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) March 15, 2023

Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number

ALLIANT ENERGY CORPORATION

(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 COMPANY

(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 COMPANY

(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 2.03    Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

On March 15, 2023, Alliant Energy Corporation (“Alliant Energy”), Interstate Power and Light Company (“IPL”), a wholly-owned subsidiary of Alliant Energy, and Wisconsin Power and Light Company (“WPL”), a wholly-owned subsidiary of Alliant Energy, entered into an amendment (the “First Amendment”) to the amended and restated five-year master credit agreement (the “Credit Agreement”), dated December 17, 2021, among Alliant Energy, IPL, WPL, Wells Fargo Bank, National Association, as Administrative Agent, and the several lenders party thereto. The First Amendment amended the Credit Agreement to extend the facility termination date from December 17, 2026 to December 17, 2027, adjust the sublimits within the credit facility for each of the three borrowers, revise a cross-default related to prepayment of material debt prior to the stated maturity, replace LIBOR-based benchmark rates with SOFR-based benchmark rates, and make certain other conforming changes.

The amended sublimits for borrowings by Alliant Energy at the parent company level, IPL and WPL are $500 million, $100 million and $400 million, respectively, within the $1 billion total commitment. The cross-default provision was revised to exclude conversions of convertible notes from events that would constitute a cross default.

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: March 16, 2023	By:/s/ Robert J. Durian
	Robert J. Durian
	Executive Vice President and Chief Financial Officer

INTERSTATE POWER AND LIGHT COMPANY

Date: March 16, 2023	By:/s/ Robert J. Durian
	Robert J. Durian
	Executive Vice President and Chief Financial Officer

WISCONSIN POWER AND LIGHT COMPANY

Date: March 16, 2023	By:/s/ Robert J. Durian
	Robert J. Durian
	Executive Vice President and Chief Financial Officer