Alliant Energy Corp SEC Filings

Wisconsin Power and Light Company, a subsidiary of Alliant Energy Corporation, agreed to sell $300,000,000 of 5.700% Debentures due 2055 in a public offering. The debentures are being sold to a group of underwriters led by Mizuho Securities USA, Wells Fargo Securities, BofA Securities and MUFG Securities Americas under an underwriting agreement signed on December 2, 2025.

The debentures are issued under an existing indenture with U.S. Bank Trust Company and are registered on an automatic shelf registration statement on Form S-3, supported by a prospectus supplement filed on December 2, 2025. The offering is expected to close on December 5, 2025, subject to standard closing conditions. WPL also filed related exhibits, including the underwriting agreement, the officers’ certificate defining the debenture terms, a legal opinion from Perkins Coie LLP on the validity of the debentures, and a press release announcing that the offering was priced.

Alliant Energy (LNT) filed its Q3 2025 10‑Q, showing higher sales but mixed earnings. For the quarter, total revenues were $1,210 million versus $1,081 million a year ago, while diluted EPS was $1.09 versus $1.15. For the nine months, revenues reached $3,298 million versus $3,005 million and diluted EPS was $2.59 versus $2.10, reflecting stronger year‑to‑date results.

The company highlighted key regulatory developments. The PSCW issued an oral decision approving a settlement that provides WPL a full return of and on approximately $205 million of higher construction costs tied to ~1,100 MW of solar; management concluded no probable disallowance as of September 30, 2025. WPL also no longer considers Columbia Units 1 and 2 (net book value $398 million) probable of abandonment and is evaluating potential natural gas conversion.

Liquidity remained solid. Cash and cash equivalents were $503 million (from $81 million at year‑end), with $250 million in short‑term investments. Year‑to‑date, the company issued $2,174 million of long‑term debt and invested $1,487 million in the utility business. Alliant recognized $117 million of proceeds from renewable tax credits transferred to other corporate taxpayers year‑to‑date.

Alliant Energy Corporation filed a Form 8-K to report quarterly results. On November 6, 2025, the company announced financial results for the three and nine months ended September 30, 2025, and furnished the related press release as Exhibit 99.1.

This is a combined filing for Alliant Energy Corporation, Interstate Power & Light Company, and Wisconsin Power & Light Company. The 8-K lists Item 2.02 (Results of Operations and Financial Condition) and includes the press release under Item 9.01(d).

Alliant Energy Corp (LNT) disclosed an insider equity transaction. A company director reported acquiring 802.583 deferred common stock units on 10/10/2025 (transaction code A).

These units are to be settled in shares of common stock upon the director’s termination of board service. Following the transaction, the reporting person beneficially owned 29,363.427 derivative securities, held directly. The filing notes adjustments for accrued dividends pursuant to a dividend reinvestment transaction exempt under Rule 16a-11.

Alliant Energy (LNT): A company director reported acquiring 915.13 deferred common stock units on 10/10/2025. These units are to be settled in shares of common stock upon the director’s termination of service. Following the transaction, the director beneficially owns 23,541.096 derivative securities. The filing notes adjustments for accrued dividends through a dividend reinvestment transaction exempt under Rule 16a-11.

Alliant Energy (LNT) director reported an acquisition of derivative securities. On 10/10/2025, the reporting person acquired 1,088.561 deferred common stock units (Transaction Code A). Following this transaction, the reporting person beneficially owned 6,266.648 derivative securities, held as Direct ownership.

The units are to be settled in shares of common stock upon the director’s termination of service. The filing notes adjustments for accrued dividends pursuant to a dividend reinvestment transaction exempt under Rule 16a-11.

Alliant Energy (LNT) reported a director’s acquisition of 871.771 deferred common stock units on 10/10/2025, coded as A in a Form 4.

The deferred units have a $0 conversion/exercise price and are to be settled in shares of common stock upon the director’s termination of service. The filing lists a $67.75 price for the derivative security on the transaction date. Following this transaction, the director beneficially owns 17,704.737 deferred common stock units.

Alliant Energy (LNT) reported a director transaction on 10/10/2025. The reporting person acquired 1,070.111 deferred common stock units (Transaction Code: A) in Table II of the filing. The units have a conversion/exercise price of $0 and are designed to be settled in shares of common stock upon the director’s termination of service, per the footnotes.

Following the transaction, the director beneficially owned 15,848.184 derivative securities directly. Footnotes state that amounts include adjustments for accrued dividends through a dividend reinvestment transaction exempt under Rule 16a-11.

Alliant Energy (LNT) disclosed a Form 4 for a director reflecting an acquisition of 695.572 Deferred Common Stock Units on 10/10/2025 (transaction code A). Following the transaction, the reporting person beneficially owns 8,674.605 derivative securities, held directly.

The units are to be settled in shares of common stock upon the director’s termination of service. The filing notes the total includes adjustments for accrued dividends pursuant to a dividend reinvestment transaction exempt under Rule 16a-11.