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)			September 16, 2025

Commission
File Number

Registrant,
State of Incorporation,
Address and Telephone Number

I.R.S. Employer
Identification No.

001-37803

Southern Power Company

58-2598670

(A Delaware Corporation)

30 Ivan Allen Jr. Boulevard, N.W.

Atlanta, Georgia 30308

(404) 506-5000

The name and address of the registrant have not changed since the last report.

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:


Registrant	Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Southern Power Company	Series 2016B 1.850% Senior Notes due 2026	SO/26A	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).

Emerging growth company ☐

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 September 16, 2025, Southern Power Company (the “Company”) entered into Underwriting Agreements covering the issue and sale of $550,000,000 aggregate principal amount of its Series 2025A 4.25% Senior Notes due October 1, 2030 (the “Series 2025A Senior Notes”) and $550,000,000 aggregate principal amount of its Series 2025B 4.90% Senior Notes due October 1, 2035 (the “Series 2025B Senior Notes”). Both the Series 2025A Senior Notes and the Series 2025B Senior Notes were registered under the Securities Act of 1933, as amended, pursuant to the shelf registration statement (Registration No. 333-289172) of the Company.


Item 9.01.			Financial Statements and Exhibits.


(d) Exhibits.
1.2(a)			Underwriting Agreement relating to the Series 2025A Senior Notes, dated September 16, 2025, among the Company and BMO Capital Markets Corp., Mizuho Securities USA LLC, PNC Capital Markets LLC and SMBC Nikko Securities America, Inc., as representatives of the several Underwriters named in Schedule I thereto.

1.2(b)			Underwriting Agreement relating to the Series 2025B Senior Notes, dated September 16, 2025, among the Company and BMO Capital Markets Corp., Mizuho Securities USA LLC, PNC Capital Markets LLC and SMBC Nikko Securities America, Inc., as representatives of the several Underwriters named in Schedule I thereto.

4.6(a)			First Supplemental Indenture to Senior Note Indenture dated as of September 19, 2025, providing for the issuance of the Series 2025A Senior Notes.

4.6(b)			Second Supplemental Indenture to Senior Note Indenture dated as of September 19, 2025, providing for the issuance of the Series 2025B Senior Notes.

4.9(a)			Form of the Series 2025A Senior Note (included in Exhibit 4.6(a) above).

4.9(b)			Form of the Series 2025B Senior Note (included in Exhibit 4.6(b) above).

5.1(a)			Opinion of Troutman Pepper Locke LLP relating to the Series 2025A Senior Notes.

5.1(b)			Opinion of Troutman Pepper Locke LLP relating to the Series 2025B Senior Notes.

8.1(a)			Tax Opinion of Troutman Pepper Locke LLP relating to the Series 2025A Senior Notes.


8.1(b)			Tax Opinion of Troutman Pepper Locke LLP relating to the Series 2025B Senior Notes.

23.1			Consent of Troutman Pepper Locke LLP (included in Exhibit 5.1(a) above) .

23.2			Consent of Troutman Pepper Locke LLP (included in Exhibit 5.1(b) above) .

23.3			Consent of Troutman Pepper Locke LLP (included in Exhibit 8.1(a) above).

23.4			Consent of Troutman Pepper Locke LLP (included in Exhibit 8.1(b) above).

104			Cover Page Interactive Data File – The cover page iXBRL tags are embedded within the inline XBRL document.

SIGNATURE

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.


Date: September 19, 2025	SOUTHERN POWER COMPANY
	By	/s/Melissa K. Caen
		Melissa K. Caen Assistant Secretary

SOUTHERN POWER CO 8-K