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10-K – 2026-02-20 – lnt-20251231.htm
Financial Transmission Rights and Auction Revenue Rights - In areas of constrained transmission capacity, energy costs could be higher due to congestion and its impact on locational marginal prices. FTRs provide a hedge for certain congestion costs that occur in the MISO energy market. MISO allocates auction revenue rights to IPL and WPL annually based on a fiscal year from June 1 through May 31 and historical use of the transmission system. The allocated auction revenue rights are used by IPL and WPL to acquire FTRs through the FTR auctions operated by MISO. Resource Adequacy - MISO has resource adequacy requirements to help ensure adequate resources to meet forecasted peak load obligations plus a reserve margin. Accredited capacity assigned to EGUs is available to meet these requirements. In order for an EGU to receive accredited capacity, it must meet MISO capacity accreditation requirements, which can include satisfying transmission requirements identified in its interconnection agreement prior to the MISO planning year. Refer to “ Electric Demand Planning Reserve Margi n ” above for discussion of MISO’s seasonal resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements. 12 Table of Contents Electric Operating Information - Alliant Energy 2025 2024 2023 Revenues (in millions): Residential $1,339 $1,236 $1,220 Commercial 932 821 820 Industrial 1,034 952 968 Retail subtotal 3,305 3,009 3,008 Sales for resale: Wholesale 184 200 213 Bulk power and other 164 86 71 Other 44 77 53 Total $3,697 $3,372 $3,345 Sales (000s MWh): Residential 7,393 7,104 7,176 Commercial 6,492 6,304 6,329 Industrial 11,237 11,161 11,435 Retail subtotal 25,122 24,569 24,940 Sales for resale: Wholesale 2,565 2,783 2,859 Bulk power and other 5,386 5,620 4,730 Other 56 57 58 Total 33,129 33,029 32,587 Customers (End of Period): Retail 1,009,387 1,002,967 995,982 Other 2,899 2,915 2,914 Total 1,012,286 1,005,882 998,896 Other Selected Electric Data: Maximum summer peak hour demand (MW) 5,465 5,638 5,856 Maximum winter peak hour demand (MW) 4,433 4,317 4,240 Cooling degree days (a): Cedar Rapids, Iowa (IPL) (normal - 831) 1,054 890 974 Madison, Wisconsin (WPL) (normal - 716) 755 742 781 Sources of electric energy (000s MWh): Gas 12,440 13,883 14,764 Purchased power: Wind (b) 4,165 4,285 4,067 Other (b) 1,121 1,715 1,883 Wind (b) 5,370 5,540 5,410 Solar (b) 2,811 1,833 471 Coal 7,724 6,204 6,447 Other (b) 191 201 186 Total 33,822 33,661 33,228 Revenue per KWh sold to retail customers (cents) $13.16 $12.25 $12.06 (a) Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days. Refer to “ Gas Operating Information ” below for details of heating degree days. (b) All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements. 13 Table of Contents Electric Operating Information IPL WPL 2025 2024 2023 2025 2024 2023 Revenues (in millions): Residential $661 $640 $641 $678 $596 $579 Commercial 609 525 519 323 296 301 Industrial 531 497 501 503 455 467 Retail subtotal 1,801 1,662 1,661 1,504 1,347 1,347 Sales for resale: Wholesale 39 61 62 145 139 151 Bulk power and other 28 (6) 11 136 92 60 Other 28 30 27 16 47 26 Total $1,896 $1,747 $1,761 $1,801 $1,625 $1,584 Sales (000s MWh): Residential 3,722 3,573 3,586 3,671 3,531 3,590 Commercial 4,095 3,974 3,988 2,397 2,330 2,341 Industrial 6,065 6,073 6,335 5,172 5,088 5,100 Retail subtotal 13,882 13,620 13,909 11,240 10,949 11,031 Sales for resale: Wholesale 481 750 766 2,084 2,033 2,093 Bulk power and other 1,777 1,138 1,465 3,609 4,482 3,265 Other 31 32 32 25 25 26 Total 16,171 15,540 16,172 16,958 17,489 16,415 Customers (End of Period): Retail 505,636 503,279 500,938 503,751 499,688 495,044 Other 865 881 878 2,034 2,034 2,036 Total 506,501 504,160 501,816 505,785 501,722 497,080 Other Selected Electric Data: Maximum summer peak hour demand (MW) 2,759 2,833 2,940 2,735 2,805 2,926 Maximum winter peak hour demand (MW) 2,433 2,359 2,294 2,042 2,034 1,946 Cooling degree days (a): Cedar Rapids, Iowa (IPL) (normal - 831) 1,054 890 974 N/A N/A N/A Madison, Wisconsin (WPL) (normal - 716) N/A N/A N/A 755 742 781 Sources of electric energy (000s MWh): Gas 5,707 5,965 6,636 6,733 7,918 8,128 Purchased power: Wind (b) 2,622 2,681 2,504 1,543 1,604 1,563 Other (b) 493 1,228 730 628 487 1,153 Wind (b) 4,249 4,347 4,257 1,121 1,193 1,153 Solar (b) 740 119 11 2,071 1,714 460 Coal 2,577 1,442 2,252 5,147 4,762 4,195 Other (b) 1 — 1 190 201 185 Total 16,389 15,782 16,391 17,433 17,879 16,837 Revenue per KWh sold to retail customers (cents) $12.97 $12.20 $11.94 $13.38 $12.30 $12.21 (a) Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days. Refer to “ Gas Operating Information ” below for details of heating degree days. (b) All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements. 14 Table of Contents 2) GAS UTILITY OPERATIONS General - Alliant Energy’s gas utility operations are located in the Midwest with IPL providing gas service in Iowa and WPL providing gas service in Wisconsin. Refer to the “ Gas Operating Information ” tables for additional details regarding gas utility operations. Refer to Not e 1(g) for information relating to utility natural gas cost recovery mechanisms and Note 1 6 (b) for discussion of natural gas commitments. Customers - IPL and WPL provide gas utility service to a large base of retail customers and industries, including research, education, hospitality, manufacturing and chemicals (including ethanol). In addition, IPL and WPL provide transportation service to commercial and industrial customers by moving customer-owned gas through Alliant Energy’s distribution systems to the customers’ meters. Seasonality - Gas sales follow a seasonal pattern with an annual base-load of gas and a large heating peak occurring during the winter season. Natural gas obtained from producers, marketers and brokers, as well as gas in storage, is utilized to meet the peak heating season requirements. Storage contracts generally allow IPL and WPL to purchase gas in the summer and inject it into underground storage fields, and remove it from storage fields in the winter to deliver to customers. Competition - Gas customers in Iowa and Wisconsin currently do not have the ability to choose their gas distributor, and IPL and WPL have obligations to serve all their gas customers. While the gas utility distribution function is expected to remain a regulated function, sales of the natural gas commodity and related services are subject to competition from third-parties who provide alternative fuel sources (e.g. propane). However, when natural gas service is available for a given area, customers in such area have generally selected natural gas over propane as a more cost competitive solution for their fuel needs. Refer to “ Customer Investments ” in MDA for discussion of plans to expand gas distribution systems. Gas Supply - IPL and WPL maintain purchase agreements with numerous suppliers of natural gas from various gas producing regions of the U.S. and Canada. In providing gas commodity service to retail customers, Corporate Services administers a portfolio of transportation and storage contracts on behalf of IPL and WPL. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates for the cost of gas sold to these customers. As a result, natural gas prices do not have a material impact on IPL’s or WPL’s operating income. Gas Demand Planning Reserve Margin - IPL and WPL are required to maintain adequate pipeline capacity to ensure they meet their customers’ maximum daily system demand requirements. IPL and WPL currently have planning reserve margins of 2% and 1%, respectively, above their forecasted maximum daily system demand requirements from November 2025 through March 2026. Gas Operating Information - Alliant Energy 2025 2024 2023 Revenues (in millions): Residential $306 $275 $316 Commercial 153 133 163 Industrial 13 11 16 Retail subtotal 472 419 495 Transportation/other 53 46 45 Total $525 $465 $540 Sales (000s Dths): Residential 27,945 24,243 25,838 Commercial 19,264 16,974 18,291 Industrial 2,154 2,272 2,276 Retail subtotal 49,363 43,489 46,405 Transportation/other 123,141 123,386 115,177 Total 172,504 166,875 161,582 Retail Customers (End of Period) 433,344 430,699 428,143 Other Selected Gas Data: Heating degree days (a): Cedar Rapids, Iowa (IPL) (normal - 6,684) 6,215 5,450 5,807 Madison, Wisconsin (WPL) (normal - 6,929) 6,841 5,801 6,157 Revenue per Dth sold to retail customers $9.56 $9.63 $10.67 Purchased gas costs per Dth sold to retail customers $5.24 $5.06 $6.37 15 Table of Contents Gas Operating Information IPL WPL 2025 2024 2023 2025 2024 2023 Revenues (in millions): Residential $155 $148 $176 $151 $127 $140 Commercial 72 68 86 81 65 77 Industrial 7 7 11 6 4 5 Retail subtotal 234 223 273 238 196 222 Transportation/other 31 27 27 22 19 18 Total $265 $250 $300 $260 $215 $240 Sales (000s Dths): Residential 14,026 12,413 13,146 13,919 11,830 12,692 Commercial 8,427 7,714 8,477 10,837 9,260 9,814 Industrial 1,257 1,513 1,505 897 759 771 Retail subtotal 23,710 21,640 23,128 25,653 21,849 23,277 Transportation/other 44,489 43,075 43,232 78,652 80,311 71,945 Total 68,199 64,715 66,360 104,305 102,160 95,222 Retail Customers (End of Period) 227,345 226,838 226,265 205,999 203,861 201,878 Other Selected Gas Data: Maximum daily winter peak demand (Dth) 266,886 267,820 290,922 250,286 221,135 234,796 Heating degree days (a): Cedar Rapids, Iowa (IPL) (normal - 6,684) 6,215 5,450 5,807 N/A N/A N/A Madison, Wisconsin (WPL) (normal - 6,929) N/A N/A N/A 6,841 5,801 6,157 Revenue per Dth sold to retail customers $9.87 $10.30 $11.80 $9.28 $8.97 $9.54 Purchased gas cost per Dth sold to retail customers $5.51 $5.68 $7.16 $4.98 $4.44 $5.59 (a) Heating degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical heating degree days. 3) OTHER UTILITY OPERATIONS - STEAM - IPL’s Prairie Creek facility provided steam for IPL’s two high-pressure steam customers in Iowa. These customers were each under contract through 2025 for taking minimum quantities of annual steam usage, with certain conditions. Subsequent to December 31, 2025, IPL exited the steam business. ITEM 1A. RISK FACTORS You should carefully consider each of the risks described below relating to Alliant Energy, IPL and WPL, together with all of the other information contained in this combined report, before making an investment decision with respect to our securities. If any of the following risks develop into actual events, our business, financial condition or results of operations could be materially and adversely affected, and you may lose all or part of your investment. Risks Related to Data Center and Other Large Load Growth Customers Demand from data centers and other large load growth customers may impact our business - Our ability to manage the development and implementation of complex business opportunities related to the growing demand for data centers may be limited by financial, operational, or regulatory factors. We may enter into agreements requiring significant capital investment in generation and transmission 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 potential load growth from any large load growth customer. A 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 large load growth customers may increase the concentration of sales, and increase revenue and earnings volatility. 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, results of operations and growth prospects. 16 Table of Contents Laws, regulations, and opposition to data centers may impact our business - Federal, state or local legislation, rulemaking, or siting standards that specifically restrict or delay the zoning, siting or operation of data centers could reduce or defer expected load growth and impair cost recovery for associated infrastructure. Community opposition to data centers—driven by concerns about land use, water consumption, generation emissions, noise, or traffic—could result in permitting delays, litigation, project cancellations, or additional mitigation costs, reducing expected load growth. The ability to serve significant new commercial or industrial customers on contract rates, including data centers, may require certain regulatory approvals, and the activities and costs related to the construction, acquisition or contracts for additional generation capacity and transmission required to meet the high demands of such customers could be significant. The individual customer rates for large load growth customers are subject to regulatory approvals and our regulatory authorities may change the rates we can charge and the costs that can be recovered. As a result, we may experience adverse impacts on our financial condition and results of operations. Risks Related to Laws and Regulations Our utility business is significantly impacted by government legislation, regulation and oversight - Our utility financial condition is influenced by how regulatory authorities, including the IUC, the PSCW and FERC, establish the rates we can charge our customers, our authorized rates of return and common equity levels, and the costs that may be recovered from customers. Our ability to timely obtain rate adjustments to earn authorized rates of return depends upon timely regulatory action under applicable statutes and regulations, and cannot be guaranteed. IPL and WPL may not receive an adequate amount of rate relief to recover all costs and earn their authorized rates of return, rates may be reduced, rate refunds may be required, rate adjustments may not be approved on a timely basis, costs may not be otherwise recovered through rates, earnings above certain thresholds may be required to be refunded or be used to reduce existing rate base of assets with higher levels of authorized return on equity, recovery of capital expenditures, including those for electric distribution systems, above certain thresholds may be capped or not be allowed, rates may be temporarily frozen, such as IPL’s current retail electric rate base moratorium through September 2029, laws, rules or settlements may limit the ability to file rate adjustments or the period covered by a rate adjustment, regulatory decisions may limit the ability to defer recovery of and a return on prudently incurred costs in between rate reviews, certain rate base items may not receive a full weighted average cost of capital, and authorized rates of return on capital may be reduced. As a result, we may experience adverse impacts on our financial condition and results of operations. In addition, our operations are subject to extensive regulation primarily by the IUC, the PSCW and FERC. We are also subject to oversight and monitoring by organizations such as the North American Electric Reliability Corporation, the Midwest Reliability Organization, the Pipeline and Hazardous Materials Safety Administration, the Midcontinent Independent System Operator, Inc. (MISO) and the Department of Homeland Security Transportation Security Administration. The impacts on our operations include: our ability to site and construct new energy facilities, such as renewable energy, energy storage projects, or natural gas-fired electric generating units (EGUs), and recover associated costs; our ability to decommission generating facilities and recover related costs and the remaining carrying value of these facilities and related assets; MISO’s resource adequacy process establishing seasonal capacity planning reserve margin and capacity accreditation requirements, as well as additional changes to capacity accreditation, such as the direct loss of load methodology, impact how and when existing and new generating facilities such as IPL’s and WPL’s additional solar generation are accredited with energy capacity, and may require IPL and WPL to adjust their current resource plans, to add resources to meet the requirements of MISO’s seasonal resource adequacy process, or procure capacity whereby such costs might not be recovered in rates; legislation or regulation that imposes mandatory integrated resource planning requirements, or materially changes existing resource planning standards, could delay approvals, require revisions to resource plans, increase compliance costs, and impact our ability to timely meet demand for energy from commercial and industrial customers, including data centers; the impact of the lack of availability of existing and new generating facilities on our accredited capacity for such facilities pursuant to MISO’s seasonal resource adequacy process; IPL’s ability to achieve certain aggregate summer capacity factors under the consumer protection plan for its up to 400 MW of solar generation projects; the rates paid to transmission operators and how those costs are recovered from customers, including our ability to continue to use a transmission rider in Iowa; our ability to site, construct and recover costs for new natural gas pipelines; our ability to recover costs to upgrade our electric and gas distribution systems; the amount of certain sources of energy we must use, such as renewable sources; our ability to purchase generating facilities and recover the costs associated therewith; our ability to sell utility assets and any conditions placed upon the sale of such assets; our ability to enter into purchased power agreements and recover the costs associated therewith; the allocation of expenditures by transmission companies on transmission network upgrades and our ability to recover costs associated therewith; reliability; safety; the issuance of securities and ability to use other financing arrangements for our renewable energy projects; accounting matters; and transactions between affiliates. These regulatory authorities and organizations are also empowered to impose financial penalties and other sanctions, including requirements to implement new compliance programs. Failure to obtain approvals for any of these matters in a timely manner, or receipt of approvals with uneconomical conditions, may cause us not to pursue the construction of such projects, or to record an impairment of our assets, or may cause a delay in construction of such projects such that we are not able to meet new demand growth, and may have a material adverse impact on our financial condition and results of operations. Legislative or regulatory changes that enable large load growth customers, including data centers, to own or procure on-site generation or to self-supply through sources behind-the-meter or behind-the-meter arrangements could materially reduce retail sales, shift cost recovery to remaining customers, and impact our ability to earn authorized rates of return. Changes to these regulations could materially increase our costs or cause us to reconsider our strategy, which could have a material adverse impact on our financial condition and results of operations. 