American Electric Power : Reopening of 5.800% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures, Series C, due 2056 & 6.050% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures Series D due 2056

Filed pursuant to Rule 424(b)(2) Registration No. 333-291275

Prospectus Supplement (To Prospectus dated November 24, 2025) $1,000,000,000 American Electric Power Company, Inc. $400,000,000 5.800% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures, Series C $600,000,000 6.050% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures, Series D

This is a public offering by American Electric Power Company, Inc. (the "Company") of $400,000,000 of its 5.800% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures, Series C (the "New Series C Debentures") and $600,000,000 of its 6.050% Fixed-to-Fixed Reset Rate Junior Subordinated Debentures, Series D (the "New Series D Debentures" and, collectively, the "New Debentures") . On September 25, 2025, the Company issued $1,100,000,000 of its Series C Debentures (the "Existing Series C Debentures" and, together with the New Series C Debentures, the "Series C Debentures") and

$900,000,000 of its Series D Debentures (the "Existing Series D Debentures" and, together with the New Series D Debentures, the "Series D Debentures", and the Existing Series C Debentures and Existing Series D Debentures, together, the "Existing Debentures", and the Series C Debentures and the Series D Debentures, together, the "Debentures"). The New Series C Debentures and the New Series D Debentures offered hereby will be treated as a single series with the Existing Series C Debentures and the Existing Series D Debentures, respectively, issued on September 25, 2025 and will have the same terms (other than issue date and issue price) as those of the Existing Series C Debentures and Existing Series D Debentures, respectively. Further, the New Series C Debentures and the New Series D Debentures are expected to have the same CUSIP and ISIN numbers as, and to be fungible for trading purposes with, the Existing Series C Debentures and the Existing Series D Debentures, respectively. Upon the issuance of the New Series C Debentures offered hereby, the aggregate principal amount of outstanding Series C Debentures will be $1,500,000,000. Upon the issuance of the New Series D Debentures offered hereby, the aggregate principal amount of outstanding Series D Debentures will be $1,500,000,000. The New Series C Debentures will bear interest (i) from and including the date of original issuance to, but excluding, March 15, 2031 at an annual rate of 5.800% and (ii) from and including March 15, 2031 during each Series C Interest Reset Period (as defined herein) at an annual rate equal to the Five-Year Treasury Rate (as defined herein) as of the most recent Series C Reset Interest Determination Date (as defined herein), plus 2.128%; provided, that the interest rate during any Series C Interest Reset Period will not reset below 5.800%. The New Series D Debentures will bear interest (i) from and including the date of original issuance to, but excluding, March 15, 2036 at an annual rate of 6.050% and (ii) from and including March 15, 2036 during each Series D Interest Reset Period (as defined herein) at an annual rate equal to the Five-Year Treasury Rate (as defined herein) as of the most recent Series D Reset Interest Determination Date (as defined herein), plus 1.940%; provided, that the interest rate during any Series D Interest Reset Period will not reset below 6.050%. Interest on the Debentures will be payable semi-annually in arrears on March 15 and September 15 of each year beginning on March 15, 2026. The New Debentures will be issued in registered form and in denominations of $2,000 and integral multiples of $1,000 in excess thereof. The New Debentures will mature on March 15, 2056.

So long as no event of default has occurred and is continuing, we may defer interest payments on either or both series of the Debentures on one or more occasions for up to 10 consecutive years as described in this prospectus supplement. Deferred interest payments with respect to a given series will accrue additional interest at a rate equal to the interest rate on such series, compounded on each interest payment date, to the extent permitted by law. We may redeem the Debentures at our option at the times and the prices described in this prospectus supplement. We do not intend to apply for listing of the Debentures on any securities exchange and cannot assure the holders that an active after-market for the Debentures has developed or will develop or be sustained or that holders of the Debentures will be able to sell them at favorable prices or at all.

