Free Writing Prospectus (Form FWP)

Filed pursuant to Rule 433

Registration No. 333-282060

March 5, 2026

PRICING TERM SHEET

Issuer:

Southwestern Electric Power Company

Expected Ratings*:

Baa2 (Stable) by Moody's Investors Service, Inc. BBB+ (Stable) by S&P Global Ratings, a division of S&P Global Inc. BBB+ (Stable) by Fitch Ratings, Inc.

Transaction Date:

March 5, 2026

Settlement Date:

March 9, 2026 (T+2)

Designation:

Senior Notes, Series P, due 2033

Senior Notes, Series Q, due 2036

Senior Notes, Series R, due 2056

Principal Amount:

$300,000,000

$600,000,000

$500,000,000

Maturity:

April 1, 2033

April 1, 2036

April 1, 2056

Coupon:

5.30%

5.20%

5.90%

Interest Payment Dates:

April 1 and October 1

April 1 and October 1

April 1 and October 1

First Interest Payment Date:

April 1, 2026

October 1, 2026

October 1, 2026

Treasury Benchmark:

4.125% due February 15, 2036

4.125% due February 15, 2036

4.625% due November 15, 2055

Treasury Yield:

4.144%

4.144%

4.757%

Reoffer Spread:

T+72 basis points

T+107 basis points

T+117 basis points

Yield to Maturity:

4.864%

5.214%

5.927%

Price to Public:

102.505% of the principal amount thereof, plus accrued interest from October 1, 2025 (totaling $6,978,333.33)

99.887% of the principal amount thereof

99.617% of the principal amount thereof

Redemption Terms:

Make-whole call:

Prior to January 1, 2033 at a discount rate of the Treasury Rate plus 30 basis points

Prior to January 1, 2036 at a discount rate of the Treasury Rate plus 20 basis points

Prior to October 1, 2055 at a discount rate of the Treasury Rate plus 20 basis points

Par call:

On or after January 1, 2033 at par

On or after January 1, 2036 at par

On or after October 1, 2055 at par

CUSIP/ISIN:

845437 BU5/US845437BU53

845437 BV3/US845437BV37

845437 BW1/US845437BW10

Minimum Denomination:

$2,000 and integral multiples of $1,000 in excess thereof

Joint Book-Running Managers:

BNY Mellon Capital Markets, LLC Huntington Securities, Inc. Mizuho Securities USA LLC Scotia Capital (USA) Inc.

Co-Managers:

Fifth Third Securities, Inc. PNC Capital Markets LLC Truist Securities, Inc. U.S. Bancorp Investments, Inc.

*Note: A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by contacting BNY Mellon Capital Markets, LLC toll-free at (800) 269, 6864, Huntington Securities, Inc. toll-free at (800) 824 5652, Mizuho Securities USA LLC toll-free at (866) 271-7403 or Scotia Capital (USA) Inc. toll-free at (800) 372-3930.