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Table of contents ( Mark One ) ☑ ☐ 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 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Commission File No. 001-36502 to COMMERCE BANCSHARES , INC . ( Exact name of registrant as specified in its charter ) Missouri ( State of Incorporation ) 43-0889454 ( IRS Employer Identification No. ) 1000 Walnut Kansas City , MO ( Address of principal executive offices ) 64106 ( Zip Code ) Registrant's telephone number , including area code : ( 816 ) 234-2000 Securities registered pursuant to Section 12 ( b ) of the Act : Title of class $ 5 Par Value Common Stock Trading symbol ( s ) CBSH Name of exchange on which registered NASDAQ Global Select Market 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 þ No " Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . Yes " No þ 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 þ 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 p 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 the definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company , " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . ( Check one ) : Large accelerated filer þ Accelerated Filer " Non - accelerated filer ¨ Smaller reporting company Emerging growth company 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 . Indicate by check mark whether the Registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes □ No As of June 30 , 2020 , the aggregate market value of the voting stock held by non - affiliates of the Registrant was approximately $ 6,146,000,000 . As of February 18 , 2021 , there were 117,078,437 shares of Registrant's $ 5 Par Value Common Stock outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant's definitive proxy statement for its 2021 annual meeting of shareholders , which will be filed within 120 days of December 31 , 2020 , are incorporated by reference into Part III of this Report .