Reg FD Disclosure · 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): June 13, 2012 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 1-3672 Ameren Illinois Company (Illinois Corporation) 300 Liberty Street Peoria, Illinois 61602 (309) 677-5271 37-0211380 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 7.01 Regulation FD Disclosure. On June 13, 2012, Ameren Corporation (“Ameren”) issued a press release announcing the officer changes described under Item 8.01 below. A copy of the press release is furnished with this Form 8-K and attached hereto as Exhibit 99.1. Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities under that section and shall not be deemed to be incorporated by reference into any filing of Ameren under the Securities Act of 1933, as amended, or the Exchange Act. ITEM 8.01 Other Events. On June 13, 2012, Ameren announced that Scott A. Cisel, Chairman, President and Chief Executive Officer of Ameren Illinois Company, doing business as Ameren Illinois (“Ameren Illinois”), has left Ameren to pursue other interests. Effective immediately, Richard J. Mark, most recently the Senior Vice President, Customer Operations, of Union Electric Company, doing business as Ameren Missouri, assumed the positions of Chairman, President and Chief Executive Officer of Ameren Illinois, effective June 13, 2012. ITEM 9.01 Financial Statements and Exhibits. (d) Exhibits Exhibit Number Title 99.1 Press release, dated June 13, 2012. This combined Form 8-K is being filed separately by Ameren Corporation and Ameren Illinois 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) /s/ Martin J. Lyons, Jr. Martin J. Lyons, Jr. Senior Vice President and Chief Financial Officer AMEREN ILLINOIS COMPANY (Registrant) /s/ Martin J. Lyons, Jr. Martin J. Lyons, Jr. Senior Vice President and Chief Financial Officer Date: June 13, 2012