ALLIANT ENERGY CORP

•In April 2026, IPL entered into an electric service agreement with a customer, who currently expects to build a data center in IPL’s service territory. This electric service agreement includes contracted peak demand of approximately 370 MW. The actual timing and amount of increases in IPL’s load are subject to various factors, including interconnections and actual customer demand, and any executed or future agreements with customers are not expected to result in immediate increases in load.

•In June 2026, the PSCW approved an ICR for a customer who is constructing a data center in WPL’s service territory, subject to certain conditions, including the recognition of demand revenue received prior to WPL’s next retail electric rate review through WPL’s retail electric fuel cost recovery mechanism. Refer to “Rate Matters” for additional information regarding the large load tariff requirements established by the PSCW in connection with its approval of the ICR.

Environmental Matters:

Coal Combustion Residuals (CCR) Rule - In April 2026, the EPA proposed a rule that would significantly reduce the scope of the CCR Rule, which is currently anticipated to be finalized by the end of 2026. Alliant Energy, IPL and WPL continue to evaluate the revised CCR Rule and are unable to predict with certainty the future outcome or impact of these updates, including resolution of ongoing litigation.

Effluent Limitation Guidelines and Standards (ELGs) - In May 2026, the EPA proposed changes to the 2024 ELG Rule, which are currently anticipated to be finalized by the end of 2026. The proposed rule would revise discharge limits for specific categories of wastewater from certain existing steam EGUs. If finalized, the revised limitations would be implemented in the wastewater discharge permits issued by state agencies to affected facilities. Alliant Energy, IPL and WPL continue to evaluate the revised 2024 ELG Rule and are unable to predict with certainty the future outcome or impact of these updates, including resolution of ongoing or potential litigation.

Legislative Matters:

•In April 2026, the State of Wisconsin enacted 2025 Wisconsin Act 193, which requires utilities to include their capacity costs and revenues in their annual fuel cost plans. The most significant provisions of the legislation for Alliant Energy and WPL are the requirement that fuel cost calculations in approved fuel cost plans account for both the cost of purchasing capacity and the revenue generated from selling it. The legislation applies to fuel cost plans filed on or after January 1, 2027.