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Table of Contents 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 : 001-32550 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 Delaware ( State or other jurisdiction of incorporation or organization ) One E. Washington Street , Suite 1400 Phoenix ( Address of principal executive offices ) Title of each class Common Stock , $ 0.0001 Par Value 6.25 % Subordinated Debentures due 2056 FORM 10 - K WESTERN ALLIANCE BANCORPORATION ( Exact name of registrant as specified in its charter ) Large accelerated filer Non - accelerated filer | to Arizona ( I.R.S. Employer Identification No. ) ( 602 ) 389-3500 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : 88-0365922 Trading Symbol ( s ) . WAL WALA Securities registered pursuant to Section 12 ( g ) of the Act : None 85004 ( Zip Code ) No No X 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 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 Name of each exchange on which registered New York Stock Exchange New York Stock Exchange 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 , or a smaller reporting company , or 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 000 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 The aggregate market value of the registrant's voting stock held by non - affiliates was approximately $ 3.54 billion based on the June 30 , 2020 closing price of said stock on the New York Stock Exchange ( $ 37.87 per share ) . As of February 19 , 2021 , Western Alliance Bancorporation had 101,097,102 shares of common stock outstanding . Portions of the registrant's definitive proxy statement for its 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this report .