X0407 4 2023-06-09 0 0000092122 SOUTHERN CO SO 0001227464 FANNING THOMAS A 30 IVAN ALLEN JR. BLVD. NW ATLANTA GA 30308 1 0 0 0 1 Southern Company Common Stock 2023-06-09 4 S 0 50000 70.76 D 844238.797 D Southern Company Common Stock 17292.1454 I By 401(K) Southern Company Common Stock 66970 I By Grantor Retained Annuity Trust Shares sold pursuant to a 10b5-1 trading plan entered into on February 24, 2023 for estate, financial and tax planning purposes. Plan allows for the sale of up to 150,000 shares from 4/10/2023 through 6/12/2023. After completion of the transactions, Mr. Fanning will continue to hold shares of Southern common stock that significantly exceed his share ownership requirements. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $70.38 to $71.14, inclusive. The reporting person undertakes to provide to Southern Company, any security holder of Southern Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4. /s/ Marcia R. DeMar, Attorney-in-Fact for Thomas A. Fanning 2023-06-12