Form 8-K

8-K — AMEREN CORP

Accession: 0001104659-26-090493

Filed: 2026-08-04

Period: 2026-07-31

CIK: 0001002910

SIC: 4931 (ELECTRIC & OTHER SERVICES COMBINED)

Item: Other Events

Item: Financial Statements and Exhibits

Documents

8-K — tm2621886d1_8k.htm (Primary)

EX-5 — EXHIBIT 5 (tm2621886d1_ex5.htm)

GRAPHIC (tm2621886d1_ex5img001.jpg)

GRAPHIC (tm2621886d1_ex5img002.jpg)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K — FORM 8-K

8-K (Primary)

Filename: tm2621886d1_8k.htm · Sequence: 1

false

0001002910

2026-07-31

iso4217:USD

xbrli:shares

iso4217:USD

xbrli:shares

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): July 31, 2026

AMEREN CORPORATION

(Exact name of registrant as specified in its charter)

Missouri

1-14756

43-1723446

(State of other jurisdiction

of incorporation

(Commission

File Number)

(I.R.S. Employer

Identification

No.)

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 8.01 Other Events.

On July 31, 2026, Ameren Corporation (the “Company”)

delivered a notice pursuant to Section 3(x) of its Equity Distribution Sales Agreement dated May 12, 2021, as amended and supplemented,

including by the First Amendment to Equity Distribution Sales Agreement dated August 7, 2025 (as so amended and supplemented, the “Sales

Agreement”), with Barclays Capital Inc., BofA Securities, Inc., Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, Mizuho

Securities USA LLC, Morgan Stanley & Co. LLC, MUFG Securities Americas Inc., RBC Capital Markets, LLC and Wells Fargo Securities,

LLC, as sales agents and as forward sellers (in such capacities as applicable, the “Agents” and the “Forward Sellers”),

and Bank of America, N.A., Barclays Bank PLC, Goldman Sachs & Co. LLC, JPMorgan Chase Bank, National Association, Mizuho Markets Americas

LLC, Morgan Stanley & Co. LLC, MUFG Securities EMEA plc, Royal Bank of Canada and Wells Fargo Bank, National Association, as forward

purchasers (the “Forward Purchasers”), increasing by $2,000,000,000 the aggregate gross sales price authorized under the Company’s

equity distribution program (the “Program”), pursuant to which the Company, through the Agents or the Forward Sellers, may

offer and sell from time to time shares of the Company’s common stock, par value $0.01 per share (the “Common Stock”).

After giving effect to such increase, Common Stock with an aggregate gross sales price of up to $2,266,700,000 remains available for issuance

under the Program. The Company has no obligation to offer or sell any Common Stock under the Sales Agreement and may at any time suspend

offers under the Sales Agreement.

This Current Report on Form 8-K is also being filed

to report Exhibit 5.

ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number

Title

5 Opinion of David M. Feinberg, Esq., Executive Vice President, General Counsel and Secretary of the

Company, regarding the legality of the Common Stock (including consent).

104 Cover Page Interactive Data File (formatted as Inline XBRL)

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/ Leonard P. Singh

Name:

Leonard P. Singh

Title:

Executive Vice President and

Chief Financial Officer

Date: August 4, 2026

EX-5 — EXHIBIT 5

EX-5

Filename: tm2621886d1_ex5.htm · Sequence: 2

Exhibit 5

August 4, 2026

Ameren Corporation

1901 Chouteau Avenue

St. Louis, Missouri 63103

Ladies and Gentlemen:

I am Executive Vice President, General Counsel and Secretary of Ameren

Corporation, a Missouri corporation (the “Company”). The Company has filed with the Securities and Exchange Commission (the

“Commission”) a Registration Statement on Form S-3 (Registration No. 333-297949) (the “Registration Statement”)

under the Securities Act of 1933, as amended (the “Securities Act”), with respect to the registration of an indeterminate

amount of securities, which became effective on August 4, 2026.

