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 October 2026, IPL filed a request with the IUC for approval of an ICR for a data center expected to be constructed in its service territory. A decision from the IUC is currently expected in the first quarter of 2027.

•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.

Clean Air Act Section 111(d) - In September 2026, the EPA finalized a rule repealing the Section 111(d) emission guidelines for existing fossil-fueled EGUs, which would have imposed compliance requirements beginning in 2030 for certain affected Alliant Energy, IPL and WPL generating facilities through measures such as retirement, enforceable limits on operations, co-firing with low-GHG fuels or carbon capture and storage technology. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing or potential litigation.

Clean Air Act Section 111(b) - In September 2026, the EPA finalized a rule partially repealing the 2024 revised standards under Section 111(b), which established carbon dioxide (CO2) emission limits from certain new and reconstructed fossil-fueled EGU combustion turbines that commence operation after May 23, 2023 with a capacity greater than 25 MW. The partial repeal removes standards based on carbon capture and storage that would have been effective by January 1, 2032. However, standards requiring low-emitting fossil-fuels and highly efficient EGU design technology with best operation and maintenance practices remain in effect for certain newly constructed fossil-fueled EGUs. The EPA also issued a supplemental proposal that would rescind the greenhouse gas findings for fossil-fueled EGUs and repeal the remaining CO2 regulations for fossil-fueled EGUs under Section 111 of the Clean Air Act. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, 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.

•In October 2026, legislation was enacted revising the Major Economic Growth Attraction program in Iowa for projects located in rural counties. The legislation allows the Iowa Economic Development Authority to provide either an investment tax credit of up to 10% of a qualifying investment for a project located in a rural county or investment tax credits of up to 5% of qualifying investments for up to two projects. The most significant provision of this program for Alliant Energy encourages economic development in IPL’s service territory by supporting certain projects with capital investments greater than $1 billion and may support the development of certain large load growth projects, including the proposed construction of a steel plant in Southeast Iowa.

Financings and Common Stock Dividends:

•Refer to “Results of Operations” for discussion of expected future issuances of common stock in 2026 through 2030 and common stock dividends in 2027, and expected future issuances and retirements of long-term debt by the end of 2027.

•In October 2026, IPL and WPL entered into loan guarantee agreements with the U.S. Department of Energy (DOE), who may guarantee borrowings of up to $3.5 billion and $1.6 billion, respectively. Refer to “U.S. Department of Energy Loan Guarantee Borrowings” in Liqui dity and Capital Resources for further details.