Shareholder Vote

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D. C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 13, 2026 Commission File Number Registrant, State of Incorporation, Address and Telephone Number I.R.S. Employer Identification No. 1-3526 The Southern Company 58-0690070 (A Delaware Corporation) 30 Ivan Allen Jr. Boulevard, N.W . Atlanta , Georgia 30308 ( 404 ) 506-5000 The name and address of the registrant have not changed since the last report. Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Registrant Title of each class Trading Symbol(s) Name of each exchange on which registered The Southern Company Common Stock, par value $5 per share SO New York Stock Exchange The Southern Company Series 2017B 5.25% Junior Subordinated Notes due 2077 SOJC New York Stock Exchange The Southern Company Series 2020A 4.95% Junior Subordinated Notes due 2080 SOJD New York Stock Exchange The Southern Company Series 2020C 4.20% Junior Subordinated Notes due 2060 SOJE New York Stock Exchange The Southern Company Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081 SO 81 New York Stock Exchange The Southern Company Series 2025A 6.50% Junior Subordinated Notes due 2085 SOJF New York Stock Exchange The Southern Company 2025 Series A Corporate Units SOMN New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company   ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.   ☐ Item 5.07. Submission of Matters to a Vote of Security Holders. The Southern Company (the “Company”) held its Annual Meeting of Stockholders on May 13, 2026. Stockholders voted as follows on the ten matters presented for a vote: 1. The nominees for election to the Board of Directors were elected based on the following votes: Nominees Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes Janaki Akella 784,876,449 98.68  % 10,432,453 2,053,270 179,338,232  Shantella E. Cooper 783,342,955 98.49  % 11,966,881 2,052,336 179,338,232  Anthony F. Earley, Jr. 778,970,288 97.94  % 16,310,213 2,081,671 179,338,232  James O. Etheredge 787,103,009 98.97  % 8,171,485 2,087,678 179,338,232  David J. Grain 771,268,167 96.98  % 24,003,646 2,090,359 179,338,232  John D. Johns 782,392,634 98.38  % 12,882,396 2,087,142 179,338,232  David E. Meador 780,239,348 98.10  % 15,074,948 2,047,876 179,338,232  William G. Smith, Jr. 772,562,017 97.14  % 22,714,125 2,086,030 179,338,232  Kristine L. Svinicki 779,969,354 98.06  % 15,380,351 2,012,467 179,338,232  Lizanne Thomas 774,256,082 97.34  % 21,142,031 1,964,059 179,338,232  John M. Turner, Jr. 787,367,826 99.00  % 7,923,303 2,071,043 179,338,232  Christopher C. Womack 773,084,318 97.20  % 22,205,419 2,072,435 179,338,232  2. The proposal to approve, on an advisory basis, the Company’s named executive officers’ compensation was approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 754,894,258 95.24  % 37,651,570 4,816,344 179,338,232 3. The proposal to ratify the appointment of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for 2026 was approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 947,424,572 97.24  % 26,799,479 2,476,353 N/A 4. The proposal to approve an amendment to the Company’s Restated Certificate of Incorporation to authorize additional common stock was approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 946,532,072 97.39  % 25,346,091  4,822,241  N/A 5. The proposal to approve an amendment to the Company’s Restated Certificate of Incorporation to authorize the issuance of preferred stock was approved based upon the following votes: Votes For % Outstanding For Votes Against Abstentions Broker Non-Votes 733,634,497 65.07  % 60,516,566 3,211,109 179,338,232   6. The proposal to approve an amendment to the Company’s Restated Certificate of Incorporation to provide for officer exculpation was approved based upon the following votes: Votes For % Outstanding For Votes Against Abstentions Broker Non-Votes 686,673,476 60.91  % 106,098,507 4,590,189 179,338,232 7. The proposal to approve miscellaneous amendments to the Company’s Restated Certificate of Incorporation to modernize, clarify and conform the Company’s Restated Certificate of Incorporation was approved based upon the following votes: Votes For % Outstanding For Votes Against Abstentions Broker Non-Votes 788,336,975 69.93  % 5,357,089 3,668,108 179,338,232 8. The stockholder proposal regarding an independent board chairman was not approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 103,219,771 13.06  % 686,754,673 7,387,728 179,338,232 2 9. The stockholder proposal regarding a report on data center costs was not approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 76,742,427 9.74  % 710,841,526 9,778,219 179,338,232 10. The stockholder proposal regarding a report on climate due diligence was not approved based upon the following votes: Votes For % Votes Cast For Votes Against Abstentions Broker Non-Votes 9,987,213 1.26  % 777,636,402 9,738,557 179,338,232 Item 9.01. Financial Statements and Exhibits .  (d) Exhibits.   3.1 Certificate of Amendment of Restated Certificate of Incorporation of the Company, effective May 13 , 2026 .   3.2 R estated Certificate of Incorporation of the Company, dated May 13 , 2026.   104 Cover Page Interactive Data File – The cover page iXBRL tags are embedded within the inline XBRL document. 3 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date:   May 15, 2026 THE SOUTHERN COMPANY By /s/Melissa K. Caen Melissa K. Caen Assistant Secretary 4