Investing in the New Debentures involves risks. See "Risk Factors" on page S-14 of this prospectus supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the related prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

	Per New Series C Debenture		Total		Per New Series D Debenture	Total
Public offering price . . . . . . . . . . . . . . . . . . . . .	98.718%(1)		$394,872,000		98.160%(2)	$588,960,000
Underwriting discount . . . . . . . . . . . . . . . . . . . .	1.000 %		$4,000,000		1.000 %	$6,000,000
Proceeds, before expenses, to American Electric Power Company, Inc. . . . . . . . . . . . . . .	97.718 %		$390,872,000		97.160 %	$582,960,000

1. Plus accrued and unpaid interest from September 25, 2025 to the date of settlement (totaling $4,511,111.11). This accrued and unpaid interest must be paid by the purchaser of the New Series C Debentures offered hereby.

2. Plus accrued and unpaid interest from September 25, 2025 to the date of settlement (totaling $7,058,333.33). This accrued and unpaid interest must be paid by the purchaser of the New Series D Debentures offered hereby.

This prospectus supplement and the accompanying base prospectus are not intended to constitute an offer to, and the New Debentures should not be purchased, held or otherwise acquired by, a "specified foreign entity" as defined in Section 7701(a)(51)(B) of the Internal Revenue Code of 1986, as amended.

We expect that the New Debentures will be ready for delivery through The Depository Trust Company for the accounts of its participants, including Clearstream Banking S.A. and Euroclear Bank S.A./N.V., on or about December 5, 2025.

	Joint Book-Running Managers
Guggenheim Securities	J.P. Morgan	MUFG
PNC Capital Markets LLC	Scotiabank Co-Managers	Wells Fargo Securities

BNY Capital Markets CIBC Capital Markets Credit Agricole CIB TD Securities

December 3, 2025

TABLE OF CONTENTS Prospectus Supplement

Page

About this Prospectus Supplement S-4

Summary Information S-5

Risk Factors S-14

Where You Can Find More Information S-17

Use of Proceeds S-17

Specific Terms of the Fixed-To-Fixed Reset Rate Junior Subordinated Debentures S-18 Material United States Federal Income Tax Considerations S-29

Certain ERISA Considerations S-37

Underwriting (Conflicts of Interest) S-41

Legal Matters S-47

Experts S-47

Prospectus

Risk Factors	2
The Company	2
Prospectus Supplements	2
Where You Can Find More Information	3
Use of Proceeds	4
Description of the Senior Notes	4
Description of Common Stock	9
Description of Preferred Stock	12
Description of the Junior Subordinated Debentures	15
Description of the Stock Purchase Contracts and the Stock Purchase Units	22
Book-Entry System	19
Plan of Distribution	24
Legal Opinions	27
Experts	28

‌ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of the Debentures and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus, which gives more general information, some of which does not apply to the Debentures. If the description of the Debentures varies between this prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement.

You should rely only on the information contained or incorporated by reference in this prospectus supplement and in the accompanying prospectus and in any written communication from the Company or the underwriters specifying the final terms of the offering. We have not, and the underwriters have not, authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus is accurate as of the date on their respective covers. Our business, financial condition, results of operations and prospects may have changed since those respective dates.

‌SUMMARY INFORMATION

The following information supplements, and should be read together with, the information contained in the accompanying prospectus. You should carefully read this prospectus supplement and the accompanying prospectus as well as the documents they incorporate by reference, before making an investment decision. Unless we state otherwise or the context otherwise requires, references appearing in this prospectus supplement to the "Company", "we", "us" and "our" should be read to refer to American Electric Power Company, Inc. and its subsidiaries.

American Electric Power Company, Inc.

We are one of the largest investor-owned electric public utility holding companies in the United States. Our electric utility operating companies provide generation, transmission and distribution services to more than five million retail customers in Arkansas, Indiana, Kentucky, Louisiana, Michigan, Ohio, Oklahoma, Tennessee, Texas, Virginia and West Virginia.

Our portfolio of assets include:

• Approximately 252,000 circuit miles of distribution lines that deliver electricity to 5.6 million customers;

• Approximately 40,000 circuit miles of transmission lines, including approximately 2,100 circuit miles of 765 kV lines, the backbone of the electric interconnection grid in the eastern United States; and

• Approximately 30,000 MWs of diverse generating capacity, one of the largest complements of generation in the United States.

Our principal executive offices are located at 1 Riverside Plaza, Columbus, Ohio, and our telephone number is [phone].