17 Table of Contents Provisions of the Wisconsin Utility Holding Company Act may limit our ability to invest in or grow our non-utility activities and may deter potential purchasers who might be willing to pay a premium for our stock. Our utility businesses are subject to numerous environmental laws and regulations - Our utilities are subject to numerous federal, regional, state and local environmental laws, regulations, court orders, and international treaties. These laws, regulations and court orders generally concern emissions into the air, discharges into water, use of water, wetlands preservation, remediation of contamination, waste disposal and containment, disposal of coal combustion residuals, hazardous waste disposal, threatened and endangered species, and noise regulation, among others. Failure to comply with such laws, regulations and court orders, or to obtain or comply with any necessary environmental permits pursuant to such laws and regulations, could result in injunctions, fines or other sanctions. Environmental laws and regulations affecting power generation and electric and gas distribution are complex and subject to continued uncertainty and could be changed by the current or future Presidential or Gubernatorial Administrations. These laws and regulations have imposed, and proposed laws and regulations could impose in the future, additional costs on our utility operations and requirements that impact our ability to continue operating EGUs. We have incurred, and will continue to incur, capital and other expenditures to comply with these and other environmental laws and regulations. Changes in or new development of environmental restrictions may force us to incur significant expenses or expenses that may exceed our estimates. Our future plans and existing operations may be impacted by changing expectations, including environmental and social justice concerns related to renewable energy and a low-carbon economy. There can be no assurance that we would be able to recover all or any increased environmental costs from our customers. Failure to comply with the laws, regulations and court orders, changes in the laws and regulations and failure to recover costs of compliance may adversely impact our financial condition and results of operations. Actions related to global climate change and reducing greenhouse gas (GHG) emissions could negatively impact us - We have established voluntary GHG reduction goals and continue to review our strategy; however, the ability to achieve our voluntary GHG reduction goals and implement our strategy is subject to uncertainties as to how climate change concerns will ultimately impact us and various factors that may be out of our control. These uncertainties include transition risks related to laws and regulations, technology and business operations, or economic and market conditions. Research and development of technologies, innovations, and advancements may not evolve as anticipated in order to provide cost-effective alternatives to traditional energy sources. We could suffer financial loss, reputational damage, litigation, or other negative repercussions if we are unable to meet our voluntary GHG reduction goals. In addition, there are physical risks associated with adapting to changing climate conditions and extreme weather events. Further, assessment of the science to evaluate and limit global temperature rise continues to evolve. We could incur costs or other obligations to comply with future GHG regulations, and could become the target of legal claims or challenges, because generating electricity using fossil fuels emits GHGs. Further, investors may determine that we are too reliant on fossil fuels, reducing demand for our stock, which may cause our stock price to decrease, or investors may not buy our debt securities, which may cause our cost of capital to increase. We could face additional pressures from customers, investors or other stakeholders to more rapidly reduce GHG emissions on a voluntary-basis, including faster adoption of lower GHG emitting technologies and management of excess renewable energy credits. The pace and feasibility to fully achieve decarbonization is also contingent on the future development and full-scale deployment of emerging energy technologies and supporting infrastructure, as well as electrification of other economic sectors. Changing economic conditions and drivers to support significant load growth, including data centers, could influence electric demand. This could affect the timing of retirement for our existing coal-fired EGUs, and our need to add new fossil-fueled generation resources due to growing electric loads. We may not be able to meet our resource adequacy requirements if GHG regulations require us to shut down fossil fuel generating facilities before we can build new generating facilities to meet growing demand for electricity. We may not be able to recover all costs for projects to reduce GHG emissions in rates if regulators determine that the pace of GHG emissions efforts or new technologies are not prudent. The extent of the U.S. Environmental Protection Agency’s proposed rules to regulate GHG emissions at fossil-fuel fired EGUs and specific impacts, including state plans to implement the emissions reductions, remains uncertain. There could also be changes by the current or future Presidential or Gubernatorial Administrations. Various legislative and regulatory proposals to address climate change at the national, state and local levels continue to be introduced. Potential future requirements to reduce GHGs from the energy and manufacturing sectors could affect our operations in various ways. Regulation or legislation mandating GHG emissions reductions or other clean energy standards affecting utility companies could materially increase costs, causing some EGUs to be uneconomical to operate or maintain. We are vulnerable to potential risks associated with the construction of EGUs that may extend to our supply chain and natural gas operations. Regulation of oil and gas production could affect our upstream supply of natural gas for electricity generation and to provide directly to our residential and business customers from our local distribution company. This could result in rapid increased demand for alternative non-fossil fuel energy sources and economy-wide electrification. Changes to regional and local climate trends such as the frequency, seasonality, and severity of weather conditions could directly and indirectly impact our company. Acute and chronic physical risks could disrupt our operations or affect our property. Furthermore, it could affect the timing of peak demand and overall energy consumption of our customers. We cannot provide any assurance regarding the potential impacts of climate change or related policies and regulations to reduce GHG emissions on our operations, which could have a material adverse impact on our financial condition and results of operations. 18 Table of Contents Changes to certain tax elections, tax regulations and future taxable income could negatively impact our financial condition and results of operations - We have significantly reduced our federal and state income tax obligations through tax planning strategies and the utilization of bonus depreciation deductions for certain expenditures for property. These tax planning strategies and bonus depreciation deductions have reduced taxable income, which in turn has generated large tax credit carryforwards. We plan to utilize all of these tax credit carryforwards in the future to reduce our income tax obligations. If we cannot generate enough taxable income in the future to utilize all of the tax credit carryforwards before they expire due to lower than expected financial performance or changes to tax regulations, we may incur material charges to earnings. The Inflation Reduction Act of 2022 allows for the sale or transfer of eligible renewable tax credits to other taxpayers. We have sold, and continue to plan to sell, a substantial amount of our eligible renewable tax credits. However, the One Big Beautiful Bill Act (OBBB Act) includes significant changes to renewable tax credits, including accelerating the termination of production tax credits and investment tax credits. These changes may materially limit our ability to sell or transfer renewable tax credits at reasonable terms in future periods. The inability to sell renewable tax credits at reasonable terms, or the determination that renewable tax credits that we generate or sell are not eligible or are eligible at a different rate, could materially impact our tax credit carryforward position or result in liability to purchasers of the tax credits, which could subject us to significant litigation, liability and costs. Repeal or amendment of the Inflation Reduction Act of 2022, or portions of the Inflation Reduction Act of 2022, could have an adverse impact on our financial condition and results of operations, including, but not limited to, a material increase in customer costs, a material decrease in cash flows from operating activities, which could impact metrics used by rating agencies, and a negative impact on the economics of future planned renewable and energy storage projects. In addition, our tax liability is determined by our taxable income multiplied by the current tax rates in effect. If the federal or state tax rates are increased, state income tax apportionment is increased, or we become subject to a corporate alternative minimum tax, we may experience adverse impacts to our financial condition and results of operations until those rates are reflected in our regulatory filings. Our utility business currently operates wind and solar generating facilities, which generate production tax credits that are eligible to be used to reduce our federal tax obligations. The amount of production tax credits we earn is dependent on the level of electricity output generated by our qualifying generating facilities and sold to an unrelated buyer, and the applicable tax credit rate. A variety of operating and economic parameters, including transmission constraints, the imbalance of supply and demand of energy resulting in unfavorable pricing for wind or solar energy, adverse weather conditions and breakdown or failure of equipment, could significantly reduce the production tax credits generated by our wind or solar facilities resulting in a material adverse impact on our financial condition and results of operations. The OBBB Act’s early termination of production tax credits for projects beginning construction more than 12 months after enactment may also limit our ability to qualify new facilities for future production tax credits. Our utility business is developing energy storage facilities, which are expected to generate investment tax credits. Investment tax credits are dependent on the tax capitalized costs of the qualifying generating facilities and the applicable tax credit rate. If there is a disagreement on the qualifying costs or whether the facility qualifies for higher levels of investment tax credits, the amount of investment tax credits awarded may be significantly reduced, possibly adversely impacting our financial condition and results of operations. If energy storage facilities are not completed in the anticipated timeframe or investment tax credits are not able to be generated or sold due to the repeal or amendment of the Inflation Reduction Act of 2022, or new limitations imposed by the OBBB Act, we may experience adverse impacts on our financial condition and results of operations. The Inflation Reduction Act of 2022 introduced new labor requirements that are required to qualify for the full value of renewable tax credits. Failure to meet these requirements on renewable projects that began construction after January 28, 2023 could result in a significant reduction in the amount of renewable tax credits, which could adversely impact our financial condition and results of operations. The Inflation Reduction Act and related guidance also include limitations on the use of components and/or financing from entities with ties to certain foreign countries. If our generation or energy storage projects include equipment or subcomponents sourced from entities with ties to certain foreign countries, related production or investment tax credits may be reduced or denied, which could increase customer costs and adversely affect our financial condition. The OBBB Act further expands limitations on the use of components and/or financing from entities with ties to certain foreign countries, which could reduce or disqualify renewable tax credits for generation and energy storage projects. Risks Related to Business Operations Demand for energy may decrease - Our results of operations are affected by the demand for energy in our service territories. Energy demand may decrease due to many things, including economic conditions, proliferation of customer and third party-owned generation, technological advances that reduce the costs of renewable energy and energy storage solutions for our customers, government policies, such as the Inflation Reduction Act of 2022, which incentivize customer and third party-owned generation, loss of service territory or franchises, energy efficiency measures, changes in customer usage due to rate design changes, such as time of use rates, technological advances that improve energy efficiency, third-party disrupters, loss of wholesale customers, loss of customers that pursue their own renewable projects to achieve specific sustainability goals, and the adverse impact of tariffs on our customers. We may not realize anticipated or expected growth from large load growth customers, due to many factors, including changes in customers’ goals, changes in environmental policies, improvements in energy efficiency or technology, or competition from other companies. The loss of sales due to lower demand for energy may increase our rates for remaining customers, as our rates must cover our fixed costs. Increased customer rates may cause decreased demand for energy as customers move to customer and third party-owned generation and implement energy efficiency measures to reduce costs. The loss of customers, the inability to replace those customers with new customers, and the decrease in demand for energy could negatively impact our financial condition and results of operations. 19 Table of Contents Our utility business is seasonal and may be adversely affected by the impacts of weather - Electric and gas utility businesses are seasonal businesses. Demand for electricity is greater in the summer months associated with higher air conditioning needs and winter months associated with higher heating needs. Demand for natural gas depends significantly upon temperature patterns in winter months due to heavy use in residential and commercial heating. As a result, our overall operating results in the future may fluctuate substantially on a seasonal basis. In addition, we have historically generated less revenues and income when temperatures are warmer in the winter and/or cooler in the summer. Thus, mild winters and/or summers could have an adverse impact on our financial condition and results of operations. A cyber attack may disrupt our operations or lead to a loss or misuse of confidential and proprietary information or potential liability - We operate in an industry that requires the continuous use and operation of information and telecommunications systems. We face threats from use of malicious code (such as malware, viruses and ransomware), employee theft or misuse, vulnerabilities (such as the log4j and MOVEit vulnerabilities), fraud attempts, phishing attacks and advanced persistent threats. This includes threats from nation-state actors (such as VOLT TYPHOON and SALT TYPHOON), which have demonstrated an increased focus on targeting critical industries, including telecommunications and energy. Incidents of ransomware attacks have been increasing in frequency and magnitude. Emerging artificial intelligence technologies may be used to develop new hacking tools, exploit vulnerabilities, obscure malicious activities, and increase the difficulty detecting threats. Cyber attacks targeting electronic control systems used at our generating facilities and for electric and gas distribution systems could result in a full or partial disruption of our electric and/or gas operations. We have relied on a global supply chain for certain components of our operating and technology systems, which may increase our exposure to cyber attacks. Any disruption of these operations could result in a loss of service to customers and a significant decrease in revenues, as well as significant expense to repair system damage and remedy security breaches. Due to the evolving nature of cyber attacks and cybersecurity, our current safeguards to protect our operating systems and information technology assets may not always be effective. We rely on third parties for software to protect against cyber attacks and we are at risk if such third parties are targets of cyber attacks. Measures taken to avoid, detect, mitigate or recover from cybersecurity breaches or incidents may be insufficient or become ineffective, and there are no assurances that cybersecurity breaches or incidents will not impact our business, operations and financial condition. If the technology systems were to fail or be breached by a cyber attack or a computer virus, and not be recovered in a timely fashion, we may be unable to fulfill critical business functions and confidential data could be compromised, adversely impacting our financial condition and results of operation. In addition, we use information technology systems to collect and retain sensitive information, including personal information about our customers, shareowners and employees, which is subject to privacy laws and regulations. In some cases, we outsource administration of certain functions to vendors that have been or could be targets of cyber attacks. Any theft, loss and/or fraudulent use of customer, shareowner, employee or proprietary data as a result of a cyber attack could subject us to significant litigation, liability and costs, as well as adversely impact our reputation with customers and regulators, among others. Our strategy includes large construction projects, which are subject to risks - Our strategy includes constructing renewable generating facilities, energy storage facilities, natural gas-fired generating facilities, and large-scale additions and upgrades to our electric and gas distribution systems and generating assets. These construction and upgrade projects are subject to various risks. These risks include: the inability to obtain necessary regulatory approvals and permits in a timely manner; adverse interpretation or enforcement of permit conditions; changes in applicable laws or regulations; changes in costs of materials, equipment, commodities, fuel or labor including due to inflation, tariffs or labor issues; delays caused by construction accidents or injuries; shortages in materials, equipment, or qualified labor; changes to the scope or timing of the projects; general contractors, subcontractors, or equipment not performing as required under their contracts; the inability to agree to contract terms or disputes in contract terms; the inability to successfully resolve warranty claims; poor initial cost estimates; work stoppages; adverse weather conditions; government actions; legal action; unforeseen engineering or technology issues; limited access to capital or other financing arrangements; and other adverse economic conditions. We outsource certain business functions to third-party suppliers and service providers, and substandard performance by those third parties could harm our business, reputation and results of operations. We may not be able to recover all costs for the projects in rates and face increased risk of potential impairment of our project investment if a construction project is not completed or is delayed, or final costs exceed expectations or the costs approved by our regulators. We may not be able to meet capacity requirements, including new demand from high usage customers, to comply with electric demand planning reserve margins if a construction project is not completed or is delayed. Inability to recover costs, or inability to complete projects or recover costs in a timely manner, could adversely impact our financial condition and results of operations. Supply chain disruptions could negatively impact our operations and implementation of our strategy - Our operations and strategy depend on the global supply chain to procure the equipment, materials and other resources necessary to provide services in a safe and reliable manner and construct new utility infrastructure. The global supply chain has experienced, and is expected to continue to experience, disruptions due to a multitude of factors, such as geopolitical issues, supplier manufacturing constraints, labor issues, transportation issues, tariffs, changes in laws, executive orders, resource availability, long lead times, tighter credit markets, inflation, pandemics and weather. These disruptions have impacted, and are expected to continue to impact, our ability to receive critical materials, supplies and services in a timely and economic manner. This could have an adverse impact by increasing costs and delaying the construction, maintenance or repair of items that are needed to support normal operations or are necessary to our construction projects to implement our strategy. Inability to recover higher costs, or inability to complete projects in a timely manner, could adversely impact our financial condition and results of operations. 