Alliant Energy 8-K Report, Corporate Update (May 19, 2025)

Interstate Power and Light Company (IPL), a wholly owned subsidiary of Alliant Energy Corporation (NASDAQ: LNT), filed this Form 8-K on May 19, 2025 to report the public offering of $600 million^a aggregate principal amount of 5.600% Senior Debentures due 2035.

The underwriting agreement was entered into on May 13, 2025 with BofA Securities, Inc., Mizuho Securities USA LLC, MUFG Securities Americas Inc., and Wells Fargo Securities, LLC as representatives of the underwriters. The offering was expected to close on May 19, 2025, subject to standard closing conditions. The debentures are being issued under an existing 2003 indenture with The Bank of New York Mellon Trust Company, N.A., as successor trustee, and are registered under an automatic shelf registration statement on Form S-3.

According to the accompanying press release, IPL intends to use the net proceeds to retire its $50 million^b 5.50% senior debentures maturing July 15, 2025 and its $250 million 3.40% senior debentures maturing August 15, 2025, each at or prior to maturity. Proceeds may also be used to reduce outstanding capital under its receivables purchase and sale program, to reduce outstanding commercial paper, and/or for general corporate purposes. The debentures are due June 29, 2035.

The filing is primarily administrative in nature: it files the underwriting agreement, officer's certificate, legal opinions from Perkins Coie LLP and Simmons Perrine Moyer Bergman PLC, and a pricing press release as exhibits to the existing shelf registration statement. For investors, the key item is IPL's new $600 million^c of long-term debt and its plan to refinance near-term maturities and reduce short-term borrowings.