 , $ 0.01 par value ; 1,287 shares of Class B common stock , Class B - 3 , $ 0.01 par value ; and 413 shares of Class B common stock , Class B - 4 , $ 0.01 par value . 0 0 0 Form 10 - K Reference Part III