20 Table of Contents We face risks associated with operating electric and natural gas infrastructure - The operation of electric generation and distribution infrastructure involves many risks, including start-up risks, breakdown or failure of equipment, fires developing from our power lines, transformers, energy storage facilities, or substations, dam failure at one of our hydroelectric facilities, the dependence on a specific fuel source, including the supply and transportation of fuel, the risk of performance below expected or contracted levels of output or efficiency, members of the public or contractors coming into contact with our infrastructure, public and employee safety, operator error, and ruptured oil and chemical tanks. The operation of our natural gas distribution and transportation infrastructure also involves many risks, such as leaks, explosions, mechanical problems, members of the public or contractors coming into contact with our infrastructure, and employee and public safety. In addition, the North American electric transmission grid is highly interconnected and, in extraordinary circumstances, disruptions at particular points within the grid could cause an extensive power outage in our service territories. Increased utilization of customer- and third party-owned generation technologies could also disrupt the reliability and balance of the electricity grid. Further, the electric transmission system in our utilities’ service territories can experience constraints, limiting our ability to transmit electricity. The transmission constraints could result in an inability to deliver electricity from generating facilities, particularly wind and solar generating facilities, to the national grid, or to access lower cost sources of electricity. We may not be able to provide sufficient transmission capacity in a timely manner or transmission providers may be unable to timely provide transmission upgrades to enable connecting new generation to the grid, which could delay expected system load demand from large load growth customers such as data centers, expose us to market purchases and reduce expected revenues. These risks could cause significant harm to employees, customers and the public, including loss of human life, significant damage to property, adverse impacts on the environment and impairment of our operations, all of which could result in substantial financial losses to us. We are also responsible for compliance with new and changing regulatory standards involving safety, reliability and environmental compliance, including regulations under the Pipeline and Hazardous Materials Safety Administration, the Occupational Health and Safety Administration, the North American Electric Reliability Corporation and the Department of Homeland Security Transportation Security Administration. Failure to meet these regulatory standards could result in substantial fines. Lastly, we have obligations to provide electric and natural gas service to customers under regulatory requirements and contractual commitments. Failure to meet our service obligations could adversely impact our financial condition and results of operations. Storms or other natural disasters may impact our operations in unpredictable ways - Storms and other natural disasters, including events such as floods, tornadoes, windstorms like the 2020 derecho in Iowa, blizzards, ice storms, extreme hot temperatures, extreme cold temperatures, fires, wildfires, solar flares or pandemics may adversely impact our ability to generate, purchase or distribute electric energy and gas or obtain fuel or other critical supplies. In addition, we could incur large costs to repair damage to our generating facilities and electric and gas infrastructure, or costs related to environmental remediation, due to storms or other natural disasters. The restoration costs may not be fully covered by insurance policies and may not be fully recovered in rates, or recovery in rates may be delayed. Insurance coverage may not continue to be available at all, or at rates or terms similar to those presently available to us. In addition, our insurance may not be sufficient or effective under all circumstances and against all hazards or liabilities to which we may be subject. Any losses for which we are not fully insured or that are not covered by insurance at all could materially adversely affect our results of operations and financial position. Storms and natural disasters may impact our customers and the resulting reduced demand for energy could cause lower sales and revenues, which may not be replaced or recovered in rates, or rate recovery may be delayed. Any of these items could adversely impact our financial condition and results of operations. Threats of terrorism and catastrophic events that could result from terrorism may impact our operations in unpredictable ways - We are subject to direct and indirect effects of terrorist threats and activities. Generation, transmission and distribution facilities, in general, have been identified as potential targets of physical or cyber attacks. Physical attacks on transmission and distribution facilities that appeared to be terrorist-style attacks have occurred. Our gas distribution system could also be the target of terrorist threats and activities. The risks posed by such attacks could include, among other things, the inability to generate, purchase or distribute electric energy or obtain fuel sources, the increased cost of security and insurance, the disruption of, volatility in, or other effects on capital markets, and a decline in the economy and/or energy usage within our service territories, all of which could adversely impact our financial condition and results of operations. In addition, the cost of repairing damage to our facilities and infrastructure caused by acts of terrorism, and the loss of revenue if such events prevent us from providing utility service to our customers, could adversely impact our financial condition and results of operations. 21 Table of Contents We may not be able to fully recover costs related to commodity prices - We have natural gas and coal supply and transportation contracts in place for some of the natural gas and coal we require to generate electricity. We also have transportation and supply agreements in place to facilitate delivery of natural gas to our customers. Our counterparties to these contracts may not fulfill their obligations to provide natural gas, coal, financial settlements or collateral to us due to financial or operational problems caused by natural disasters, severe weather, economic conditions, labor shortages, employee strikes, transportation issues, pandemics, physical attacks or cyber attacks. If we were unable to obtain enough natural gas or coal for our EGUs under our existing contracts, or to obtain electricity under existing or future purchased power agreements, we could be required to purchase natural gas or coal at higher prices, need to secure higher cost delivery of natural gas or coal, be forced to curtail the operation of our natural gas-fired or coal-fired generating facilities, be forced to purchase electricity from higher-cost generating resources in the MISO energy market and/or be required to purchase replacement capacity to comply with electric demand planning reserve margins. We may be obligated to pay for coal deliveries under our contracts even if our coal-fired generating facilities do not operate enough to fully utilize the amounts of coal covered by the contracts. If, for natural gas delivery to our customers, we were unable to obtain our natural gas supply requirements under existing or future natural gas supply and transportation contracts, we could be required to purchase natural gas at higher prices from other sources. Natural gas market prices have been volatile in the past and could be volatile in the future due to additional future regulations, increased demand including due to new natural gas-fired generating facilities, increased liquified natural gas demand from foreign countries, limited global suppliers of natural gas, periods of extremely cold temperatures or disruption in supply caused by major storms or pipeline explosions. Our utility business also operates wind and solar generating facilities that sell electricity in the MISO energy market. If MISO energy market prices result in unfavorable pricing for wind or solar energy, this may reduce the energy market revenue produced by those facilities and result in higher electricity costs that would need to be recovered from customers. We may not be able to pass on all of the changes in costs to our customers, especially at WPL where we do not have an automatic retail electric fuel cost adjustment clause to timely recover such costs and where electric fuel cost recovery may be limited if WPL earns in excess of its authorized return on common equity. Increases in prices and costs due to disruptions that are not recovered in rates fully or not recovered in a timely manner, may adversely impact our financial condition and results of operations. Energy industry changes could have a negative effect on our businesses - We operate in a highly regulated business environment. The advent of new and unregulated markets has the potential to significantly impact our financial condition and results of operations. Further, competitors may not be subject to the same operating, regulatory and financial requirements that we are, potentially causing a substantial competitive disadvantage for us. Changes in public policy, such as new tax incentives that we cannot take advantage of or efforts to deregulate the utility industry, could provide an advantage to competitors. Changes in technology could also alter the channels through which electric customers produce, store, buy or utilize power, which could reduce the revenues or increase the expenses of our utility companies. Increased competition in our primary retail electric service territories may have an adverse impact on our financial condition and results of operations. We face risks related to non-utility operations - We rely on our non-utility operations for a portion of our earnings. If our non-utility holdings do not perform at expected levels, we could experience an adverse impact on our financial condition and results of operations. Risks Related to Economic, Financial and Labor Market Conditions We are subject to employee workforce factors that could affect our businesses - We operate in an industry that requires specialized technical skills. Further, we must build a workforce that is innovative, customer-focused and competitive to thrive in the future in order to successfully implement our strategy. We have seen and anticipate a steady pace of retirements due to our aging workforce. The labor market for our employees is very competitive, increasing the likelihood that we may lose critical employees or have difficulty hiring qualified employees for critical roles and not have enough time to adequately train employees to prepare for upcoming retirements. It may be difficult to hire and retain such a skilled workforce due to labor market conditions, such as low unemployment rates in our service territories, the length of time employees need to acquire the skills, and general competition for talent. The competitive employment market also increases the amounts we pay our employees in critical positions, which we may be unable to recover in rates. We are also subject to collective bargaining agreements covering approximately 1,700 employees. Any work stoppage experienced in connection with negotiations of collective bargaining agreements could adversely affect our financial condition and results of operations as well as our ability to implement our strategy. We are subject to limitations on our ability to pay dividends - Alliant Energy is a holding company with no significant operations of its own. The primary sources of funds for Alliant Energy to pay dividends to its shareowners are dividends and distributions from its subsidiaries, primarily its utility subsidiaries. Our subsidiaries are separate and distinct legal entities and have no obligation to pay any amounts to Alliant Energy, whether by dividends, distributions, loans or other payments. The ability of our subsidiaries to pay dividends or make distributions to Alliant Energy and, accordingly, our ability to pay dividends on Alliant Energy common stock will depend on regulatory limitations, earnings, cash flows, capital requirements and general financial condition of our subsidiaries. Our utilities have dividend payment restrictions based on the terms of regulatory limitations applicable to them. If we do not receive adequate dividends and distributions from our subsidiaries, then we may not be able to make, or may have to reduce, dividend payments on Alliant Energy common stock. 22 Table of Contents We are subject to risks related to inflation - We have experienced a significant increase in inflation. The impact of supply chain disruptions and other factors continue to create uncertainty in near-term economic conditions, including whether inflation will continue and at what rate. Increases in inflation raise our costs for labor, materials and services. Inflation may also cause interest rates to increase or stay elevated, increasing our cost of capital. Failure to timely recover these increased costs in rates may adversely impact our financial condition and results of operations. Further, increased costs due to inflation will directly and indirectly increase customer costs, which may decrease demand for energy or impact our customers’ ability to pay their bills, which could adversely impact our financial condition and results of operations. We may incur material post-closing adjustments related to past asset and business divestitures - We have sold certain non-utility subsidiaries and may continue to incur liabilities relating to our previous ownership of, or the transactions pursuant to which we disposed of, these subsidiaries and assets. Any potential liability depends on a number of factors outside of our control. Any required payments on retained liabilities, guarantees or indemnification obligations with respect to past and future asset or business divestitures could adversely impact our financial condition and results of operations. We are dependent on the capital markets and could be negatively impacted by disruptions in the capital markets - Successful implementation of our strategy is dependent upon our ability to access the capital markets. We have forecasted capital expenditures of approximately $13 billion over the next four years. Disruption, uncertainty or volatility in the capital markets could increase our cost of capital or limit our ability to raise funds needed to operate our businesses. Disruptions could be caused by Federal Reserve policies and actions, currency concerns, inflation, economic downturn or uncertainty, monetary policies, a negative view of the utility industry or our company, failures of financial institutions, U.S. debt management concerns, U.S. debt limit and budget debates, including government shutdowns, European and worldwide sovereign debt concerns, other global or geopolitical events, or other factors. IPL and WPL have entered into conditional commitments with the U.S. Department of Energy Office of Energy Dominance Financing, formerly the Loan Programs Office, for loan guarantees of approximately $3 billion in aggregate and WPL has been selected for additional grants. The inability to access these funds due to federal action or other reasons may increase our costs and interest rates. Increases in interest rates will cause the cost of capital to increase and may cause the price of our equity securities to decline. Any disruptions in capital markets could adversely impact our ability to implement our strategy. We rely on our strong credit ratings to access the credit markets. If our credit ratings are downgraded for any reason, such as worsening credit metric impacts, reduced liquidity, negative changes to our regulatory environment, or general negative outlook for the utility industry, we could pay higher interest rates in future financings, the pool of potential lenders could be reduced, borrowing costs under existing credit facilities could increase, our access to the commercial paper market could be limited, or we could be required to provide additional credit assurance, including cash collateral, to contract counterparties. If our access to capital were to become significantly constrained or costs of capital increased significantly due to lowered credit ratings, prevailing industry conditions, regulatory constraints, volatility of the capital markets, inflation or other factors, our financial condition and results of operations could be adversely affected. Our pension and other postretirement benefits plans are subject to investment and interest rate risk that could negatively impact our financial condition - We have pension and other postretirement benefits plans that provide benefits to many of our employees and retirees. Costs of providing benefits and related funding requirements of these plans are subject to changes in the liabilities of the plans and market value of the assets that fund the plans. The funded status of the plans and the related costs reflected in our financial statements are affected by various factors, which are subject to an inherent degree of uncertainty, including economic conditions, financial market performance, interest rates, life expectancies and demographics. Recessions and volatility in the domestic and international financial markets have negatively affected the asset values of our pension plans at various times in the past. Poor investment returns or lower interest rates may necessitate accelerated funding of the plans to meet minimum federal government requirements, which could have an adverse impact on our financial condition and results of operations. ITEM 1B. UNRESOLVED STAFF COMMENTS None. ITEM 1C. CYBERSECURITY We operate in an industry that requires the continuous use and operation of information and telecommunications systems. In addition, we use information technology systems to collect and retain sensitive information, including confidential and proprietary information about our businesses, and personal information about our customers, shareowners and employees. Cybersecurity risks are identified as key risks through the enterprise risk management (ERM) program. These risks could include use of malicious code, employee theft or misuse, advanced persistent threats, vulnerabilities, fraud attempts, and phishing attacks that could cause, among others, an operations or information technology system failure, or breach or loss of sensitive information. The potential impact of cybersecurity risks on our business operations, results of operations or financial condition is discussed in the “ R i sks R elated to Business Operations ” section of Item 1A “ Risk Factors .” We have not had any material cybersecurity breaches or incidents and have not incurred any material expenses, penalties or settlement costs related to any cybersecurity breaches or incidents. However, measures that we take to avoid, detect, mitigate or recover from cybersecurity breaches or incidents may be insufficient or become ineffective, and there are no assurances that cybersecurity breaches or incidents will not impact our business operations and strategy, results of operations and financial condition. 