Alliant Energy LNT

Demand for energy from high usage data centers and other large load growth customers may impact our business - The Our ability to serve significant new commercial or industrial customers on contract rates, including data centers, may require certain regulatory approvals, manage the development and the activities and costs implementation of complex business opportunities related to the construction, acquisition growing demand for data centers may be limited by financial, operational, or contracts for additional regulatory factors. We may enter into agreements requiring significant capital investment in generation capacity and transmission required capacity for large load growth customers before realizing any potential returns. We may not be able to affordably and timely construct generation, or cause transmission companies to affordably and timely construct transmission infrastructure to meet the high demands of such customers could be significant. The inability or delays in obtaining regulatory approvals or securing additional capacity or transmission, due to supply chain risk, operational risk, or other factors, may impact our ability, or the cost, to provide energy to new customers, the contract rates may not fully recover the costs, the contracts may increase counterparty credit risk, and the costs to provide service may be higher than expected. The contract rates for high usage customers are subject to regulatory approvals and our regulatory authorities may change the rates we can charge and the costs that can be recovered. potential load growth from any large load growth customer. A high usage large load growth customer may decide not to take energy, take less energy than anticipated, or not take service on the anticipated schedule, due to changes in business needs, construction delays, technological advances that improve energy efficiency, or other factors, which may result in lower demand for energy than anticipated. The addition of high usage large load growth customers may increase the concentration of sales, and increase revenue and earnings volatility. These factors could negatively We may not be able to adequately protect against the risks inherent in relying on rapid growth within a small number of large customers in a single industry. The inability or delays in obtaining regulatory approvals with acceptable conditions or providing sufficient generation or securing transmission, due to supply chain risk, operational risk, or other factors, may impact our ability, or the cost, to provide energy to new customers. The individual customer rates may not provide sufficient revenues to fully recover the costs, the contracts with large load growth customers may increase counterparty credit risk, and the costs to provide service may be higher than expected. Large load growth customers may not be able to meet obligations in our contracts, including the obligation to pay any termination charges. Additionally, if pipeline expansions needed for new gas‑fired generation are delayed or not approved, we may be unable to meet peak requirements for data center load, increasing market purchases or capacity procurement costs. Any of these circumstances could adversely affect our business, financial condition and condition, results of operations. operations and growth prospects.

Alliant Energy IPL WPL Higher revenue requirements (a)(b) $240 $85 $155 $333 $271 $62 Higher (lower) sales for resale bulk power and other revenues (c) 15 (17) 32 Deferral of incremental solar generation construction costs at WPL in 2024 (Refer to Note 3) 12 — 12 Lower revenues primarily due to 78 34 44 Estimated changes in retail electric fuel-related costs at WPL, and credits on IPL’s customers’ bills related to production tax credits through its fuel-related cost recovery mechanism (Refer to Electric Production Fuel and Purchased Power Expenses Variances below) (a)(b) (142) (42) (100) sales volumes caused by temperatures 45 27 18 Changes in WPL refunds/collections of previous over-/under-collection of retail electric fuel-related costs (offset in electric production fuel and purchased power expenses) (Refer to Note 2) (33) 1(g)) 43 — (33) Estimated changes in sales volumes caused by temperatures (23) (13) (10) Lower revenues at IPL due to credits on customers’ bills through the tax benefit rider in 2024 (partially offset by changes in income taxes) (a) (16) (16) — Lower wholesale revenues at WPL primarily due to lower fuel-related costs and lower sales (13) (1) (12) Lower 43 Higher revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense) (Refer to Note 1(g)) (13) (13) 18 18 — Changes in WPL electric fuel-related costs, net of recoveries (d) 8 — 8 Higher (lower) revenues primarily due to changes in retail electric fuel-related costs (Refer to Electric Production Fuel and Purchased Power Expenses Variances below) 5 (10) 15 Lower revenues at IPL due to credits on customers’ bills related to production tax credits through its fuel-related cost recovery mechanism (offset by changes in income taxes) (a) (122) (122) — (10) Lower revenues at IPL due to credits on customers’ bills through the tax benefit rider (partially offset by changes in income taxes) (a) (36) (36) — Lower revenues at IPL from discontinuation of renewable energy rider in 2024 (a) (24) (24) — Lower wholesale revenues at IPL primarily due to lower sales from the expiration of IPL’s wholesale power agreement with Southern Minnesota Energy Cooperative in 2025 (22) (22) — Other 10 3 7 $27 ($14) $41 (1) 13 (14) $325 $149 $176

The Inflation Reduction Act of 2022 provides the ability to transfer renewable tax credits to other corporate taxpayers. In 2023 and 2024, IPL and WPL have entered into agreements to transfer renewable tax credits from certain wind, solar and energy storage facilities to other corporate taxpayers in exchange for cash. Alliant Energy, IPL and WPL have elected to record transfers of renewable tax credits as part of income taxes, and cash received from the transfer of renewable tax credits is recorded in cash flows from operating activities. For renewable Renewable tax credits subject to future transfer, a valuation allowance is transfer are recorded for the difference between the tax value of the credits and the at expected sales price. realizable value. Renewable tax credits and any related valuation allowances are derecognized when control of the tax credits is transferred to other corporate taxpayers. Beginning October 1, 2024, IPL’s renewable energy rider was discontinued, and production tax credits, excluding production tax credits from the refurbishment of existing wind farms, are credited to IPL’s retail electric customers through its fuel-related cost recovery mechanism. Investment tax credits resulting from IPL’s renewable generation and energy storage projects that are not yet included in base rates may be utilized to offset any revenue deficiency on an annual basis up to IPL’s return on common equity threshold; any remaining investment tax credits, net of the cost of transferability, that are not used to offset any revenue deficiency, will be deferred by IPL and carried forward to offset any potential revenue deficiency in future years. At WPL, pursuant to escrow treatment approved by the PSCW, the difference between actual solar and energy storage renewable tax credits and the amount of renewable tax credits collected from customers as electric revenues is recognized in “Income taxes” in Alliant Energy’s and WPL’s income statements. An offsetting amount is recorded in regulatory assets or regulatory liabilities on Alliant Energy’s and WPL’s balance sheets until reflected in future billings to customers. Refer to Notes 11 and Note 16(d) for further discussion of the transfer of renewable tax credits to other corporate taxpayers, including related valuation allowances and indemnification requirements, respectively. requirements.

Transfers of Renewable Tax Credits - In 2023 and 2024, IPL and WPL have entered into agreements to transfer renewable tax credits from certain wind, solar and energy storage facilities to other corporate taxpayers in exchange for cash. As of December 31, 2024, 2025, IPL and WPL provided indemnifications associated with $193 $333 million and $121 $266 million, respectively, of proceeds for renewable tax credits transferred to other corporate taxpayers in the event of an adverse interpretation of tax law, including whether the related tax credits meet the qualification requirements. Alliant Energy, IPL and WPL believe the likelihood of having to make any material cash payments under these indemnifications is remote.