SOUTHERN CO (SO) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-07-01 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: SOUTHERN CO (SO) CIK: 0000092122 --- Reporting Owner --- Name: SMITH WILLIAM G JR CIK: 0000909019 Role: Director --- Derivative Transactions --- [Transaction #1] Security: Deferred Stock Units Holding Date: 2026-07-01 | Code: A (Grant or award) Shares: +867.3255 | Price: $95.12 Shares Owned After: 163,012.5325 | Ownership: D (Direct) Footnotes: [F1] Represents quarterly director cash and equity retainers paid under the Southern Company 2021 Equity and Incentive Compensation Plan and deferred pursuant to the Deferred Compensation Plan for Outside Directors of The Southern Company (Deferred Compensation Plan). Each deferred stock unit represents the right to receive one share of Southern Company common stock. [F2] Deferred stock units are settled in shares of Southern Company common stock on the date(s) following the termination of the reporting person's service on the Board as specified by the reporting person pursuant to the Deferred Compensation Plan. There is no exercise or expiration date. [F2] Deferred stock units are settled in shares of Southern Company common stock on the date(s) following the termination of the reporting person's service on the Board as specified by the reporting person pursuant to the Deferred Compensation Plan. There is no exercise or expiration date. [F3] Includes additional deferred stock units acquired through the dividend reinvestment feature of the Deferred Compensation Plan. --- Footnotes (Complete Index) --- F1: Represents quarterly director cash and equity retainers paid under the Southern Company 2021 Equity and Incentive Compensation Plan and deferred pursuant to the Deferred Compensation Plan for Outside Directors of The Southern Company (Deferred Compensation Plan). Each deferred stock unit represents the right to receive one share of Southern Company common stock. F2: Deferred stock units are settled in shares of Southern Company common stock on the date(s) following the termination of the reporting person's service on the Board as specified by the reporting person pursuant to the Deferred Compensation Plan. There is no exercise or expiration date. F3: Includes additional deferred stock units acquired through the dividend reinvestment feature of the Deferred Compensation Plan. --- Signature --- /s/ /s/ Brittney Anderson, Attorney-in-Fact for William G. Smith, Jr. (2026-07-02)