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Table of Contents 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 , 2 2020 OR Transition report pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 for the transition period from to Ameren MISSOURI Commission File Number 1-14756 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 1-2967 1-3672 Ameren Exact name of registrant as specified in its charter ; State of Incorporation ; Address and Telephone Number Ameren Corporation ( Missouri Corporation ) 1901 Chouteau Avenue St. Louis , Missouri 63103 ( 314 ) 621-3222 Union Electric Company Title of each class Common Stock , $ 0.01 par value per share ( Missouri Corporation ) 1901 Chouteau Avenue St. Louis , Missouri 63103 ( 314 ) 621-3222 Ameren Illinois Company ( Illinois Corporation ) 10 Executive Drive Collinsville , Illinois 62234 ( 618 ) 343-8150 Trading Symbol ( s ) AEE Securities Registered Pursuant to Section 12 ( b ) of the Act : The following security is registered pursuant to Section 12 ( b ) of the Securities Exchange Act of 1934 and is listed on the New York Stock Exchange : Securities Registered Pursuant to Section 12 ( g ) of the Act : Registrant Union Electric Company Ameren Illinois Company Ameren ILLINOIS Title of each class IRS Employer Identification No. 43-1723446 43-0559760 37-0211380 Name of each exchange on which registered New York Stock Exchange Preferred Stock , cumulative , no par value , stated value $ 100 per share Preferred Stock , cumulative , $ 100 par value Depositary Shares , each representing 1/4 of a share of 6.625 % Preferred Stock , cumulative , $ 100 par value Indicate by checkmark if each registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act .