Page 1

( Mark One ) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 FORM 10 - K TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Commission File Number : 001-15373 or Common Stock , par value $ .01 per share ( Title of each class ) Large accelerated filer Non - accelerated filer to ENTERPRISE FINANCIAL SERVICES CORP ( Exact name of registrant as specified in its charter ) Incorporated in the State of Delaware I.R.S. Employer Identification # 43-1706259 Address : 150 North Meramec Avenue , Clayton , MO 63105 Telephone : ( 314 ) 725-5500 Securities registered pursuant to Section 12 ( b ) of the Act : EFSC ( Trading Symbol ) 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 Nasdaq Global Select Market ( Name of each exchange on which registered ) 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 . 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 Act ) . Yes Nox The aggregate market value of the voting and non - voting common stock held by non - affiliates of the Registrant was approximately $ 740,426,000 based on the closing price of the common stock of $ 31.12 as of the last business day of the registrant's most recently completed second fiscal quarter ( June 30 , 2020 ) as reported by the Nasdaq Global Select Market . As of February 17 , 2021 , the Registrant had 31,225,229 shares of outstanding common stock . DOCUMENTS INCORPORATED BY REFERENCE