In connection with the offering of shares of the Company’s common

stock, $.01 par value per share (the “Shares”), by the Company pursuant to the Registration Statement having an aggregate

gross sales price of up to $2,266,700,000, I or persons under my supervision and control have reviewed originals (or copies certified

or otherwise identified to my satisfaction) of (1) the Registration Statement; (2) a prospectus dated August 4, 2026 (the “Base

Prospectus”) forming a part of the Registration Statement, as supplemented by a prospectus supplement dated August 4, 2026 (the

“Prospectus Supplement”), both such Base Prospectus and Prospectus Supplement filed pursuant to Rule 424 under the Securities

Act; (3) the Company’s Restated Articles of Incorporation, as amended, and By-Laws, as amended, each as in effect on the date

hereof; (4) the Equity Distribution Sales Agreement, dated May 12, 2021, as amended and supplemented, including by the First Amendment

to Equity Distribution Sales Agreement, dated August 7, 2025 (as so amended and supplemented, the “Sales Agreement”), with

Barclays Capital Inc., BofA Securities, Inc., Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, Mizuho Securities USA LLC, Morgan

Stanley & Co. LLC, MUFG Securities Americas Inc., RBC Capital Markets, LLC and Wells Fargo Securities, LLC, as sales agents and as

forward sellers (in such capacities as applicable, the “Agents” and the “Forward Sellers”), and Bank of America,

N.A., Barclays Bank PLC, Goldman Sachs & Co. LLC, JPMorgan Chase Bank, National Association, Mizuho Markets Americas LLC, Morgan Stanley

& Co. LLC, MUFG Securities EMEA plc, Royal Bank of Canada and Wells Fargo Bank, National Association, as forward purchasers (the “Forward

Purchasers”); (5) the separate letter agreements, dated May 12, 2021 and August 7, 2025, as applicable for each such Forward

Purchaser, in the form attached as Exhibit C to the Sales Agreement (each, a “Forward Confirmation”) entered into with

respect to the Forward Purchasers; and (6) corporate and other documents, records and papers and certificates of public officials.

In addition, I or persons under my supervision and control have discussed

and conferred with officers and employees of the Company and its subsidiaries and reviewed such other documents and materials as I have

deemed necessary or appropriate for purposes of this opinion. In connection with such review, I have assumed the genuineness of all signatures,

the legal capacity of natural persons, the conformity to the originals of the documents submitted to me as certified or photostatic copies,

the authenticity of the originals of such documents and all documents submitted to me as originals and the correctness of all statements

of fact contained in such original documents.

On the basis of such review, I am of the opinion that (1) the Shares

to be issued and sold by the Company pursuant to the Sales Agreement, when duly authorized, issued and delivered by the Company in accordance

with the Sales Agreement against payment of the consideration contemplated thereby, will be validly issued, fully paid and non-assessable

and (2) when the terms of a supplemental forward confirmation to a Forward Confirmation and of the issue and sale of the Shares pursuant

thereto have been duly authorized and established in accordance with the Sales Agreement, and when issued upon physical settlement or

net share settlement, as applicable, in accordance with such Forward Confirmation (and such related supplemental forward confirmation)

and against payment of the consideration contemplated thereby, such Shares will be validly issued, fully paid and non-assessable.

This opinion is limited to the laws of the State of Missouri.

I hereby consent to the reference to me under the heading “Legal

Matters” in each of the Base Prospectus and the Prospectus Supplement, to the references to me in the Registration Statement, including

under the heading “Legal Matters” in the Base Prospectus, and to the filing of this opinion as an exhibit to the Company’s

Current Report on Form 8-K to be filed on or about the date hereof, which will be incorporated by reference in the Registration Statement.

In giving the foregoing consents, I do not thereby admit that I am within the category of persons whose consent is required under Section 7

of the Securities Act or the rules and regulations of the Commission thereunder.

Very truly yours,

/s/ David M. Feinberg

David M. Feinberg, Esq.

Executive Vice President, General

Counsel & Secretary

Ameren Corporation

GRAPHIC

Filename: tm2621886d1_ex5img001.jpg · Sequence: 6

Binary file (4608 bytes)

Download tm2621886d1_ex5img001.jpg

GRAPHIC

Filename: tm2621886d1_ex5img002.jpg · Sequence: 7

Binary file (9138 bytes)

Download tm2621886d1_ex5img002.jpg

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 9

v3.26.1

Cover

Jul. 31, 2026

Cover [Abstract]

Document Type

8-K

Amendment Flag

false

Document Period End Date

Jul. 31, 2026

Entity File Number

1-14756

Entity Registrant Name

AMEREN CORPORATION

Entity Central Index Key

0001002910

Entity Tax Identification Number

43-1723446

Entity Incorporation, State or Country Code

Entity Address, Address Line One

1901 Chouteau Avenue

Entity Address, City or Town

St. Louis

Entity Address, State or Province

Entity Address, Postal Zip Code

63103

City Area Code

314

Local Phone Number

621-3222

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common

Stock, $0.01 par value per share

Trading Symbol

AEE

Security Exchange Name

NYSE

Entity Emerging Growth Company

false

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Cover page.

+ References

No definition available.

+ Details

Name:

dei_CoverAbstract

Namespace Prefix:

dei_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration