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): October 2, 2025

AMEREN CORPORATION

(Exact Name of Registrant as Specified in Charter)

Missouri	1-14756	43-1723446
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification Number)

1901 Chouteau Avenue, St. Louis, Missouri 63103

(Address of principal executive offices and Zip Code)

Registrant’s telephone number, including area code: (314) 621-3222

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))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.01 par value per share	AEE	New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

ITEM 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On and effective October 2, 2025 (the "Effective Date"), Mark C. Birk informed Ameren Corporation (the "Company") of his decision to retire from his position as Chairman and President of Union Electric Company, doing business as Ameren Missouri ("Ameren Missouri"), and from each other position he holds with subsidiaries of the Company.

As of the Effective Date, Michael L. Moehn, who currently serves as the Company's Senior Executive Vice President and Chief Financial Officer, has been elected to the additional position of Interim Chairman and President of Ameren Missouri. Mr. Moehn has served as the Company's Chief Financial Officer since 2019 and previously served as Chairman and President of Ameren Missouri from 2014 to 2019.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	AMEREN CORPORATION
	(Registrant)

	By:	/s/ Stephen C. Lee
	Name:	Stephen C. Lee
	Title:	Vice President, Interim General Counsel and Secretary

Date: October 3, 2025