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U 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 Transition Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 Illinois ( State or other jurisdiction of incorporation or organization ) For the Transition Period from to Commission File Number 001-35077 Wintrust Financial Corporation ( Exact name of registrant as specified in its charter ) Title of Each Class Common Stock , no par value Series D Preferred Stock , no par value Depositary Shares , Each Representing a 1 / 1,000th Interest in a Share of 6.875 % Fixed - Rate Non - Cumulative Perpetual Series E Preferred Stock , no par value 9700 W. Higgins Road , Suite 800 Rosemont , Illinois 60018 ( Address of principal executive offices ) Large accelerated filer Smaller reporting company ✔ Registrant's telephone number , including area code : ( 847 ) 939-9000 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . þ Yes " No 0 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 þ No Securities registered pursuant to Section 12 ( g ) of the Act : None WTFC WTFCM WTFCP 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 . þ 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 ) . þ Yes " No Accelerated filer Emerging growth company ( I.R.S. Employer Identification 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 definition of " large accelerated filer , " " accelerated filer , " " smaller reporting company , " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Non - Accelerated filer 36-3873352 0 Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes No As of February 22 , 2021 , the registrant had 56,891,238 shares of common stock outstanding . Name of Each Exchange on Which Registered The NASDAQ Global Select Market The NASDAQ Global Select Market The NASDAQ Global Select Market 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 controls 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 . þ Yes No The aggregate market value of the voting and non - voting common equity held by non - affiliates of the registrant on June 30 , 2020 ( the last business day of the registrant's most recently completed second quarter ) , determined using the closing price of the common stock on that day of $ 43.62 , as reported by the NASDAQ Global Select Market , was $ 2,490,791,184 . DOCUMENTS INCORPORATED BY REFERENCE Portions of the Proxy Statement for the Company's Annual Meeting of Shareholders to be held on May 27 , 2021 are incorporated by reference into Part III .