AEE: Other company developments

ITEM 8.01 Other Events. On September 18, 2026, Ameren Corporation (“Ameren”) sold $900 million principal amount of its Junior Subordinated Notes due 2057 (the “Notes”). The Notes were offered pursuant to a Registration Statement on Form S-3 (File No. 333-297949), which became effective on August 4, 2026, and a Prospectus Supplement dated September 8, 2026, to a Prospectus dated August 4, 2026. Ameren received net offering proceeds of $891.0 million, before expenses, upon closing of the transaction. This Current Report on Form 8-K is being filed 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 September 8, 2026, between Ameren and the several underwriters named therein, for whom Barclays Capital Inc., BofA Securities, Inc., J.P. Morgan Securities LLC, Morgan Stanley & Co. LLC, MUFG Securities Americas Inc. and Truist Securities, Inc. are acting as representatives. 4.1 Indenture, dated as of September 1, 2026, by and between Ameren and The Bank of New York Mellon Trust Company, N.A., as trustee (“Ameren Indenture”). 4.2 Company Order, dated September 18, 2026, establishing the Notes. 4.3 Global Notes. 5.1 Opinion of David M. Feinberg, Esq., Executive Vice President, General Counsel and Secretary of Ameren, regarding the legality of the Notes (including consent). 5.2 and 8 Opinion of Morgan, Lewis & Bockius LLP (including consent). 104 Cover Page Interactive Data File (formatted as Inline XBRL). - 2 - SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, Ameren has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. AMEREN CORPORATION (Registrant) By: /s/ Leo