ALLIANT ENERGY CORP

Alliant Energy is a regulated investor-owned public utility holding company based in Madison, Wisconsin. The company primarily provides regulated electric and natural gas services in the Midwest through its two public utility subsidiaries, IPL and WPL. Alliant Energy serves approximately 1,010,000 electric and approximately 435,000 natural gas customers. IPL, a wholly-owned subsidiary, is a public utility that generates and distributes electricity and distributes and transports natural gas to retail customers in select markets in Iowa. At December 31, 2025, IPL supplied electric and natural gas service to approximately 505,000 and 230,000 retail customers, respectively, in Iowa. IPL also sells electricity to wholesale customers in Illinois and Iowa. Until December 31, 2025, IPL was involved in the generation and distribution of steam for two customers in Cedar Rapids, Iowa, under contracts through 2025 for minimum annual steam usage. Subsequent to December 31, 2025, IPL exited the steam business. WPL, another wholly-owned subsidiary, is a public utility that generates and distributes electricity and distributes and transports natural gas to retail customers in select markets in Wisconsin. At December 31, 2025, WPL supplied electric and natural gas service to approximately 505,000 and 205,000 retail customers, respectively. WPL also sells electricity to wholesale customers in Wisconsin. The CORPORATE SERVICES segment provides administrative services to Alliant Energy, IPL, WPL, and AEF.