23 Table of Contents We maintain a cybersecurity program that includes development and implementation of policies, procedures and tools designed to help ensure availability of critical operations, information technology and telecommunication systems and safeguard sensitive informa tion. The cybersecurity program is assessed against industry standards, including the National Institute of Standards and Technology Cybersecurity Fram ework. This assessment is conducted by a third party periodically and internally at least annually. We are also required to comply with cybersecurity standards under the North American Electric Reliability Corporation (NERC) Critical Infrastructure Protection and by the Department of Homeland Security Transportation Security Administration. We also periodically collaborate with federal and state law enforcement experts, external assessors, consultants, industry peers and other third parties in connection with understanding market and threat conditions used to identify, assess and mitigate cyber security risks. The cybersecurity program includes: • a dedicated cybersecurity team; • operations, information technology and telecommunication systems implemented with segmentation and multiple levels of access controls; • a security operations center that continuously monitors information technology and telecommunications systems; • an incident response team composed of individuals from the information technology, operations, accounting, finance, legal, and communications departments, as needed, which is activated to respond to cybersecurity incidents; • periodic drills and exercises to address risks and prepare for extraordinary scenarios, including industry collaboration on incident preparation, such as GridEx drills hosted by NERC, participation in a full activation drill at least annually, and several tabletop drills during the year; • periodic drills with the full executive team, including the Chief Executive Officer (CEO), Chief Financial Officer (CFO), Chief Accounting Officer (CAO), Chief Information Officer (CIO) and General Counsel; • periodic information security awareness training and phishing simulations for employees and contractors who access our networks; • periodic security assessments of evolving risks and threats that lead to strengthening of cybersecurity measures; • implementation of automation solutions to strengthen detection and response capabilities; and • maintenance of cyber liability insurance. We also address cybersecurity risks associated with third-party service providers, including those in our supply chain or who have access to our customer and employee data or our information technology systems. Third-party risks are included in the ERM program and the cybersecurity program. Diligence is performed on third parties that have access to information technology systems, data or facilities that house such systems or data. High-risk vendors are identified and continually monitored for cybersecurity threat risks. Additionally, third parties that have access to information technology systems, data or facilities that house such systems or data, agree by contract to manage their cybersecurity risks, provide notification in the event of a cybersecurity incident, and be subject to cybersecurity audits. Our cybersecurity program is overseen by our Senior Vice President and CIO , who has nearly four decades of experience in information technology, including two decades as a CIO, having previously held CIO roles with other organizations, as well as experience in the utility sector. The CIO oversees a team dedicated to the support of cybersecurity tools and the overall cybersecurity program. The CIO reports to the Executive Vice President and Chief Strategy Officer. The CIO provides periodic briefs regarding prevention, detection, mitigation and remediation of cybersecurity incidents, as well as risks, threats and the threat landscape to the Board and executive management, including the CEO, CFO and CAO. These briefs are used to help continuously improve our cybersecurity program and to inform risk assessments as part of the ERM program. The full Board of Directors is responsible for oversight of our key cybersecurity risks. The Board retains direct oversight of cybersecurity matters to best utilize the experiences and expertise of all Board members. Management, including the CIO, provides reports approximately quarterly to the Board regarding risks, threats, the threat landscape, assessments of and improvements to the cybersecurity program, and internal response preparedness. The Audit Committee provides oversight of policies on risk assessment, controls, and accounting risk exposure, reviews cybersecurity disclosures in filings with the Securities and Exchange Commission, and reviews internal audit reports related to cybersecurity processes. The Operations Committee provides focused oversight of operational and capital‑related cybersecurity and technology matters. 24 Table of Contents ITEM 2. PROPERTIES Alliant Energy - As a holding company, Alliant Energy doesn’t directly own any significant properties other than the stock of its subsidiaries. The principal properties of those subsidiaries are as follows: IPL and WPL Electric - At December 31, 2025, IPL’s and WPL’s facilities by primary fuel type were as follows: IPL Generating In-service Capacity Name of Facility and Location Dates in MW (a) Marshalltown Generating Station (Units 1-3); Marshalltown, IA 2017 666 Emery Generating Station (Units 1-3); Mason City, IA 2004 531 Marshalltown Combustion Turbines (Units 1-3); Marshalltown, IA 1978 155 Burlington Generating Station (Unit 1); Burlington, IA 1968 143 Prairie Creek Generating Station (Unit 4); Cedar Rapids, IA 1967 126 Burlington Combustion Turbines (Units 1-4); Burlington, IA 1994-1996 34 Total Gas 1,655 Upland Prairie (121 Units); Clay and Dickinson Cos., IA 2019 299 Whispering Willow - North (81 Units); Franklin Co., IA 2020 201 Whispering Willow - East (121 Units); Franklin Co., IA 2009 200 Golden Plains (82 Units); Winnebago and Kossuth Cos., IA 2020 200 English Farms (69 Units); Poweshiek Co., IA 2019 172 Richland (53 Units); Sac Co., IA 2020 131 Franklin County (60 Units); Franklin Co., IA 2012 99 Total Wind 1,302 Pleasant Creek (Units 1-2), Linn Co., IA 2024 200 Wever; Lee Co., IA 2024 150 Creston; Union Co., IA 2024 50 Dubuque; Dubuque, IA 2017 5 Marshalltown; Marshalltown, IA 2020 3 Customer-hosted and Community Solar; various locations in IA 2024-2025 18 Total Solar 426 Ottumwa Generating Station (Unit 1); Ottumwa, IA (b) 1981 336 George Neal Generating Station (Unit 4); Sioux City, IA (c) 1979 165 George Neal Generating Station (Unit 3); Sioux City, IA (d) 1975 143 Prairie Creek Generating Station (Units 1 and 3); Cedar Rapids, IA (e) 1958-1997 37 Louisa Generating Station (Unit 1); Louisa, IA (f) 1983 30 Total Coal 711 Lime Creek Combustion Turbines (Units 1-2); Mason City, IA 1991 72 Total Oil 72 Wever; Lee Co., IA 2025 99 Energy Storage; various locations in IA 2019-2023 9 Total Energy Storage 108 Total capacity 4,274 25 Table of Contents WPL Generating In-service Capacity Name of Facility and Location Dates in MW (a) Riverside Energy Center (Units 1-3); Beloit, WI 2004 530 West Riverside Energy Center (Units 1-3); Beloit, WI (g) 2020 390 Neenah Energy Facility (Units 1-2); Neenah, WI 2000 296 South Fond du Lac Combustion Turbines (2 Units); Fond du Lac, WI (h) 1994 164 Total Gas 1,380 Bent Tree (122 Units); Freeborn Co., MN 2010-2011 201 Kossuth (56 Units); Kossuth Co., IA 2020 152 Cedar Ridge (41 Units); Fond du Lac Co., WI 2008 68 Forward Wind Energy Center (37 Units); Dodge and Fond du Lac Cos., WI (i) 2008 59 Total Wind 480 Grant County, Grant Co., WI 2024 200 Wood County, Wood Co., WI 2022 150 Onion River, Sheboygan Co., WI 2023 150 Springfield, Dodge Co., WI 2023 100 Wautoma, Waushara Co., WI 2023 99 Crawfish River, Jefferson Co., WI 2023 75 Paddock, Rock Co., WI 2023 65 Bear Creek, Richland Co., WI 2022 50 North Rock, Rock Co., WI 2022 50 Albany, Green Co., WI 2023 50 Beaver Dam, Dodge Co., WI 2023 50 Cassville, Grant Co., WI 2023 50 West Riverside, Beloit, WI (f) 2021 2 Customer-hosted and Community Solar; various locations in WI 2021-2025 11 Total Solar 1,102 Columbia Energy Center (Units 1-2); Portage, WI (j) 1975-1978 596 Edgewater Generating Station (Unit 5); Sheboygan, WI 1985 405 Total Coal 1,001 Prairie du Sac (8 Units); Prairie du Sac, WI 1914-1940 13 Kilbourn (4 Units); Wisconsin Dells, WI 1926-1939 6 Total Hydro 19 Grant County, Grant Co., WI 2025 100 Wood County, Wood Co., WI 2025 75 Energy Storage; various locations in WI 2022-2023 9 Total Energy Storage 184 Total capacity 4,166 (a) Based on the summer installed generating capacity included in MISO’s resource adequacy process for the planning period from June 2025 through May 2026, except for wind facilities, solar facilities and energy storage, which are based on nameplate capacity. (b) Represents IPL’s 48% ownership interest, which is operated by IPL. (c) Represents IPL’s 25.695% ownership interest, which is operated by MidAmerican Energy Company. (d) Represents IPL’s 28% ownership interest, which is operated by MidAmerican Energy Company. (e) Subsequent to December 31, 2025, IPL retired Prairie Creek Unit 1 and fuel switched Prairie Creek Unit 3 to natural gas. (f) Represents IPL’s 4% ownership interest, which is operated by MidAmerican Energy Company. (g) Represents WPL’s 56.6% ownership interest, which is operated by WPL. (h) Represents Units 2 and 3, which WPL owns. WPL also operates, but does not own, South Fond du Lac Combustion Turbines Units 1 and 4. (i) Represents WPL’s 42.64% ownership interest, which is operated by Invenergy Services, LLC. (j) Represents WPL’s 53.5% ownership interest, which is operated by WPL. IPL and WPL own overhead electric distribution line, underground electric distribution cable and substation distribution transformers, substantially all of which are located in Iowa for IPL and Wisconsin for WPL. 26 Table of Contents Gas - IPL’s and WPL’s gas properties consist primarily of mains and services, meters, regulating and gate stations and other related transmission and distribution equipment. IPL’s and WPL’s gas distribution facilities include gas mains located in Iowa and Wisconsin, respectively. Other - Refer to Note 9 for information regarding WPL’s lease of the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business. Corporate Services - Corporate Services’ property included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2025 consisted primarily of computer software, and the corporate headquarters building located in Madison, Wisconsin. AEF - AEF’s principal properties included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2025 were as follows: Non-utility Generation - Includes the Sheboygan Falls Energy Facility, a 347 MW, simple-cycle, natural gas-fired facility near Sheboygan Falls, Wisconsin that was placed in service in 2005 and is leased to WPL. The summer installed generating capacity included in MISO’s resource adequacy process for the planning period from June 2025 through May 2026 for the Sheboygan Falls Energy Facility was 298 MW. Travero - Includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; and a rail-served warehouse in Iowa. Development-ready Sites - includes various rail-served and ready-to-build manufacturing and industrial sites throughout Iowa and Wisconsin, with access to various airports, interstate freeways and Alliant Energy’s electric services. ITEM 3. LEGAL PROCEEDINGS None. SEC regulations require Alliant Energy, IPL and WPL to disclose information about certain proceedings arising under federal, state or local environmental provisions when a governmental authority is a party to the proceedings and such proceedings involve potential monetary sanctions that Alliant Energy, IPL and WPL reasonably believe will exceed a specified threshold. Pursuant to the SEC regulations, Alliant Energy, IPL and WPL use a threshold of $1 million for purposes of determining whether disclosure of any such proceedings is required. Applying this threshold, there are no environmental matters to disclose for this period. Refer to Note 1 6 (c) for discussion of legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. ITEM 4. MINE SAFETY DISCLOSURES None. INFORMATION ABOUT EXECUTIVE OFFICERS The executive officers of Alliant Energy, IPL and WPL for which information must be included are the same; however, different positions may be held at the various registrants. None of the executive officers for Alliant Energy, IPL or WPL listed below are related to any member of the Board of Directors or nominee for director or any other executive officer. All of the executive officers have no definite terms of office and serve at the pleasure of the Board of Directors. The executive officers of Alliant Energy, IPL and WPL as of the date of this filing are as follows: Name Age as of Filing Date Positions Lisa M. Barton 60 Ms. Barton has served as President and Chief Executive Officer (CEO) and as a director since January 2024. She previously served as President and Chief Operating Officer (COO) since February 2023, as Executive Vice President (VP) and COO of American Electric Power Company, Inc. (AEP) from January 2021 to November 2022, and as Executive VP - Utilities of AEP from January 2020 to December 2020. Robert J. Durian 55 Mr. Durian has served as Executive VP and Chief Financial Officer (CFO) since February 2020. He previously served as Senior VP and CFO since February 2019. David A. de Leon 63 Mr. de Leon has served as Senior VP since January 2019. Mayuri N. Farlinger 43 Ms. Farlinger has served as VP since January 2022. She previously served as Director of Operations from January 2020 to December 2021. Raja Sundararajan 50 Mr. Sundararajan has served as Executive VP and Chief Strategy Officer since January 2026. He previously served as Executive VP since June 2023. He previously served as Executive VP - External Affairs of AEP since July 2022, as Senior VP - Regulatory and Customer Solutions of AEP from July 2021 to July 2022, and as President and COO of AEP Ohio from January 2019 to July 2021. 27 Table of Contents Name Age as of Filing Date Positions Antonio P. Smyth 50 Mr. Smyth has served as Executive VP of Power Generation and Gas Strategy since April 2025. He previously served as Executive VP - Grid Solutions of AEP since December 2024, Executive VP - Grid Solutions & Government Affairs of AEP from April 2023 to December 2024, Senior VP - Grid Solutions of AEP from January 2021 to April 2023, and Senior VP - Transmission Ventures, Strategy & Policy of AEP from October 2018 to December 2020. Rebecca C. Valcq 50 Ms. Valcq has served as VP since January 2026. She previously served as Assistant Vice President since 2024. From 2019 to 2024, she served as Chair of the Public Service Commission of Wisconsin. Dylan M. Syse 40 Mr. Syse has served as Chief Accounting Officer and Controller since March 2025. He previously served as Assistant Controller since November 2021, as Manager - Accounting and Reporting from May 2020 to November 2021, and as Manager - Accounting from May 2018 to April 2020. PART II ITEM 5. MARKET FOR REGISTRANTS’ COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Common Stock Data - Alliant Energy’s common stock trades on the Nasdaq Global Select Market under the symbol “LNT,” and the closing sales price at December 31, 2025 was $65.01. Shareowners - At December 31, 2025, there were 18,130 holders of record of Alliant Energy’s common stock, including holders through Alliant Energy’s Shareowner Direct Plan. Alliant Energy is the sole common shareowner of all 13,370,788 and 13,236,601 shares of IPL and WPL common stock, respectively, currently outstanding. As a result, there is no established public trading market for the common stock of either IPL or WPL. Dividends - In November 2025, Alliant Energy announced an increase in its targeted 2026 annual common stock dividend to $2.14 per share, which is equivalent to a quarterly rate of $0.535 per share, beginning with the February 2026 dividend payment. The timing and amount of future dividends is subject to approval of quarterly dividend declarations from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors. Common Stock Repurchases - A summary of Alliant Energy common stock repurchases for the quarter ended December 31, 2025 was as follows: Total Number Average Price Total Number of Shares Maximum Number (or Approximate of Shares Paid Per Purchased as Part of Dollar Value) of Shares That May Period Purchased (a) Share Publicly Announced Plan Yet Be Purchased Under the Plan (a) October 1 to October 31 5,449 $67.76 — N/A November 1 to November 30 2,723 68.10 — N/A December 1 to December 31 48 66.30 — N/A 8,220 67.86 — (a) All shares were purchased on the open market and held in a rabbi trust under the DCP. There is no limit on the number of shares of Alliant Energy common stock that may be held under the DCP, which currently does not have an expiration date. ITEM 6. [RESERVED] ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS This MDA includes information relating to Alliant Energy, IPL and WPL (collectively, the Utilities), as well as ATC Holdings, AEF and Corporate Services. Where appropriate, information relating to a specific entity has been segregated and labeled as such. The following discussion and analysis should be read in conjunction with the Financial Statements and Notes included in this report. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share. In addition, this MDA includes certain financial information for 2025 compared to 2024. Refer to MDA in the combined 2024 Form 10-K for details on certain financial information for 2024 compared to 2023. 