Alliant Energy Files 8-K with Financial Updates

TL;DR

Alliant Energy (LNT) filed an 8-K on 12/5 for events on 12/2, check financials.

AI Summary

Alliant Energy Corp. (through its subsidiary Wisconsin Power & Light Co.) filed an 8-K on December 5, 2025, reporting other events and financial statements/exhibits as of December 2, 2025. The filing includes information related to the company's structure, including its former names like WPL Holdings Inc. and Interstate Energy Corp.

Why It Matters

This 8-K filing provides updated corporate information and financial reporting for Alliant Energy Corp. and its subsidiary, Wisconsin Power & Light Co., which is important for investors tracking the company's status.

Risk Assessment

Risk Level: low — This filing is a routine 8-K reporting other events and financial statements, not indicating any immediate material adverse changes.

Key Numbers

• 20251202 — Report Date (The date as of which the report's information is relevant.)
• 20251205 — Filing Date (The date the 8-K was officially filed with the SEC.)

Key Players & Entities

• ALLIANT ENERGY CORP (company) — Filer
• WISCONSIN POWER & LIGHT CO (company) — Subsidiary Filer
• INTERSTATE ENERGY CORP (company) — Former Company Name
• WPL HOLDINGS INC (company) — Former Company Name
• 0000352541-25-000085 (accession_number) — Filing Accession Number

FAQ

Key Financial Figures

• $0.01 — liant Energy Corporation, Common Stock, $0.01 Par Value , Trading Symbol LNT , Nasdaq
• $300,000,000 — terms and conditions set forth therein, $300,000,000 aggregate principal amount of WPL's 5.7

Filing Documents

• lnt-20251202.htm (8-K) — 38KB
• lnt120220258-kex11.htm (EX-1.1) — 332KB
• lnt120220258-kex41.htm (EX-4.1) — 57KB
• lnt120220258-kex51.htm (EX-5.1) — 13KB
• lnt120220258-kex991.htm (EX-99.1) — 9KB
• imagea.jpg (GRAPHIC) — 42KB
• pcheadera.jpg (GRAPHIC) — 12KB
• 0000352541-25-000085.txt ( ) — 745KB
• lnt-20251202.xsd (EX-101.SCH) — 3KB
• lnt-20251202_def.xml (EX-101.DEF) — 14KB
• lnt-20251202_lab.xml (EX-101.LAB) — 26KB
• lnt-20251202_pre.xml (EX-101.PRE) — 15KB
• lnt-20251202_htm.xml (XML) — 4KB

01 Other Events

Item 8.01 Other Events. On December 2, 2025, Wisconsin Power and Light Company ("WPL"), a subsidiary of Alliant Energy Corporation, entered into an Underwriting Agreement (the "Underwriting Agreement") with Mizuho Securities USA LLC, Wells Fargo Securities, LLC, BofA Securities, Inc. and MUFG Securities Americas Inc., as representatives of the several underwriters listed therein (the "Underwriters"), pursuant to which WPL agreed to sell, and the Underwriters agreed to purchase, subject to the terms and conditions set forth therein, $300,000,000 aggregate principal amount of WPL's 5.700% Debentures due 2055 (the "Debentures"), in a public offering (the "Offering"). The Debentures are to be issued under an Indenture dated as of June 20, 1997, between WPL and U.S. Bank Trust Company, National Association, as successor trustee (the "Trustee"), pursuant to an Officers' Certificate provided pursuant to the Indenture setting forth the terms of the Debentures (the "Certificate"). The Offering is expected to close, subject to standard closing conditions, on December 5, 2025. The Debentures are registered under the Securities Act of 1933, as amended, pursuant to an automatic shelf registration statement on Form S-3 (Registration No. 333-276062-02) that WPL filed with the Securities and Exchange Commission (the "SEC") on December 15, 2023 (the "Registration Statement"). The Registration Statement was supplemented by a Prospectus Supplement setting forth the terms of the Debentures that WPL filed with the SEC on December 2, 2025. This Current Report on Form 8-K ("Form 8-K") is being filed for the purpose of filing exhibits to the Registration Statement relating to the public offering of the Debentures, and all such exhibits are hereby incorporated into the Registration Statement by reference. The Underwriting Agreement is filed as Exhibit 1.1 to this Form 8-K and the Certificate is filed as Exhibit 4.1 to this Form 8-K. On December 2, 2025, WPL issued a press release an

01 Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits. (d) Exhibits Exhibit No. Description 1.1 Underwriting Agreement, dated December 2 , 202 5 , among Wisconsin Power and Light Company and the underwriters named therein. 4.1 Officers' Certificate creating the 5.700 % Debentures due 20 55 of Wisconsin Power and Light Company. 5.1 Opinion of Perkins Coie LLP, dated December 5 , 202 5 , with respect to the 5.700 % Debentures due 20 55 of Wisconsin Power and Light Company. 23.1 Consent of Perkins Coie LLP (contained in Exhibit 5.1 hereto). 99.1 Press Release of Wisconsin Power and Light Company, dated December 2 , 202 5 . 104 Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURES

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation 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: December 5, 2025 By: /s/ Robert J. Durian Robert J. Durian Executive Vice President and Chief Financial Officer WISCONSIN POWER AND LIGHT COMPANY Date: December 5, 2025 By: /s/ Robert J. Durian Robert J. Durian Executive Vice President and Chief Financial Officer

View Full Filing

View this 8-K filing on SEC EDGAR