Alliant Energy Corporation

Filing receipts

“rider in 2025 17 17 — Timing of WPL’s fuel-related cost recoveries from retail electric customers (25) — (25) Other (primarily due to other changes in working capital) 9 13 3 $119 $77 $49 (a) Refer to the cash flows statements for details of renewable tax credits transferred to other corporate taxpayers during the three months ended March 31, 2026.”

“Alliant Energy’s net income and diluted EPS attributable to Alliant Energy common shareowners for the three months ended March 31 were as follows (dollars in millions, except per share amounts): 2026 2025 Income (Loss) EPS Income (Loss) EPS Utilities and Corporate Services $215 $0.83 $225 $0.87 ATC Holdings 11 0.04 10 0.04 Non-utility and Parent (2) — (22) (0.08) Alliant Energy Consolidated $224 $0.87 $213 $0.83 Alliant Energy’s Utilities and Corporate Services net income decreased by $10 million for the three-month period, primarily due to higher other operation and maintenance, financing and depreciation expenses and the timing of income taxes.”

“Estimated increases (decreases) to operating income from the impacts of temperatures for the three months ended March 31 were as follows (in millions): Electric Gas 2026 2025 Change 2026 2025 Change IPL ($7) ($3) ($4) ($4) ($2) ($2) WPL (3) (3) — (2) (1) (1) Total Alliant Energy ($10) ($6) ($4) ($6) ($3) ($3) Electric Sales for Resale - Alliant Energy’s and IPL’s wholesale sales volumes decreased for the three months ended March 31, 2026, compared to the same period in 2025, primarily due to the expiration of IPL’s wholesale power agreement with Southern Minnesota Energy Cooperative in 2025.”