28 Table of Contents OVERVIEW Mission, Purpose and Strategy Alliant Energy’s mission is to deliver the energy solutions and exceptional service that its customers and communities count on - affordably, safely, reliably and responsibly. This mission aligns with Alliant Energy’s purpose - to serve customers and build stronger communities - which guides it through the evolving dynamics of the economy and the energy industry. Alliant Energy leads as a corporate citizen, advancing environmental stewardship and supporting the communities in its service territories. Alliant Energy’s mission and purpose are supported by a strategy focused on meeting evolving customer expectations, delivering attractive returns for investors, and advancing emerging technologies and generation to enable safe, secure and future-ready energy production. This strategy includes the following key elements: Providing affordable energy solutions for customers - Alliant Energy’s strategy focuses on affordable energy solutions that support retention and growth of existing customers and attract new customers to its service territories. Key Highlights - • Alliant Energy’s resource plan is the roadmap for building a strong and resilient energy future to meet the growing energy needs across Iowa and Wisconsin. This long-term plan expands generation capacity and includes a balanced mix of natural gas, energy storage, new renewable generation, improvements at existing natural gas-fired EGUs and refurbishments at existing wind farms. It is designed to deliver the reliable, affordable energy customers count on by efficiently increasing the capabilities of existing generation through gas and wind facility upgrades while also building larger scale natural gas facilities to capture economies of scale. Alliant Energy’s industry-leading wind and solar energy resources provide zero-fuel cost generation as well as generate renewable tax credits that are provided to its electric customers. By enhancing new and existing energy sources while maximizing traditional energy sources, Alliant Energy is helping support economic growth, maintain reliability and keep customer bills affordable. At the same time, Alliant Energy is modernizing its distribution system to create a smarter, more adaptable infrastructure that increases resiliency and supports evolving energy technologies. By advancing a responsible approach to energy resources, Alliant Energy can deliver what matters most to the customers and communities it serves - affordably, safely and reliably. • Higher electric capacity revenues from existing generation resources beginning in 2025 are expected to provide cost benefits to WPL’s retail electric customers in the future through its fuel cost recovery mechanism. • Alliant Energy, IPL and WPL have utilized, and expect to continue to utilize, various provisions of the Inflation Reduction Act of 2022 to enhance tax benefits provided to customers that are expected from wind, solar and energy storage projects in Iowa and Wisconsin, including transferring certain future tax credits from such projects to other corporate taxpayers. Refer to Note 1(c) for discussion of $285 million, $216 million and $98 million of proceeds from renewable tax credits transferred to other corporate taxpayers in 2025, 2024 and 2023, respectively. • Reductions in Iowa corporate income tax rates resulting from tax reform enacted in 2022 are expected to provide cost benefits to IPL’s electric and gas customers in the future. IPL’s retail electric and gas customers began receiving these benefits with the new base rates effective October 1, 2024. • IPL provided billing credits to its retail electric customers through the tax benefit rider of $52 million and $16 million in 2025 and 2024, respectively. IPL also provided its retail electric customers $162 million and $40 million in credits on customers’ bills related to production tax credits through its fuel-related cost recovery mechanism in 2025 and 2024, respectively. • IPL maintaining flat base rates for its retail electric and gas customers from 2021 through September 30, 2024, as well as a retail electric base rate moratorium from October 2025 through September 2029 approved by the IUC in IPL’s most recent retail electric rate review. • Completion of a restructuring and voluntary employee separation program in 2024, which is expected to reduce operation and maintenance expenses in the future. Refer to Note 12 for discussion of this program. • IPL and WPL have entered into conditional commitments with the U.S. Department of Energy Office of Energy Dominance Financing, formerly the Loan Programs Office, for loan guarantees of approximately $1.4 billion and $1.6 billion, respectively. If finalized, such loans would provide low interest financing for IPL’s and WPL’s expected construction of eligible projects as defined in the governing agreement. • In July 2024, the U.S. Department of Energy Office of Electricity - formerly administered by the Office of Clean Energy Demonstrations awarded WPL’s Columbia Energy Storage Project, an approximately 20 MW compressed CO2-based long-duration energy storage system at the Columbia Energy Center site, up to approximately $30 million in grant funding during construction of the project. • In April 2025, WPL submitted an application to the U.S. Army Corps of Engineers for up to $45 million in loans through the Corps Water Infrastructure Financing Program. If finalized, such loans would provide low interest financing for various proposed safety projects at WPL’s Kilbourn and Prairie du Sac hydro EGUs. • IPL and WPL executed agreements to enable fiber connectivity to one of its data center customers by leasing underground conduit in their service territories, which is expected to provide cost benefits to IPL’s and WPL’s existing customers. Making customer-focused investments - Alliant Energy’s strategic priorities include making customer-focused investments to provide reliable, resilient, and sustainable energy solutions. Alliant Energy’s capital allocation strategy is focused on: • Growth: Developing energy resources to meet demand for future phases of economic development and transmission investments through ATC. 29 Table of Contents • Reliability and Resiliency: Investments to extend the flexibility, efficiency, capacity and optionality of existing resources including coal plant conversions and replacements, resiliency investments in natural gas storage, liquified natural gas and gas delivery, as well as reliability and safety investments in electric and gas distribution. • Customer Value: Improving customer and employee experiences through technology investments that increase operational efficiency, service effectiveness and organizational agility. Key Highlights (refer to “ Customer Investments ” for details) - • Over the next five years, Alliant Energy currently plans to develop and/or acquire new generation investments to add flexibility with evolving load growth, including approximately 1,600 MW of new natural gas resources, approximately 1,000 MW of new energy storage, approximately 1,300 MW of new renewable generation, improvements of approximately 410 MW at existing natural gas-fired EGUs, and refurbishments at approximately 450 MW of existing wind farms. Alliant Energy is currently evaluating the impact of potential additional demand from large load growth customers and MISO’s seasonal resource adequacy requirements on its resource plans and will update these generation investment plans as needed in the future. • Completion of new solar generation at WPL (1,089 MW in Wisconsin from 2022-2024) and IPL (400 MW in Iowa in 2024), and IPL’s refurbishment of the existing Franklin County wind farm in Iowa in 2024. • Completion of construction of energy storage projects totaling 175 MW at WPL and 99MW at IPL in 2025. • Completion of the Neenah Unit 1 and Sheboygan Falls Unit 1 advanced gas path projects in 2025, which increased the efficiency and capacity at each of these facilities. • Alliant Energy continues to partner with its commercial and industrial customers in Iowa and Wisconsin to help develop renewable solutions to support their sustainability initiatives. Growing customer demand - Alliant Energy’s strategy supports expanding electric and gas usage in its service territories by promoting electrification initiatives and economic development to grow at the pace of its customers. Key Highlights - • IPL has entered into electric service agreements with two new customers, and WPL has entered into an electric service agreement with one new customer, each of whom is constructing or expects to construct one or more data centers in IPL’s or WPL’s service territories. IPL’s and WPL’s currently executed electric service agreements include aggregate, peak demands of approximately 3 gigawatts. The energy resources to serve this expected load are included in the construction and acquisition table in “ Liquidity and Capital Resources .” The actual timing and amount of increases in IPL’s and WPL’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. • The IUC’s order for IPL’s most recent retail electric rate review includes the creation of an individual customer rate tariff, allowing IPL to attract new load growth to its service territory. In addition, Iowa’s Major Economic Growth Attraction program and Iowa’s and Wisconsin’s sales and use tax exemption for qualified data centers, encourage economic development in Alliant Energy’s service territory. • In May 2025 and October 2025, the IUC issued orders, with certain conditions, approving individual customer rates for data centers expected to be constructed in IPL’s service territory. In April 2025, WPL filed a request with the PSCW for approval of an individual customer rate for a data center expected to be constructed in its service territory. A decision from the PSCW is currently expected in the second quarter of 2026. • Various development-ready sites, which have transmission capabilities, are rail-served and in close proximity to a variety of transportation options, are located throughout Alliant Energy’s service territories. RESULTS OF OPERATIONS Financial Results Overview - The table below includes diluted EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance. Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners were as follows (dollars in millions, except per share amounts): 2025 2024 Income (Loss) EPS Income (Loss) EPS Utilities and Corporate Services $875 $3.39 $722 $2.81 ATC Holdings 41 0.16 40 0.16 Non-utility and Parent (106) (0.41) (72) (0.28) Alliant Energy Consolidated $810 $3.14 $690 $2.69 Alliant Energy’s Utilities and Corporate Services net income increased by $153 million in 2025 compared to 2024. The increase was primarily due to higher revenue requirements from capital investments, estimated temperature impacts on retail electric and gas sales, an asset valuation charge for IPL’s Lansing Generating Station as a result of the IUC order for IPL’s retail electric rate review in 2024, restructuring and voluntary separation charges in 2024, and an ARO charge allocated to the steam business at IPL due to the revised CCR Rule in 2024. These items were partially offset by higher other operation and maintenance expenses, depreciation and financing expenses. 30 Table of Contents Alliant Energy’s Non-utility and Parent net income decreased by $34 million in 2025 compared to 2024, primarily due to an asset valuation charge for Alliant Energy’s non-utility business in 2025, higher financing expense and a state income tax apportionment charge in 2025, partially offset by an adjustment of deferred tax assets due to Iowa tax reform in 2024. Net Income Variances - The following items contributed to increased (decreased) net income for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Revenues: Changes in electric utility (Refer to details below ) $325 $149 $176 Changes in gas utility (Refer to details below ) 60 15 45 Changes in other utility (3) (2) (1) Changes in non-utility (1) — — Changes in total revenues 381 162 220 Operating expenses: Changes in electric production fuel and purchased power (Refer to details below ) (114) (14) (100) Changes in electric transmission service (Refer to details below ) (12) (5) (7) Changes in cost of gas sold (Refer to details below ) (39) (7) (32) Asset valuation charge for IPL’s Lansing Generating Station in 2024 (Refer to Note 2 for details) 60 60 — Changes in other operation and maintenance (Refer to details below ) (64) (15) (27) Changes in depreciation and amortization (Higher primarily due to solar generation placed in service in 2024 and updated electric depreciation rates for IPL effective October 1, 2024) (74) (59) (13) Changes in taxes other than income taxes 1 1 1 Changes in total operating expenses (242) (39) (178) Changes in operating income 139 123 42 Other income and deductions: Changes in interest expense (Higher primarily due to financings completed in 2024 and 2025) (63) (34) (8) Changes in equity income from unconsolidated investments, net (Refer to Note 6 for details) (1) — — Changes in AFUDC 14 13 1 Changes in Other (4) (5) (4) Changes in total other income and deductions (54) (26) (11) Changes in income before income taxes 85 97 31 Changes in income taxes (Refer to Note 1 1 for details) 35 (2) 25 Changes in net income $120 $95 $56 31 Table of Contents Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), were as follows: Electric Gas Revenues MWhs Sold Revenues Dths Sold 2025 2024 2025 2024 2025 2024 2025 2024 Alliant Energy Retail $3,305 $3,009 25,122 24,569 $472 $419 49,363 43,489 Sales for resale: Wholesale 184 200 2,565 2,783 N/A N/A N/A N/A Bulk power and other 164 86 5,386 5,620 N/A N/A N/A N/A Transportation/Other 44 77 56 57 53 46 123,141 123,386 $3,697 $3,372 33,129 33,029 $525 $465 172,504 166,875 IPL Retail $1,801 $1,662 13,882 13,620 $234 $223 23,710 21,640 Sales for resale: Wholesale 39 61 481 750 N/A N/A N/A N/A Bulk power and other 28 (6) 1,777 1,138 N/A N/A N/A N/A Transportation/Other 28 30 31 32 31 27 44,489 43,075 $1,896 $1,747 16,171 15,540 $265 $250 68,199 64,715 WPL Retail $1,504 $1,347 11,240 10,949 $238 $196 25,653 21,849 Sales for resale: Wholesale 145 139 2,084 2,033 N/A N/A N/A N/A Bulk power and other 136 92 3,609 4,482 N/A N/A N/A N/A Transportation/Other 16 47 25 25 22 19 78,652 80,311 $1,801 $1,625 16,958 17,489 $260 $215 104,305 102,160 Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes increased 2% in 2025 compared to 2024, primarily due to changes in temperatures and higher sales to commercial and industrial customers. Alliant Energy’s retail gas sales volumes increased 14% in 2025 compared to 2024, primarily due to changes in temperatures. Estimated increases (decreases) to operating income from the impacts of temperatures were as follows (in millions): Electric Gas 2025 2024 Change 2025 2024 Change IPL $13 ($14) $27 ($4) ($12) $8 WPL 3 (15) 18 (1) (10) 9 Total Alliant Energy $16 ($29) $45 ($5) ($22) $17 Electric Sales for Resale - Bulk Power and Other - Bulk power and other volume changes were due to changes in sales in the wholesale energy markets operated by MISO. These changes are impacted by several factors, including the availability and dispatch of Alliant Energy’s EGUs and electricity demand within these wholesale energy markets. Changes in bulk power and other revenues were largely offset by changes in fuel-related costs, and therefore did not have a significant impact on operating income. Gas Transportation/Other - Gas transportation/other sales volume changes were largely due to changes in the gas volumes supplied to Alliant Energy’s natural gas-fired EGUs caused by the availability and dispatch of such EGUs. 32 Table of Contents Electric Utility Revenue Variances - The following items contributed to increased (decreased) electric utility revenues for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher revenue requirements (a)(b) $333 $271 $62 Higher sales for resale bulk power and other revenues (c) 78 34 44 Estimated changes in 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 1(g) ) 43 — 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) ) 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) — 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 (1) 13 (14) $325 $149 $176 (a) In September 2024, the IUC issued an order authorizing an annual base rate increase of $185 million for IPL’s retail electric customers, with customers receiving partially offsetting credits for the first 12 months through a tax benefit rider, for the October 2024 through September 2025 forward-looking Test Period. Rate changes were effective October 1, 2024, which reflect revenue requirement impacts of increasing electric rate base including investments in solar generation, updated depreciation rates, and certain incremental costs incurred resulting from the 2020 derecho windstorm. In addition, effective October 1, 2024, IPL’s renewable energy rider was discontinued, and certain production tax credits are credited to IPL’s retail electric customers through IPL’s fuel-related cost recovery mechanism. Credits on IPL’s customers’ bills are expected to be offset by a reduction in income tax expense. (b) In December 2023, the PSCW issued an order authorizing an annual base rate increase of $60 million for WPL’s retail electric customers, covering the 2025 forward-looking Test Period, which reflects revenue requirement impacts of increasing electric rate base including investments in solar generation and energy storage. (c) Sales for resale bulk power and other revenues increased primarily due to higher prices for electricity and capacity sold by IPL and WPL to MISO wholesale energy markets. These changes were largely offset by changes in electric fuel-related costs. (d) WPL’s cost recovery mechanism for retail fuel-related expenses supports deferrals of amounts that fall outside an approved fuel monitoring range of forecasted fuel-related expenses determined by the PSCW each year. The difference between revenue collected and actual fuel-related expenses incurred within the fuel monitoring range increases or decreases Alliant Energy’s and WPL’s electric utility revenues. WPL estimates the increase (decrease) to electric utility revenues from amounts within the fuel monitoring range were approximately $4 million and $(4) million in 2025 and 2024, respectively. Gas Utility Revenue Variances - The following items contributed to increased (decreased) gas utility revenues for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher revenues due to changes in gas costs (Refer to Cost of Gas Sold Expense Variances below) $40 $8 $32 Estimated changes in sales volumes caused by temperatures 17 8 9 Higher revenue requirements (a) 6 6 — Lower 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) ) (8) (8) — Other 5 1 4 $60 $15 $45 (a) In September 2024, the IUC issued an order authorizing an annual base rate increase of $10 million for IPL’s retail gas customers, for the October 2024 through September 2025 forward-looking Test Period. Rate changes were effective October 1, 2024, which reflect revenue requirement impacts of increasing gas rate base. 33 Table of Contents Electric Production Fuel and Purchased Power Expenses Variances - The following items contributed to (increased) decreased electric production fuel and purchased power expenses for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher electric production fuel costs (a) ($63) ($41) ($22) Changes in WPL refunds/collections of previous over-/under-collection of retail electric fuel-related costs (offset in electric utility revenue) (Refer to Note 1(g) ) (43) — (43) Changes in regulatory recovery of retail electric fuel-related costs (Refer to Note 1(g) ) (6) 7 (13) (Higher) lower purchased power expense (b) (5) 20 (25) Other 3 — 3 ($114) ($14) ($100) (a) Electric production fuel costs increased primarily due to higher coal volumes due to higher dispatch of coal-fired EGUs and higher natural gas prices, partially offset by lower natural gas volumes due to lower dispatch of natural gas-fired EGUs. (b) Purchased power expense increased primarily due to higher prices for electricity purchased by WPL, partially offset by lower volumes of electricity purchased at IPL. Electric Transmission Service Expense Variances - The following items contributed to (increased) decreased electric transmission service expense for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Changes in regulatory recovery for the difference between actual electric transmission service costs and those costs used to determine rates (Refer to Note 1(g) ) $15 $4 $11 Other (primarily due to changes in transmission service costs provided by third parties) (27) (9) (18) ($12) ($5) ($7) Cost of Gas Sold Expense Variances - The following items contributed to (increased) decreased cost of gas sold expense for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Changes in retail gas volumes and natural gas prices ($43) ($12) ($31) Changes in the regulatory recovery of