Executive Change

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) July 10, 2024 Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number ALLIANT ENERGY CORP ORATION (a Wisconsin Corporation) 4902 N. Biltmore Lane Madison , Wisconsin 53718 Telephone ( 608 ) 458-3311 Commission File Number - 1-9894 IRS Employer Identification Number - 39-1380265 INTERSTATE POWER & LIGHT CO MPANY (an Iowa corporation) Alliant Energy Tower Cedar Rapids , Iowa 52401 Telephone ( 319 ) 786-4411 Commission File Number - 1-4117 IRS Employer Identification Number - 42-0331370 WISCONSIN POWER & LIGHT CO MPANY (a Wisconsin corporation) 4902 N. Biltmore Lane Madison , Wisconsin 53718 Telephone ( 608 ) 458-3311 Commission File Number - 0-337 IRS Employer Identification Number - 39-0714890 (Former name or former address, if changed since last report.) This combined Form 8-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. 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: Alliant Energy Corporation, Common Stock, $0.01 Par Value , Trading Symbol LNT , Nasdaq Global Select Market 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). Alliant Energy Corporation - Emerging growth company ☐ Interstate Power and Light Company - Emerging growth company ☐ Wisconsin Power and Light Company - 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. Alliant Energy Corporation ☐ Interstate Power and Light Company ☐ Wisconsin Power and Light Company ☐ Item 5.02      Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On July 10, 2024, John O. Larsen, Executive Chairman and Chairman of the Board of Directors of Alliant Energy Corporation (Alliant Energy), Interstate Power and Light Company (IPL) and Wisconsin Power and Light Company (WPL, and together with Alliant Energy and IPL, the Companies), informed the Board of Directors that he plans to retire from his executive position at the Companies effective on or before January 1, 2025. The Board of Directors confirmed him to the position of non-employee Chairman of the Board of the Companies effective upon his executive retirement. As non-employee Chairman of the Board, Mr. Larsen will receive compensation as a non-employee director in accordance with the non-employee director compensation practices described in Alliant Energy’s Definitive Proxy Statement filed with the Securities and Exchange Commission on April 2, 2024. He will also receive an additional supplemental annual cash retainer of $200,000 for his role as Board Chairman. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company have each duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ALLIANT ENERGY CORPORATION Date: July 15, 2024 By: /s/ Omar N. Chaudhary Omar N. Chaudhary Corporate Secretary INTERSTATE POWER AND LIGHT COMPANY Date: July 15, 2024 By: /s/ Omar N. Chaudhary Omar N. Chaudhary Corporate Secretary WISCONSIN POWER AND LIGHT COMPANY Date: July 15, 2024 By: /s/ Omar N. Chaudhary Omar N. Chaudhary Corporate Secretary