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Alliant Energy Corporation, together with its subsidiaries Interstate Power and Light Company and Wisconsin Power and Light Company, filed a combined Form 10-Q with the SEC on October 30, 2026, covering the quarterly period ended September 30, 2026.

Key Highlights

  • Shares outstanding: Alliant Energy Corporation reported 259,361,652 shares of common stock ($0.01 par value) outstanding as of September 30, 2026.
  • Subsidiary ownership: Interstate Power and Light Company had 13,370,788 shares outstanding, all held beneficially and of record by Alliant Energy Corporation.
  • Subsidiary ownership: Wisconsin Power and Light Company had 13,236,601 shares outstanding, also all held beneficially and of record by Alliant Energy Corporation.
  • Exchange listing: Alliant Energy Corporation common stock trades on the Nasdaq Global Select Market under the symbol LNT, according to the filing's registered-securities table.
  • Filer status: Alliant Energy Corporation is classified as a large accelerated filer; Interstate Power and Light Company and Wisconsin Power and Light Company are each classified as non-accelerated filers.
  • Combined filing: The report is separately filed by all three registrants, with each of Interstate Power and Light Company and Wisconsin Power and Light Company making representations only as to information relating to itself.

Alliant Energy's Three-Entity Combined Quarterly Report for September 30, 2026

According to the filing, Alliant Energy Corporation (NASDAQ:LNT), a Wisconsin corporation headquartered at 4902 N. Biltmore Lane, Madison, Wisconsin, submitted this combined Form 10-Q for the quarterly period ended September 30, 2026, alongside two of its wholly owned subsidiaries: Interstate Power and Light Company, an Iowa corporation based in Cedar Rapids, Iowa, and Wisconsin Power and Light Company, a Wisconsin corporation. The filing carries Commission File Numbers 1-9894, 1-4117, and 0-337 for the three registrants, respectively.

As of September 30, 2026, the filing disclosed that Alliant Energy Corporation had 259,361,652 shares of common stock outstanding at $0.01 par value. All 13,370,788 shares of Interstate Power and Light Company common stock (at $2.50 par value) and all 13,236,601 shares of Wisconsin Power and Light Company common stock (at $5 par value) were reported as owned beneficially and of record by Alliant Energy Corporation. Each subsidiary registrant, according to the filing, "makes no representation as to information relating to registrants other than itself."

The filing identifies a range of risks and uncertainties that could cause actual results to differ from forward-looking statements. Among the factors cited are IPL's and WPL's ability to obtain adequate and timely rate relief, the impact of IPL's retail electric base rate moratorium, the ability to obtain regulatory approval for construction projects, and the ability to complete construction of generation and energy storage projects by planned in-service dates within cost targets. These statements are the company's own and are subject to its cautionary language, as described in the forward-looking statements section of the filing.

What Was Disclosed

This combined Form 10-Q covers Alliant Energy Corporation and its two utility subsidiaries for the quarter ended September 30, 2026. The filing confirms share counts for all three registrants, exchange listing details, filer classifications, and identifies regulatory and operational risk factors.