Company: SOJE
Filing Date: 2025-11-04
Form Type: 424B2
Source: 0000092122-25-000092
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Company: SOUTHERN CO
Filing Date: 2025-11-04
Form: 424B2
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Filed Pursuant to Rule 424(b)(2)

Registration No. 333-277138

PROSPECTUS SUPPLEMENT

(To Prospectus Dated February 16, 2024)

#### 35,000,000 2025 Series A Equity Units
<div align='center'>(Initially Consisting of 35,000,000 2025 Series A Corporate Units)</div>

This is an offering of 2025 Series A Equity Units (“Equity Units”) by The Southern Company (the “Company” or “Southern Company”). Each Equity Unit will have a stated amount of $50 and initially will be in the form of a 2025 Series A Corporate Unit (“Corporate Unit”) consisting of (i) a purchase contract issued by the Company, (ii) a 1/40 undivided beneficial ownership interest in $1,000 principal amount of the Company’s Series 2025B Remarketable Senior Notes due 2030 (“Series 2025B RSNs”) and (iii) a 1/40 undivided beneficial ownership interest in $1,000 principal amount of the Company’s Series 2025C Remarketable Senior Notes due 2033 (“Series 2025C RSNs” and, together with the Series 2025B RSNs, the “RSNs”). Each series of RSNs will initially bear interest at the rate of 4.15% per annum, payable quarterly, subject to reset following a successful remarketing as described herein.

The Company intends to apply to list the Corporate Units on the New York Stock Exchange and expects trading to commence within 30 days of the date of initial issuance of the Corporate Units under the symbol “SOMN”, but there is no guarantee that such listing will be approved. Prior to this offering, there has been no public market for the Corporate Units.

The Company’s common stock is listed on the New York Stock Exchange under the symbol “SO”. The closing price of the Company’s common stock on November 3, 2025 was $93.15 per share.

Investing in the Equity Units involves certain risks. See the “Risk Factors” section beginning on page S-28 of this Prospectus Supplement, as well as under “Risk Factors” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 , which is incorporated by reference herein, for more information.

Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved