Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of report (Date of earliest event reported): April 6, 2015 Commission File Number Exact Name of Registrant as Specified in Charter; State of Incorporation; Address and Telephone Number IRS Employer Identification Number 1-14756 Ameren Corporation (Missouri Corporation) 1901 Chouteau Avenue St. Louis, Missouri 63103 (314) 621-3222 43-1723446 1-2967 Union Electric Company (Missouri Corporation) 1901 Chouteau Avenue St. Louis, Missouri 63103 (314) 621-3222 43-0559760 Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) ITEM 8.01 Other Events. On April 6, 2015, Union Electric Company, doing business as Ameren Missouri (“Ameren Missouri”), a subsidiary of Ameren Corporation (“Ameren”), issued and sold $250,000,000 principal amount of its 3.65% Senior Secured Notes due 2045 (the “Notes”), pursuant to a Registration Statement on Form S-3 (File No. 333-182258-02), which became effective on June 21, 2012, and a Prospectus Supplement dated March 31, 2015, to a Prospectus dated June 21, 2012. Ameren Missouri received net offering proceeds of approximately $247.2 million, before expenses, upon the closing of the transaction. Ameren Missouri intends to use the net offering proceeds to repay outstanding short-term debt, including the short-term debt that Ameren Missouri incurred in connection with the repayment of $114 million aggregate principal amount of its 4.75% senior secured notes that matured on April 1, 2015. Ameren Missouri is filing this Current Report on Form 8-K to report as exhibits certain documents in connection with the offering of the Notes. ITEM 9.01 Financial Statements and Exhibits. (d) Exhibits Exhibit Number Title 1 Underwriting Agreement, dated March 31, 2015, between Ameren Missouri and the several underwriters named therein, for whom Mitsubishi UFJ Securities (USA), Inc., Morgan Stanley & Co. LLC, RBC Capital Markets, LLC and Wells Fargo Securities, LLC are acting as representatives. 4.1* Indenture dated as of August 15, 2002, from Ameren Missouri to The Bank of New York Mellon, as trustee, relating to the Notes (Current Report on Form 8-K, Exhibit 4.1, File No. 1-2967). 4.2 Company Order establishing the Notes. 4.3 Global Note. 4.4* Indenture of Mortgage and Deed of Trust dated June 15, 1937, from Ameren Missouri to The Bank of New York Mellon, as trustee, as amended May 1, 1941, and Second Supplemental Indenture dated May 1, 1941 (Exhibit B-1, File No. 2-4940). 4.5 Supplemental Indenture, dated as of March 15, 2015, by and between Ameren Missouri and The Bank of New York Mellon, as trustee, relating to the First Mortgage Bonds, Senior Notes Series QQ, securing the Notes. 5.1 Opinion of Gregory L. Nelson, Esq., Senior Vice President, General Counsel and Secretary of Ameren Missouri, regarding the legality of the Notes (including consent). 5.2 Opinion of Morgan, Lewis & Bockius LLP regarding the legality of the Notes (including consent). * Incorporated by reference as indicated. This combined Form 8-K is being filed separately by Ameren Corporation and Union Electric Company (each a “registrant”). Information contained herein relating to any individual registrant has been filed by such registrant on its own behalf. No registrant makes any representation as to information relating to any other registrant. - 2 - SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries. AMEREN CORPORATION (Registrant) By: /s/ Martin J. Lyons, Jr. Name: Martin J. Lyons, Jr. Title: Executive Vice President and Chief Financial Officer UNION ELECTRIC COMPANY (Registrant) By: /s/ Michael L. Moehn Name: Michael L. Moehn Title: Chairman and President Date: April 6, 2015 Exhibit Index Exhibit Number Title 1 Underwriting Agreement, dated March 31, 2015, between Ameren Missouri and the several underwriters named therein, for whom Mitsubishi UFJ Securities (USA), Inc., Morgan Stanley & Co. LLC, RBC Capital Markets, LLC and Wells Fargo Securities, LLC are acting as representatives. 4.2 Company Order establishing the Notes. 4.3 Global Note. 4.5 Supplemental Indenture, dated as of March 15, 2015, by and between Ameren Missouri and The Bank of New York Mellon, as trustee, relating to the First Mortgage Bonds, Senior Notes Series QQ, securing the Notes. 5.1 Opinion of Gregory L. Nelson, Esq., Senior Vice President, General Counsel and Secretary of Ameren Missouri, regarding the legality of the Notes (including consent). 5.2 Opinion of Morgan, Lewis & Bockius LLP regarding the legality of the Notes (including consent).