Ameren Corporation and its subsidiary Ameren Illinois Company filed a combined Form 8-K on August 24, 2026, reporting the sale of $400 million in First Mortgage Bonds due 2036.

Key Highlights

  • Bond sale: Ameren Illinois Company sold $400 million principal amount of 5.50% First Mortgage Bonds due 2036 on August 24, 2026.
  • Net proceeds: Ameren Illinois received net offering proceeds of approximately $397.4 million, before expenses.
  • Prospectus Supplement: The Bonds were offered under a Prospectus Supplement dated August 17, 2026, to a Prospectus dated August 4, 2026.
  • Registration Statement: The offering was made pursuant to a Registration Statement on Form S-3 (File No. 333-297949-01), which became effective on August 4, 2026.
  • Underwriting representatives: Goldman Sachs & Co. LLC, KeyBanc Capital Markets Inc., SMBC Nikko Securities America, Inc., and TD Securities (USA) LLC acted as representatives for the underwriters.
  • Trustee: The Bank of New York Mellon Trust Company, N.A. serves as successor trustee under the General Mortgage Indenture and Deed of Trust.

Ameren Illinois Completes First Mortgage Bond Offering Under Form S-3

According to the filing, Ameren Illinois Company, a subsidiary of Ameren Corporation (NYSE:AEE), sold $400 million principal amount of its 5.50% First Mortgage Bonds due 2036 on August 24, 2026. The company disclosed that net offering proceeds were approximately $397.4 million, before expenses, upon closing of the transaction.

The filing states that the Bonds were offered pursuant to a Registration Statement on Form S-3 (File No. 333-297949-01), which became effective on August 4, 2026, and a Prospectus Supplement dated August 17, 2026. The Underwriting Agreement, dated August 17, 2026, was entered into between Ameren Illinois and the several underwriters named therein, with Goldman Sachs & Co. LLC, KeyBanc Capital Markets Inc., SMBC Nikko Securities America, Inc., and TD Securities (USA) LLC acting as representatives.

The combined Form 8-K was filed separately by Ameren Corporation and Ameren Illinois Company. The filing notes that "no registrant makes any representation as to information relating to any other registrant." Among the exhibits filed are a Supplemental Indenture dated as of August 1, 2026, and legal opinions from David M. Feinberg, Esq., Executive Vice President, General Counsel and Secretary of Ameren Illinois, and from Morgan, Lewis & Bockius LLP, each regarding the legality of the Bonds.

What Was Disclosed

Ameren Illinois Company reported the closing of a $400 million, 5.50% First Mortgage Bond offering due 2036, generating approximately $397.4 million in net proceeds before expenses, with related transaction documents filed as exhibits.