gas costs (Refer to Note 1(g ) ) 4 5 (1) ($39) ($7) ($32) Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher generation and energy delivery expenses ($26) ($8) ($18) Higher incentive compensation expense (20) (11) (9) Asset valuation charge for Alliant Energy’s non-utility business in 2025 (Refer to Note 17) (16) — — Development costs for new generation (14) (6) (8) Higher energy efficiency expense at IPL (mostly offset by higher revenues) (11) (11) — Restructuring and voluntary employee separation charges in 2024 (excluding payroll taxes) (Refer to Note 12(a) ) 27 13 12 ARO charge for steam assets at IPL in 2024 (Refer to Note 13 ) 20 20 — Other (24) (12) (4) ($64) ($15) ($27) 34 Table of Contents Other Future Considerations - In addition to items discussed in this report, the following key items could impact Alliant Energy’s, IPL’s and WPL’s future financial condition or results of operations: • Financing Plans - Alliant Energy currently expects to issue up to $2.4 billion of common stock in aggregate from 2026 through 2029 through the distribution agreement that was executed in May 2025, its Shareholder Direct Plan (up to $25 million in common stock annually) and additional future equity offerings. Refer to Note 7 for discussion of common stock issuances by Alliant Energy in 2025 and Alliant Energy’s at-the-market offering program. In 2026, IPL and WPL currently expect to issue up to $500 million and $300 million, respectively, of long-term debt, and AEF and/or Alliant Energy at the parent company level expect to issue up to $400 million of long-term debt in aggregate. AEF and Alliant Energy at the parent company level have $500 million ($300 million term loan was retired in January 2026) and $575 million, respectively, of long-term debt maturing in 2026. • Common Stock Dividends - Alliant Energy announced a 5% increase in its targeted 2026 annual common stock dividend to $2.14 per share, which is equivalent to a quarterly rate of $0.535 per share, beginning with the February 2026 dividend payment. The timing and amount of future dividends is subject to approval of quarterly dividend declarations from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors. • Higher Earnings on Increasing Rate Base - Alliant Energy and WPL currently expect increases in electric utility and gas utility revenues in 2026 compared to 2025 due to impacts from increasing revenue requirements related to investments in the utility business (refer to “ Rate Matters ” for further discussion). Additionally, Alliant Energy and IPL currently expect electric utility revenues to increase in 2026 compared to 2025 due to the expiration of tax benefit rider credits in 2025. Furthermore, Alliant Energy, IPL and WPL currently expect a decrease in the effective income tax rate in 2026 compared to 2025 due to additional renewable tax credits from renewable generation and energy storage projects placed in service in 2025 and/or expected to be placed in service in 2026. A majority of the differences between actual renewable tax credits and renewable tax credits used to determine rates are recorded in regulatory assets or regulatory liabilities on the balance sheets until they are reflected in future billings to customers. Investment tax credits resulting from IPL energy storage projects placed in service in 2025 and/or expected to be placed in service in 2026 may be utilized to offset any revenue deficiency on an annual basis up to the earnings sharing mechanism threshold included in IPL’s retail electric rate review settlement agreement. • Sales Trends - Alliant Energy, IPL and WPL currently expect an increase in retail electric sales in 2026 compared to 2025 driven by expected load growth from new customers who currently expect to build data centers in IPL’s and WPL’s service territories. Refer to “ Growing Customer Demand ” for further discussion. • Other Operation and Maintenance Expenses - Alliant Energy, IPL and WPL currently expect an increase in other operation and maintenance expenses in 2026 compared to 2025 largely due to higher generation maintenance and energy delivery expenses. • Depreciation and Amortization Expense - Alliant Energy, IPL and WPL currently expect an increase in depreciation and amortization expense in 2026 compared to 2025 due to capital projects placed in service in 2025 and 2026. • Interest Expense - Alliant Energy, IPL and WPL currently expect an increase in interest expense in 2026 compared to 2025 due to financings completed in 2025 and planned in 2026 as discussed above. • Allowance for Funds Used During Construction - Alliant Energy, IPL and WPL currently expect an increase in AFUDC in 2026 compared to 2025 largely due to changes in CWIP balances related to construction activity on capital projects. CUSTOMER INVESTMENTS Alliant Energy’s, IPL’s and WPL’s strategic priorities include making significant customer-focused investments toward reliable, resilient and sustainable customer energy solutions. These priorities include: Resource Planning Alliant Energy’s current resource plan guides the addition of resources in Iowa and Wisconsin to meet customer demand for energy solutions that are affordable, safe, reliable, and responsibly delivered. Over the next five years, Alliant Energy currently plans to develop and/or acquire new generation investments to add flexibility with evolving load growth, including approximately 1,600 MW of new natural gas resources, approximately 1,000 MW of new energy storage, approximately 1,300 MW of new renewable generation, improvements of approximately 410 MW at existing natural gas-fired EGUs, and refurbishments at approximately 450 MW of existing wind farms. Alliant Energy is currently evaluating the impact of potential additional demand from large load growth customers and MISO’s seasonal resource adequacy requirements on its resource plans and will update these generation investment plans as needed in the future. Estimated capital expenditures for these planned projects for 2026 through 2029 are included in the “Generation” section in the construction and acquisition table in “ Liquidity and Capital Resources .” Information on IPL’s and WPL’s regulatory filings and/or approvals for future generation and energy storage projects, as well as recently completed projects, are as follows: WPL’s Generation and Energy Storage Projects - New Solar - In 2022 through 2024, WPL completed 1,089 MW of new solar generation projects in Wisconsin. Refer to Note 3 for discussion of the construction costs associated with these projects. New Energy Storage - In 2023, the PSCW issued orders authorizing WPL to construct, own and operate energy storage at the Grant County (100 MW) and Wood County (75 MW) solar projects in Wisconsin, which were placed in service in July and October 2025, respectively, and at the Edgewater Generation Station in Wisconsin (approximately 99 MW), which is currently expected to be placed in service in 2026. 35 Table of Contents In July 2024, the U.S. Department of Energy Office of Electricity - formerly administered by the Office of Clean Energy Demonstrations - awarded WPL’s Columbia Energy Storage Project, an approximately 20 MW compressed CO2-based long-duration energy storage system at the Columbia Energy Center site, up to approximately $30 million in grant funding during construction of the project. In June 2025, WPL received an order from the PSCW authorizing the construction of the energy storage system. Any grant proceeds are expected to reduce the cost of the project for WPL’s customers. In February 2025, WPL filed a CA application with the PSCW for approval to construct a 2 billion cubic feet, or 25 million gallon, liquified natural gas facility in Rock County, Wisconsin. A decision from the PSCW is currently expected in the second quarter of 2026. New Wind - In April 2025, WPL filed a CA application with the PSCW for approval to construct, own and operate the Bent Tree North EGU, an approximately 153 MW wind farm. A decision from the PSCW is currently expected in the second quarter of 2026. In January 2026, WPL filed a CA application with the PSCW for approval to acquire, construct, own and place into service an approximately 277 MW wind farm in Columbia County, Wisconsin. The CA application also included a request for approval of an agreement between WPL and an affiliated subsidiary of AEF, under which WPL would acquire wind development assets from the affiliate. A decision from the PSCW is currently expected in the first quarter of 2027. New Natural Gas-fired Electric Generation - In April 2025, the PSCW issued an order authorizing WPL to construct, own and operate a 17.5 MW natural gas-fired EGU using Reciprocating Internal Combustion Engine (RICE) technology, at the site of its Riverside Energy Center. Existing Natural Gas-Fired Electric Generating Unit Improvements - In April 2024, the PSCW issued orders authorizing WPL to construct improvements at the existing natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility. In 2025, the Neenah Unit 1 and Sheboygan Falls Unit 1 advanced gas path projects were completed, which increased the efficiency and capacity at each of these EGUs. The Neenah Unit 2 and Sheboygan Falls Unit 2 advanced gas path projects are expected to be completed in the second quarter of 2026. Existing Wind Farm Refurbishment - In May 2025, the PSCW issued an order authorizing WPL to refurbish the Bent Tree wind farm. In December 2025, the PSCW issued an order authorizing WPL to refurbish the Forward Wind Energy Center. IPL’s Generation and Energy Storage Projects - New Solar - In 2024, IPL completed 400 MW of new solar generation projects in Iowa. New Energy Storage - In 2024, IPL received approval from the IUC to construct, own and operate up to 99 MW of energy storage, which was placed in service in November 2025 at the site of its Wever solar facility. In July 2025, the IUC issued an order authorizing IPL to construct, own and operate up to 150 MW of energy storage at the site of its retired Lansing Generating Station. In August 2025, the IUC issued an order authorizing IPL to construct, own and operate up to 75 MW of energy storage at the site of its Golden Plains wind farm. In September 2025, the IUC issued an order authorizing IPL to construct, own and operate up to 75 MW of energy storage at the site of its Whispering Willow - North wind farm. New Natural Gas-fired Electric Generation - In June 2025, IPL received approval from the IUC to construct, own and operate the Cedar River Generating Station, a 94 MW natural gas-fired EGU using RICE technology, at the site of IPL’s Prairie Creek Generation Station. In December 2025, IPL received an order from the IUC for approval to construct, own and operate an approximately 720 MW simple-cycle natural gas-fired EGU at the site of its Marshalltown Generating Station, known as the Bobcat Energy Center. In January 2026, IPL received approval from the IUC to construct, own and operate a 94 MW natural gas-fired EGU using RICE technology at the site of its Burlington Generating Station. New Wind - In July 2025, IPL filed for advance rate-making principles with the IUC for up to 1,000 MW of new wind generation in Iowa. The advance rate-making principles filing included requests for a fixed cost cap of $3,020/kilowatt, including AFUDC and transmission upgrade costs among other costs, and a return on common equity of 11.25%. In December 2025, IPL reached a non-unanimous settlement agreement with the Iowa Office of Consumer Advocate and others, subject to IUC approval, for up to 1,000 MW nameplate capacity of wind generation with a cost cap of $3,020/kW including AFUDC and transmission costs. IPL’s return on common equity will be the same as other assets without advance rate-making principles for purposes of setting future rates and IPL’s blended return on common equity, which will be updated each year, will be used for IPL’s retail electric earnings sharing mechanism calculation. A decision from the IUC is currently expected in the first half of 2026. Existing Wind Farm Refurbishment - In 2024, IPL completed the refurbishment of the existing Franklin County wind farm in Iowa. IPL currently expects the refurbishment of the existing Whispering Willow - East wind farm to be completed in 2026. These projects are eligible for production tax credits under the Inflation Reduction Act of 2022. WPL’s West Riverside Natural Gas-fired Generating Station - In 2020, WPL completed the construction of West Riverside, a 723 MW natural gas-fired combined-cycle EGU in Beloit, Wisconsin. WPL entered into agreements with neighboring utilities and electric cooperatives that provide each of them options to purchase a partial ownership interest in West Riverside. The purchase price for such options is based on the ownership interest acquired and the net book value of West Riverside on the date of the purchase. The timing and ownership amount of the options are as follows: 36 Table of Contents Counterparty Option Amount and Timing WEC Energy Group, Inc. (WEC) In 2023 and 2024, WEC acquired 200 MW in aggregate, pursuant to PSCW and FERC approval (a) Madison Gas and Electric Company (MGE) In 2023 and 2024, MGE acquired 50 MW in aggregate, pursuant to PSCW and FERC approval Electric cooperatives Approximately 60 MW were acquired in 2018 (a) WPL may exercise reciprocal options, subject to approval by the PSCW, to purchase up to 200 MW of any natural-gas combined-cycle EGU that WEC places in service prior to May 2030. Plant Retirements and Fuel Switching - The current strategy includes the retirement, or fuel switch from coal to natural gas, of various EGUs. Subsequent to December 31, 2025, IPL retired Prairie Creek Unit 1 and fuel switched Prairie Creek Unit 3 (65 MW in aggregate) to natural gas. WPL currently plans to continue coal operations at Edgewater Unit 5 (414 MW) and Columbia Units 1 and 2 (595 MW in aggregate) at least through 2029, as well as evaluate the potential conversion of these EGUs to natural gas. Alliant Energy, IPL and WPL are working with MISO, state regulatory commissions and other regulatory agencies, as required, to determine the timing of these actions, which are subject to change depending on operational, regulatory, market and other factors. Refer to Note 3 for additional details on Columbia Units 1 and 2. Environmental Stewardship - Alliant Energy’s environmental stewardship is focused on the implementation of a responsible energy strategy. Alliant Energy’s strategy and business plans consider the transition to a low-carbon economy as one of several factors driving transformation of the energy industry. Alliant Energy’s journey toward carbon reductions includes long-term voluntary goals to eliminate all coal-fired EGUs from its generating fleet by 2040 and aspiring to achieve net-zero GHG emissions from its utility operations by 2050. Alliant Energy’s voluntary Environmental Stewardship goals previously included interim 2030 environmental-related goals for GHG emissions, utility water supply, and electrifying owned light-duty fleet vehicles. In the first quarter of 2026, Alliant Energy decided to remove the interim 2030 voluntary environmental-related goals while remaining focused on its long-term voluntary goals. This decision was made due to a combination of factors, including the need to serve its customers with affordable, safe, and reliable energy, resource adequacy requirements, and increasing customer energy needs. Alliant Energy’s voluntary environmental stewardship goals may be revised, or their achievement may be delayed, based on increasing customer energy needs, reliability and resource adequacy requirements, and tax policy changes. The ability to achieve these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories. These goals are not meant to be considered guidance. Other Customer-focused Investments Electric and Gas Distribution Systems - Customer-focused investments include replacing, modernizing and upgrading infrastructure in the electric and gas distribution systems. Electric system investments will focus on areas such as improving reliability and resiliency with more underground electric distribution and upgrades including automation and enabling distributed energy resources. Gas system investments will focus on pipeline replacement to modernize Alliant Energy’s gas distribution systems and pipeline expansion to support reliability and economic development. Estimated capital expenditures for expected and current electric and gas distribution infrastructure projects for 2026 through 2029 are included in the “Electric and gas distribution systems” lines in the construction and acquisition expenditures table in “ Liquidity and Capital Resources .” Fiber Optic Telecommunication Network - Alliant Energy installed fiber optic routes between its facilities to enhance its communications network to improve resiliency and reliability of, and enable and strengthen, the integrated grid network focused on less densely populated rural areas. Gas Pipeline Expansion - IPL and WPL currently expect to make investments to extend various gas distribution systems to provide natural gas to unserved or underserved areas in their service territories. Additionally, IPL expects to make investments in gas pipelines to serve new natural gas generating facilities. Gas Pipeline Safety - The Pipeline and Hazardous Materials Safety Administration published various final rules from 2019 through 2024 that updated safety requirements for gas transmission pipelines, and updated procedures were implemented to address these rules. Plans to address certain requirements for specific pipelines were developed and implemented. The majority of identified remediation efforts have been completed with remaining items to be completed by July 2035. In response to these rule changes, Alliant Energy, IPL and WPL have been assessing, testing and modifying certain of IPL’s and WPL’s pipelines, and updating practices for assessment and operation of all IPL and WPL pipelines. Alliant Energy, IPL, and WPL also continue to evaluate the impact of these final rules and resulting remediation plans on their financial condition and results of operations. Technology - Alliant Energy, IPL and WPL currently plan to make investments in technology to enhance productivity and efficiency through automation and customer self-service. Estimated capital expenditures for expected and current technology projects for 2026 through 2029 are included in the “Other” line in the construction and acquisition expenditures table in “ Liquidity and Capital Resources .” 