X0306 4 2021-02-03 0 0000092122 SOUTHERN CO SO 0001538652 Wilson Anthony L 30 IVAN ALLEN JR. BLVD., NW ATLANTA GA 30308 0 1 0 0 Pres & CEO, Mississippi Power Southern Company Common Stock 2021-02-03 4 M 0 1354 0.00 A 36619 D Southern Company Common Stock 2021-02-03 4 F 0 673 59.45 D 35946 D Southern Company Common Stock 19207.61 I By 401(k) Trustee Performance Restricted Stock Units 0.00 2021-02-03 4 M 0 1298 0.00 D Southern Company Common Stock 1298 2594 D Shares acquired upon vesting of first 1/3 of performance restricted stock units granted on February 11, 2020. The Compensation Committee and Management Succession Committee certified performance on February 3, 2021. Includes 56 accrued dividend equivalent units. Shares withheld to satisfy required state and federal tax withholding requirements. Represents performance share units granted on February 11, 2020. The Compensation and Management Succession Committee certified performance on February 3, 2021 and the first 1/3 vested. The remaining award will vest 1/3 in 2022 and 1/3 in 2023. Each performance restricted stock unit represents the right to receive, at statement, 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 Anthony L. Wilson 2021-02-05