X0306 4 2023-02-03 0 0000092122 SOUTHERN CO SO 0001227464 FANNING THOMAS A 30 IVAN ALLEN JR. BLVD. NW ATLANTA GA 30308 0 1 0 0 President, CEO & Chairman Southern Company Common Stock 2023-02-03 4 M 0 21216 0.00 A 803119.774 D Southern Company Common Stock 2023-02-03 4 F 0 9587 67.27 D 793532.774 D Southern Company Common Stock 16193.1234 I By 401(K) Southern Company Common Stock 113617 I By Grantor Retained Annuity Trust Performance Restricted Stock Units 0.00 2023-02-03 4 M 0 19624 0.00 D Southern Company Common Stock 19624 19624 D Shares acquired upon vesting of second 1/3 of performance restricted stock units granted on February 3, 2021. Includes 1,592 accrued dividend equivalent units. Shares withheld to satisfy required state and federal tax withholding requirements. Represents second 1/3 of performance restricted stock units granted on February 3, 2021. The remaining 1/3 of the award will vest in 2024. Each restricted stock unit represents the right to receive, at settlement, one share of common stock. Additional units will be acquired with deemed dividends. Shares will be withheld upon vesting to satisfy tax requirements. /s/ Marcia R. DeMar, Attorney-in-Fact for Thomas A. Fanning 2023-02-07