Alliant Energy Corp SEC Filings

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.

Alliant Energy Corporation entered into an underwriting agreement to sell $725 million aggregate principal amount of 5.750% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2056 in a public offering.

The Notes will be issued under an Indenture with The Bank of New York Mellon Trust Company, N.A., were registered on a Form S-3 shelf registration (No. 333-276062) and described in a prospectus supplement filed September 25, 2025. The underwriting agreement and related indentures and legal and tax opinions are filed as exhibits to this Current Report.

Alliant Energy is offering $725.0 million of Fixed-to-Fixed Reset Rate Junior Subordinated Notes due April 1, 2056. Interest is payable semi-annually on April 1 and October 1 beginning April 1, 2026, and the company has an option to defer interest for up to a 10-year period subject to limitations; deferred interest accrues additional interest at the then-applicable rate. As of June 30, 2025, Alliant Energy reported $11,015 million of consolidated indebtedness (net of certain adjustments) and, after giving effect to this offering, consolidated indebtedness would be $11,740 million. The notes will be junior subordinated debt, ranking equally with any future junior subordinated indebtedness but effectively subordinated to any secured or senior unsecured indebtedness and to liabilities of its subsidiaries (subsidiary indebtedness and other liabilities were reported at $15,472 million as of June 30, 2025). The prospectus discusses tax treatment expectations (treated as variable rate debt instruments if deferral is deemed remote) and withholding/FATCA considerations for Non-U.S. Holders.

Alliant Energy is offering fixed-to-fixed reset rate junior subordinated notes described in this prospectus supplement. The notes permit the company to optionally defer interest payments (subject to specified timing and restrictions), and any deferred interest will accrue additional interest at the then-applicable rate to the extent permitted by law. As of June 30, 2025, Alliant Energy reported $11,015 million of consolidated indebtedness (net of unamortized costs), no secured debt, and $550 million of undrawn capacity under its single revolving credit facility. Its subsidiaries had approximately $15,472 million of indebtedness and other liabilities to third parties to which the notes would be structurally subordinated. After giving effect to the issuance and use of proceeds, consolidated indebtedness would have been $11,740 million. The company expects the notes to be treated as variable rate debt instruments for U.S. federal income tax purposes but warns that if the deferral option is not considered remote or is exercised, the notes could be treated as issued with original issue discount, with related tax consequences for U.S. holders.