37 Table of Contents RATE MATTERS Rate Reviews Retail Base Rate Filings - Base rate changes reflect both returns on additions to infrastructure and recovery of changes in costs incurred or expected to be incurred to provide electric and gas service to retail customers. Given that a portion of the rate changes will offset changes in costs, revenues from rate changes should not be expected to result in an equal change in net income for either IPL or WPL. IPL’s Retail Electric and Gas Rate Reviews (October 2024 Through September 2025 Forward-looking Test Period) - In September 2024, the IUC issued an order for IPL’s retail electric and gas rate reviews for the October 2024 through September 2025 forward-looking Test Period with rate changes effective October 1, 2024. Key drivers for the rate review included revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation, as well as updated depreciation rates and certain incremental costs incurred resulting from the 2020 derecho windstorm. The IUC’s order included the following provisions: • Annual retail electric base rate increase of $185 million, with customers receiving partially offsetting credits for the first 12 months through a tax benefit rider totaling $52 million and $16 million in 2025 and 2024, respectively, and a subsequent retail electric base rate moratorium through September 2029; • During the moratorium, IPL may request updated rates if its actual return on common equity is 100 or more basis points below the authorized return on common equity for a single calendar year or 50 or more basis points below the authorized return on common equity for two consecutive years, and/or if a material change in laws or regulations causes the moratorium to become unsustainable; • Annual retail gas base rate increase of $10 million; • Electric earnings sharing mechanism beginning in calendar year 2025, where IPL would apply excess earnings to the remaining net book value of IPL’s highest earning asset with advance ratemaking principles (currently the Emery Generation Station) based on its authorized return on common equity as follows; Threshold Above Authorized Return on Common Equity Sharing First 50 basis points 75% customers, 25% IPL >50 to 100 basis points 50% customers, 50% IPL >100 to 150 basis points 25% customers, 75% IPL >150 basis points 100% customers • Investment tax credits resulting from renewable generation and energy storage projects 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 revenue deficiency in future years; • Creation of an individual customer rate tariff, which would allow IPL to attract new load growth to its service territory; • Electric distribution system investment cap not to exceed $900 million in aggregate or $325 million in any given year from 2026 through 2029, with certain exceptions; • IPL to retain renewable production tax credits from new generation resources not included in base rates and the repowering of existing wind farms, including the Franklin County wind farm refurbishment, as well as retain energy margins for new generation resources and energy storage; • Discontinuation of the renewable energy rider; and • A return of the remaining net book value of the Lansing Generating Station; however, the IUC’s order does not include a return on the remaining net book value of Lansing, resulting in Alliant Energy and IPL recording a pre-tax non-cash charge of $60 million to “Asset valuation charge for IPL’s Lansing Generating Station” in their income statements in 2024. IPL filed a subsequent proceeding with the IUC in December 2025 for its October 2024 through September 2025 forward-looking Test Period retail electric and gas rate reviews, which compared actual revenues and costs to those initially forecasted by IPL. IPL currently does not expect any rate adjustments from this subsequent proceeding. WPL’s Retail Electric and Gas Rate Reviews (2026/2027 Forward-looking Test Period) - In December 2025, the PSCW issued an order authorizing annual base rate increases of $69 million and $7 million for WPL’s retail electric and gas customers, respectively, effective January 1, 2026, for the 2026 forward-looking Test Period. The PSCW’s order also authorized WPL to implement an additional $75 million and $5 million increase in annual rates for its retail electric and gas customers, respectively, effective January 1, 2027, for the 2027 forward-looking Test Period. The key drivers for the annual base rate increases include revenue requirement impacts of increasing electric and gas rate base, including wind refurbishment projects, energy storage, existing natural gas-fired EGU improvements, solar generation costs incurred that exceed the construction cost estimates previously approved by the PSCW (refer to Note 3 for further discussion), and electric and gas distribution investments. The order extends, with certain modifications, an earnings sharing mechanism through 2027. Under the earnings sharing mechanism, WPL will defer a portion of its earnings if its annual regulatory return on common equity exceeds 10.05% during the 2026/2027 Test Period. WPL must defer 50% of its excess earnings between 10.05% and 10.55%, and 100% of any excess earnings above 10.55%. The PSCW also authorized an AFUDC applied to 100% of CWIP balances related to construction activity on capital projects requiring PSCW approval and are impacted by federal law changes. 38 Table of Contents Rate Review Details - Details related to IPL’s and WPL’s key jurisdictions were as follows: Average Authorized Return Common Equity Regulatory Rate Base on Common Component of Regulatory Effective Body (in millions) Equity (a) Capital Structure Date IPL Retail Electric (October 2024-September 2025 Test Period) (b) Marshalltown IUC $484 11.00% 51.0% 10/1/2024 Emery IUC 90 12.23% 51.0% 10/1/2024 Whispering Willow - East IUC 124 11.70% 51.0% 10/1/2024 Wind IUC 1,218 11.00% 51.0% 10/1/2024 Solar IUC 511 10.25% 51.0% 10/1/2024 Other (c) IUC 4,852 9.34% 51.0% 10/1/2024 IPL Retail Gas (October 2024-September 2025 Test Period) (b) IUC 630 9.65% 51.0% 10/1/2024 IPL Wholesale Electric FERC 177 10.97% 50.0% 1/1/2025 WPL Retail Electric and Gas Electric (2026 Test Period) (d) PSCW 6,234 9.80% 54.5% 1/1/2026 Gas (2026 Test Period) (d) PSCW 558 9.80% 54.5% 1/1/2026 WPL Wholesale Electric FERC 550 10.90% 55.0% 1/1/2025 (a) Authorized returns on common equity may not be indicative of actual returns earned or projections of future returns. (b) Average rate base amounts reflect IPL’s allocated retail share of rate base and do not include CWIP and were calculated using a forecasted 13-month average for the test period. (c) Average rate base amounts include assets that do not have advance rate-making principles (9.65% return on common equity), production tax credits carryforwards for 1,000 MW of wind generating facilities placed in service in 2019 and 2020 (5% return on common equity), as well as the portion of Whispering Willow - East that does not earn a return on investment. (d) Average rate base amounts reflect WPL’s allocated retail share of rate base and do not include CWIP or a cash working capital allowance, and were calculated using a forecasted 13-month average for the test period. The PSCW provides a return on selected CWIP and a cash working capital allowance by adjusting the percentage return on rate base. LEGISLATIVE MATTERS Tax Legislation In August 2022, the Inflation Reduction Act of 2022 was enacted. The most significant provisions of the legislation for Alliant Energy, IPL and WPL relate to a 10-year extension of tax credits for clean energy projects, a new production tax credit for eligible solar projects, a standalone investment tax credit for energy storage projects, and the right to transfer renewable tax credits generated after 2022 to other corporate taxpayers. The legislation also established a requirement for corporations with income over $1 billion to pay a 15% minimum tax; however, Alliant Energy is currently below this income level. Alliant Energy, IPL and WPL are utilizing various provisions of the Inflation Reduction Act of 2022 to enhance the tax benefits expected from their current and planned renewable generation and energy storage projects, including transferring tax credits from such projects to other corporate taxpayers. Refer to Note 1(c) for discussion of the transfer of renewable tax credits to other corporate taxpayers. In July 2025, the One Big Beautiful Bill Act was enacted, which modified various clean energy tax credits under the Inflation Reduction Act of 2022, including production tax credits and investment tax credits. The most significant provisions of the new legislation for Alliant Energy, IPL, and WPL relate to the accelerated phase out of clean energy tax credits for eligible wind and solar projects for which construction begins more than 12 months after the enactment date or for projects placed in service after 2027, and restricted access to clean energy tax credits for projects that begin construction after 2025 and receive impermissible amounts of construction support from entities with ties to certain foreign countries, including China. Additionally, in July 2025, the Presidential Administration directed the U.S. Department of the Treasury to strictly enforce the termination of clean energy tax credits, including issuing new and revised guidance in August 2025, to ensure that requirements concerning the beginning of construction are not circumvented. Refer to “ Customer Investments ” for discussion of Alliant Energy’s, IPL’s and WPL’s current plans to develop and/or acquire new renewable generation and energy storage projects. Alliant Energy, IPL and WPL currently expect these planned renewable generation and energy storage projects would continue to be eligible for clean energy tax credits. If these renewable generation and energy storage projects do not begin construction within the anticipated timeframes or fail to meet other eligibility requirements, the amount of clean energy tax credits could be significantly reduced, which could adversely impact Alliant Energy’s, IPL’s and WPL’s financial condition and results of operations. Refer to Note 1 1 for discussion of Iowa tax reform enacted in 2022. 39 Table of Contents Economic Development In May 2024, the Major Economic Growth Attraction program was enacted in Iowa, which offers various tax incentives for up to two qualified businesses for certain large-scale projects with capital investments greater than $1 billion constructed on certified sites greater than 250 acres in Iowa. The most significant provision of this program for Alliant Energy encourages economic development in IPL’s service territory. Alliant Energy has various development-ready sites throughout Iowa, including the Prairie View Industrial Center Super Park in Ames, Iowa and the River City Industrial Center in Mason City, Iowa. In July 2023, legislation was enacted in Wisconsin, which creates a sales and use tax exemption for the sale of certain property for qualified data centers. The most significant provision of this legislation for Alliant Energy encourages economic development in WPL’s service territory. Advance Rate-making Principles In May 2024, legislation was enacted in Iowa related to the advance rate-making principles for certain generation and energy storage investments located in Iowa. The most significant provisions of this legislation for Alliant Energy would allow IPL to include energy storage and nuclear-fired generation projects in the advance rate-making principles request process prior to making these investments in Iowa, and require IPL to obtain a GCU Certificate from the IUC in order to construct energy storage projects. LIQUIDITY AND CAPITAL RESOURCES Overview - Alliant Energy, IPL and WPL expect to maintain adequate liquidity to operate their businesses and implement their strategy as a result of operating cash flows generated by their utility business, and available capacity under a single revolving credit facility and IPL’s sales of accounts receivable program, supplemented by periodic issuances of long-term debt and Alliant Energy equity securities. As summarized below, Alliant Energy, IPL and WPL believe they have the ability to generate and obtain adequate amounts of cash to meet their requirements and plans for cash in the next 12 months and beyond. Liquidity Position - At December 31, 2025, Alliant Energy had $556 million of cash and cash equivalents, $1,212 million ($550 million at the parent company, $262 million at IPL and $400 million at WPL) of available capacity under the single revolving credit facility and no available capacity at IPL under its sales of accounts receivable program. Capital Structure - Alliant Energy, IPL and WPL plan to maintain debt-to-total capitalization ratios that are consistent with investment-grade credit ratings, as well as maintain capital structures consistent with the authorized levels approved by IPL’s and WPL’s regulators. The following table shows financial capital structures as of December 31, 2025, as well as an adjusted capitalization structure that Alliant Energy believes is consistent with how a majority of the rating agencies currently view its junior subordinated notes: Alliant Energy IPL WPL (in millions) Actual Adjusted (a) Actual Actual Common equity $7,334 $7,697 $4,844 $4,375 Long-term debt (including current maturities) 12,028 11,665 4,680 3,669 Short-term debt 88 88 88 — Total capitalization $19,450 $19,450 $9,612 $8,044 Total debt $12,116 $11,753 $4,768 $3,669 Ratio of debt to total capitalization 62 % 60 % 50 % 46 % (a) The long-term debt component of Alliant Energy’s financial capital structure includes junior subordinated notes classified as “Long-term debt, net” on Alliant Energy’s balance sheet (refer to Note 8(b) for additional information). The adjusted presentation at December 31, 2025 attributes 50% of the junior subordinated notes to common equity and 50% to long-term debt, to align with the debt-to-capital ratio used by the majority of rating agencies. The non-GAAP adjusted presentation reflecting this treatment is useful and relevant to investors in understanding how management and the rating agencies evaluate Alliant Energy’s capital structure. Alliant Energy, IPL and WPL intend to manage their capital structures and liquidity positions in such a way that facilitates their ability to raise funds reliably and at reasonable terms and conditions, while maintaining capital structures consistent with those approved by regulators. In addition to capital structures, other important factors used to determine the characteristics of future financings include financial coverage ratios, capital spending plans, regulatory orders and rate-making considerations, levels of debt and equity imputed by rating agencies, market conditions, the impact of tax initiatives and legislation, and any potential proceeds from asset sales. The PSCW factors certain imputed debt adjustments, including certain lease obligations, in establishing a regulatory capital structure as part of WPL’s retail rate reviews. The IUC does not make any explicit adjustments for imputed debt in establishing capital ratios used in determining customer rates, although such adjustments are considered by IPL in recommending an appropriate capital structure. Debt imputations by rating agencies include, among others, AROs, pension and OPEB obligations, the sales of accounts receivable program and certain lease obligations. 40 Table of Contents Credit and Capital Markets - Alliant Energy, IPL and WPL maintain a single revolving credit facility to provide backstop liquidity to their commercial paper programs, and ensure a committed source of liquidity in the event the commercial paper market becomes disrupted. In addition, IPL maintains a sales of accounts receivable program as an alternative financing source; however, if customer arrears were to exceed certain levels, IPL’s access to the program may be restricted. Primary Sources and Uses of Cash - Alliant Energy’s most significant source of cash is from electric and gas sales to IPL’s and WPL’s customers. Cash from these sales reimburses IPL and WPL for prudently-incurred expenses to provide service to their utility customers and generally provides IPL and WPL a return of and a return on the assets used to provide such services. Capital needed to retire debt and fund capital expenditures related to large strategic projects is expected to be met primarily through external financings. Cash Flows - Selected information from the cash flows statements was as follows (in millions): Alliant Energy IPL WPL 2025 2024 2025 2024 2025 2024 Cash, cash equivalents and restricted cash, January 1 $81 $63 $29 $53 $51 $7 Cash flows from (used for): Operating activities 1,169 1,167 286 357 836 761 Investing activities (1,896) (1,547) (859) (684) (827) (724) Financing activities 1,202 398 551 303 (23) 7 Net increase (decrease) 475 18 (22) (24) (14) 44 Cash, cash equivalents and restricted cash, December 31 $556 $81 $7 $29 $37 $51 Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher collections from IPL’s and WPL’s retail electric and IPL’s gas base rate increases $339 $277 $62 Changes in income taxes paid/received (a) 69 (36) 95 Increased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales 62 35 27 Timing of WPL’s fuel-related cost recoveries from retail electric customers 56 — 56 Lower revenues at IPL due to credits on customers’ bills related to production tax credits through its fuel-related cost recovery mechanism (122) (122) — Changes in interest payments (66) (43) (13) Changes in the sales of accounts receivable at IPL (51) (51) — Lower revenues at IPL due to credits on customers’ bills through the tax benefit rider (36) (36) — Changes in levels of materials and supplies (31) (8) (23) Restructuring and voluntary employee separation payments in 2025 (25) (11) (12) Lower revenues at IPL due to discontinuation of renewable energy rider in 2024 (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 (primarily due to other changes in working capital) (147) (30) (117) $2 ($71) $75 (a) Refer to the cash flows statements for details of renewable tax credits transferred to other corporate taxpayers in 2024 and 2025. Income Tax Payments and Receipts - Income tax (payments) receipts were as follows (in millions): 2025 2024 IPL $139 $175 WPL 109 14 Other subsidiaries 18 8 Alliant Energy $266 $197 Alliant Energy, IPL and WPL currently do not expect to make any significant federal income tax payments over the next few years based on their current credit carryforward positions; however, some tax payments and receipts may occur for state taxes and between consolidated group members (including IPL and WPL) under the tax sharing agreement between Alliant Energy and its subsidiaries. Refer to Note 1 1 for discussion of the carryforward positions. 41 Table of Contents As discussed in “ Legislative Matters ,” the Inflation Reduction Act of 2022 provides the right to transfer renewable tax credits to other corporate taxpayers. Refer to the cash flows statements and Note 1 (c) for details of renewable tax credits transferred to other corporate taxpayers. Alliant Energy, IPL and WPL currently intend to transfer all eligible renewable tax credits in the future. Pension Plan Contributions - Alliant Energy, IPL and WPL currently expect to make $23 million, $3 million and $13 million of pension plan contributions in 2026, respectively, based on the funded status and assumed return on assets for each plan as of the December 31, 2025 measurement date. Refer to Note 1 2 (a) for discussion of pension plan contributions in 2025 and the current funded levels of pension plans. Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL (Higher) lower utility construction and acquisition expenditures (a) ($225) ($249) $24 Proceeds from sales of partial ownership interests in West Riverside in 2024 (123) — (123) Changes in the amount of cash receipts on sold receivables 35 35 — Other (36) 39 (4) ($349) ($175) ($103) (a) Largely due to higher expenditures for IPL’s energy storage and gas generation and IPL’s and WPL’s refurbishment of existing wind farms, partially offset by lower expenditures for IPL’s and WPL’s solar generation and WPL’s energy storage. Construction and Acquisition Expenditures - Construction and acquisition expenditures and financing plans are reviewed, approved and updated as part of the strategic planning process. Changes may result from a number of reasons, including changes in expected load growth, regulatory requirements, changing legislation, not obtaining favorable and acceptable regulatory approval on certain projects, changing costs of projects due to market conditions and the impact of tariffs, improvements in technology, and improvements to ensure resiliency and reliability of the electric and gas distribution systems. Refer to “ Rate Matters ” for discussion of an electric distribution system investment cap included in IPL’s rate review settlement agreement, which was approved by the IUC in September 2024. Alliant Energy, IPL and WPL have not yet entered into contractual commitments relating to the majority of their anticipated future construction and acquisition expenditures. As a result, they have some discretion with regard to the level and timing of these expenditures. Construction and acquisition expenditures for 2026 through 2029 are currently anticipated as follows (in millions), which are focused on adding renewable generation and energy storage projects and dispatchable gas generation projects to meet growing customer demand for electricity, including expected future data center growth from currently executed electric service agreements, and strengthening the resiliency and reliability of the electric and gas distribution systems. Alliant Energy, IPL and WPL are currently evaluating the impacts of tariffs, recently enacted legislation and additional potential demand from large load growth customers on their resource plans, and will update their anticipated construction and acquisition expenditures as needed in the future. Cost estimates represent Alliant Energy’s, IPL’s and WPL’s portion of construction expenditures and exclude AFUDC and capitalized interest, if applicable. Refer to “ Customer Investments ” for further discussion of certain key utility business projects impacting construction and acquisition plans, and the related regulatory filings. Alliant Energy IPL WPL 2026 2027 2028 2029 2026 2027 2028 2029 2026 2027 2028 2029 Generation: Renewables and energy storage projects $1,055 $1,035 $1,465 $1,495 $625 $830 $625 $1,400 $360 $325 $840 $95 Gas projects 970 1,515 1,135 460 660 1,095 890 400 280 420 245 60 Other 175 125 120 105 70 75 50 45 105 50 70 60 Distribution: Electric systems 545 540 565 605 275 260 265 270 270 280 300 335 Gas systems 145 135 105 105 80 70 40 40 65 65 65 65 Other 240 230 235 295 45 45 40 60 40 35 35 55 $3,130 $3,580 $3,625 $3,065 $1,755 $2,375 $1,910 $2,215 $1,120 $1,175 $1,555 $670 West Riverside Options - WPL entered into agreements with neighboring utilities that provided them options to purchase a partial ownership interest in West Riverside. Upon exercise of such options and the resulting sales, WPL received proceeds from the sales in 2024. Refer to “ Customer Investments ” for additional information. Renewable Tax Credits - IPL and WPL started construction in 2024 and 2025, and currently expect to start construction in the first half of 2026, of certain renewable and energy storage projects, with the intention of preserving the qualification of any renewable tax credits associated with these projects. 42 Table of Contents Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for 2025 compared to 2024 (in millions): Alliant Energy IPL WPL Higher (lower) net proceeds from issuance of long-term debt $857 $245 ($1) Lower payments to retire long-term debt 509 200 — Net changes in the amount of commercial paper outstanding (553) (12) (48) Higher common stock dividends (29) (159) (11) Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy — (40) 25 Other 20 14 5 $804 $248 ($30) FERC and Public Utility Holding Company Act Financing Authorizations - Under the Public Utility Holding Company Act of 2005, FERC has authority over the issuance of utility securities, except to the extent that a public utility’s primary state regulatory commission has retained jurisdiction over such matters. FERC currently has authority over the issuance of securities by IPL. FERC does not have authority over the issuance of securities by Alliant Energy, WPL, AEF or Corporate Services. In January 2026, IPL received authorization from FERC to issue securities in 2026 and 2027 as follows (in millions): Initial Authorization Long-term debt securities issuances in aggregate $2,500 Short-term debt securities outstanding at any time (including borrowings from its parent) 400 Preferred stock issuances in aggregate 300 State Regulatory Financing Authorizations - In March 2023, WPL received authorization from the PSCW to have up to $500 million of short-term borrowings and/or letters of credit outstanding at any time through the expiration date of WPL’s credit facility agreement. In January 2026, WPL received authorization from the PSCW to issue up to $2.8 billion of long-term debt securities in aggregate in 2026-2028. Shelf Registrations - Alliant Energy, IPL and WPL have current shelf registration statements on file with the SEC for availability to issue unspecified amounts of securities through December 2026. Alliant Energy’s shelf registration statement may be used to issue common stock, debt and other securities. IPL’s and WPL’s shelf registration statements may be used to issue preferred stock and debt securities. Common Stock Dividends - Payment of common stock dividends is subject to dividend declaration by Alliant Energy’s Board of Directors and is dependent upon, among other factors, regulatory limitations, earnings, cash flows, capital requirements and general financial condition of subsidiaries. Alliant Energy’s general long-term goal is to maintain a dividend payout ratio that is competitive with the industry average. Based on that, Alliant Energy’s goal is to maintain a dividend payout ratio of approximately 60% to 70% of consolidated earnings from continuing operations. Refer to “ Results of Operations ” for discussion of expected common stock dividends in 2026. Common Stock Issuances - Refer to Note 7 for discussion of common stock issuances by Alliant Energy in 2024 and 2025, and “ Results of Operations ” for discussion of expected issuances of common stock in 2026 through 2029. Short-term Debt - In December 2025, Alliant Energy, IPL and WPL amended and extended their single revolving credit facility agreement, which expires in December 2030 and is discussed in Note 8 (a) . There are currently 14 lenders that participate in the credit facility, with respective commitments ranging from $25 million to $130 million. Subject to certain conditions, Alliant Energy, IPL and WPL may exercise one extension option, which would extend the maturity date by one year. The credit facility has a provision to expand the facility size up to an additional $700 million, for a potential total commitment of $2 billion, subject to lender approval for Alliant Energy and subject to lender and regulatory approvals for IPL and WPL. The credit agreement contains customary events of default, including a cross-default provision that would be triggered if Alliant Energy or certain of its significant subsidiaries (including IPL and WPL) defaults on debt (other than non-recourse debt) totaling $100 million or more. IPL and WPL are subject to a similar cross-default provision with respect to their own respective consolidated debt. A default by Alliant Energy or its non-utility subsidiaries would not trigger a cross-default at IPL or WPL, nor would a default by either of IPL or WPL constitute a cross-default event for the other. If an event of default under the credit agreement occurs and is continuing, then the lenders may declare any outstanding obligations of the defaulting borrower under the credit agreement immediately due and payable. 43 Table of Contents The single credit facility agreement contains a financial covenant, which requires Alliant Energy, IPL and WPL to maintain certain debt-to-capital ratios in order to borrow under the credit facility. AEF’s term loan credit agreement contains a financial covenant, which requires Alliant Energy to maintain a certain debt-to-capital ratio in order to borrow under the term loan credit agreement. The required debt-to-capital ratios compared to the actual debt-to-capital ratios at December 31, 2025 were as follows: Alliant Energy IPL WPL Requirement, not to exceed 65% 65% 65% Actual 59% 50% 47% The debt component of the capital ratios includes, when applicable, long- and short-term debt (excluding non-recourse debt and hybrid securities (e.g., junior subordinated notes) to the extent the total carrying value of such hybrid securities does not exceed 15% of consolidated capital of the applicable borrower), finance lease obligations, certain letters of credit, guarantees of the foregoing and new synthetic leases. Unfunded vested benefits under qualified pension plans and sales of accounts receivable are not included in the debt-to-capital ratios. The equity component of the capital ratios excludes accumulated other comprehensive income (loss). Long-term Debt - Refer to Note 8 (b) for discussion of issuances and retirements of long-term debt in 2025, and “ Results of Operations ” for discussion of expected issuances and retirements of long-term debt in 2026. In 2024, IPL issued $350 million of 4.95% senior debentures due 2034 and $300 million of 5.45% senior debentures due 2054, a portion of which was used for the retirement of IPL’s $500 million 3.25% senior debentures, and the remainder was used for general corporate purposes. In 2024, WPL issued $300 million of 5.375% green bond debentures due 2034, and an amount equal to or in excess of the net proceeds was disbursed for the development and acquisition of its solar EGUs. In 2024, AEF entered into a $300 million variable rate term loan credit agreement, which amended and restated the term loan credit agreement that expired in March 2024, and retired the $300 million variable rate term loan credit agreement set forth therein. In 2024, AEF issued $375 million of 5.40% senior notes due 2027, and used the net proceeds to reduce Alliant Energy’s outstanding commercial paper and for general corporate purposes. Impact of Credit Ratings on Liquidity and Collateral Obligations - Ratings Triggers - The long-term debt of Alliant Energy and its subsidiaries is not subject to any repayment requirements as a result of explicit credit rating downgrades or so-called “ratings triggers.” However, Alliant Energy and its subsidiaries are parties to various agreements that contain provisions dependent on credit ratings. In the event of a significant downgrade, Alliant Energy or its subsidiaries may need to provide credit support, such as letters of credit or cash collateral equal to the amount of any exposure, or may need to unwind contracts or pay underlying obligations. In the event of a significant downgrade, management believes Alliant Energy, IPL and WPL have sufficient liquidity to cover counterparty credit support or collateral requirements under these various agreements. In addition, a downgrade in the credit ratings of Alliant Energy, IPL or WPL could also result in them paying higher interest rates in future financings, reduce flexibility with future financing plans, reduce their pool of potential lenders, increase their borrowing costs under existing credit facilities or limit their access to the commercial paper market. Credit ratings and outlooks as of the date of this report are as follows: Standard & Poor’s Ratings Services Moody’s Investors Service Alliant Energy: Corporate/issuer BBB+ Baa2 Commercial paper A-2 P-2 Senior unsecured long-term debt BBB N/A Outlook Stable Stable IPL: Corporate/issuer BBB+ Baa1 Commercial paper A-2 P-2 Senior unsecured long-term debt BBB+ Baa1 Outlook Stable Stable WPL: Corporate/issuer A- Baa1 Commercial paper A-2 P-2 Senior unsecured long-term debt A- Baa1 Outlook Stable Stable Standard & Poor’s Ratings Services and Moody’s Investors Service issued credit ratings of BBB+ and Baa2, respectively, for the senior notes issued by AEF in 2018, 2020, 2022, 2023 and 2024 (with Alliant Energy as guarantor). Credit ratings are not recommendations to buy or sell securities and are subject to change, and each rating should be evaluated independently of any other rating. Each of Alliant Energy, IPL or WPL assumes no obligation to update their respective credit ratings. Refer to N ote 1 4 for additional information on ratings triggers for commodity contracts accounted for as derivatives. 44 Table of Contents Off-Balance Sheet Arrangements - Special Purpose Entities - IPL maintains a Receivables Agreement whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The purchase commitment from the third party to which IPL sells its receivables expires in March 2026. In 2025 and 2024, IPL evaluated the third party that purchases IPL’s receivable assets under the Receivables Agreement and believes that the third party is a VIE; however, IPL concluded consolidation of the third party was not required. In addition, IPL’s sales of accounts receivable program agreement contains a cross-default provision that is triggered if IPL or Alliant Energy incurs an event of default on debt totaling $100 million or more. If an event of default under IPL’s sales of accounts receivable program agreement occurs, then the counterparty could terminate such agreement. Refer to Note 5(b) for additional information regarding IPL’s sales of accounts receivable program. Guarantees and Indemnifications - At December 31, 2025, various guarantees and indemnifications are outstanding related to Alliant Energy’s cash equity ownership interest in a non-utility wind farm, prior divestiture activities, transfers of renewable tax credits to other corporate taxpayers and electric transmission infrastructure. Refer to Note 1 6 (d) for additional information. Certain Financial Commitments - Contractual Obligations - Alliant Energy, IPL and WPL have various long-term contractual obligations as of December 31, 2025, which include long-term debt maturities in Note 8 (b) , operating and finance leases in Note 9 , capital purchase obligations in Note 1 6 (a) , and other purchase obligations in Note 1 6 (b) . At December 31, 2025, Alliant Energy, IPL and WPL had no uncertain tax positions recorded as liabilities. Refer to Note 1 2 (a) for anticipated pension and OPEB funding amounts. Refer to “ Construction and Acquisition Expenditures ” above for additional information on construction and acquisition programs. In addition, at December 31, 2025, there were various other liabilities included on the balance sheets that, due to the nature of the liabilities, the timing of payments cannot be estimated. OTHER MATTERS Market Risk Sensitive Instruments and Positions - Primary market risk exposures are associated with commodity prices, counterparty credit risk, investment prices and interest rates. Risk management policies are used to monitor and assist in mitigating these market risks and derivative instruments are used to manage some of the exposures related to commodity prices and interest rates. Refer to Notes 1(h) and 1 4 for further discussion of derivative instruments, and Note 1(g) for details of utility cost recovery mechanisms that significantly reduce commodity risk. Commodity Price - Alliant Energy, IPL and WPL are exposed to the impact of market fluctuations in the price and transportation costs of commodities they procure and market. Established policies and procedures mitigate risks associated with these market fluctuations, including the use of various commodity derivatives and contracts of various durations for the forward sale and purchase of these commodities. Exposure to commodity price risks in the utility businesses is also significantly mitigated by current rate-making structures in place for recovery of fuel-related costs as well as the cost of natural gas purchased for resale. IPL’s electric and gas tariffs and WPL’s wholesale electric and gas tariffs provide for subsequent monthly adjustments to their tariff rates for material changes in prudently incurred commodity costs. IPL’s and WPL’s rate mechanisms, combined with commodity derivatives, significantly reduce commodity risk associated with their electric and gas service. WPL’s retail electric service is exposed to the impact of changes in commodity prices due largely to the current retail recovery mechanism in place in Wisconsin for fuel-related costs. Counterparty Credit Risk - Alliant Energy, IPL, and WPL are exposed to credit risk related to losses resulting from counterparties’ nonperformance of their contractual obligations. Alliant Energy, IPL and WPL maintain credit policies intended to minimize overall credit risk and actively monitor these policies to reflect changes and scope of operations. Alliant Energy, IPL, and WPL conduct credit reviews for certain counterparties, and employ credit risk controls such as letters of credit, surety bonds, parental guarantees, master netting agreements and termination provisions. Credit exposure is monitored, and when necessary, activity with a specific counterparty is limited until credit enhancement is provided. Distress in the financial markets could increase Alliant Energy’s, IPL’s and WPL’s credit risk. Investment Price - Alliant Energy, IPL and WPL are exposed to investment price risk as a result of their investments in securities, largely related to securities held by their pension and OPEB plans, as well as unconsolidated investments accounted for under the equity method of accounting. Refer to Note 1 2 (a) for details of the securities held by their pension and OPEB plans, and Note 6 for details of equity investments. Refer to “ Critical Accounting Estimates ” for the impact on retirement plan costs of changes in the rate of returns earned by plan assets. 45 Table of Contents Interest Rate - Alliant Energy, IPL and WPL are exposed to risk resulting from changes in interest rates associated with variable-rate borrowings. In addition, Alliant Energy and IPL are exposed to risk resulting from changes in interest rates on cash amounts outstanding under IPL’s sales of accounts receivable program. Assuming the impact of a hypothetical 100 basis point increase in interest rates on variable-rate borrowings and cash amounts outstanding under IPL’s sales of accounts receivable program at December 31, 2025, Alliant Energy’s, IPL’s and WPL’s annual pre-tax expense would increase by approximately $2 million, $2 million and $0 million, respectively. Refer to Notes 5(b) and 8 for additional information on cash amounts outstanding under IPL’s sales of accounts receivable program, and short- and long-term variable-rate borrowings, respectively. Refer to “ Critical Accounting Estimates ” for the impacts of changes in discount rates on retirement plan obligations and costs. Critical Accounting Estimates - Alliant Energy’s, IPL’s and WPL’s financial statements are prepared in conformity with GAAP, which requires management to apply accounting policies, judgments and assumptions, and make estimates that affect results of operations and the amounts of assets and liabilities reported in the financial statements. The following accounting estimates are critical to the business and the understanding of financial results as they require critical assumptions and judgments by management. The results of these assumptions and judgments form the basis for making estimates regarding the results of operations and the amounts of assets and liabilities that are not readily apparent from other sources. Actual financial results may differ materially from estimates. Management has discussed these critical accounting estimates with the Audit Committee of the Board of Directors. Refer to Note 1 for additional discussion of accounting estimates used in the preparation of the financial statements. Regulatory Assets and Regulatory Liabilities - IPL and WPL are regulated by various federal and state regulatory agencies. As a result, they are subject to GAAP for regulated operations, which recognizes that the actions of a regulator can provide reasonable assurance of the existence of an asset or liability. Regulatory assets or regulatory liabilities arise as a result of a difference between GAAP and actions imposed by the regulatory agencies in the rate-making process. Regulatory assets generally represent incurred costs that have been deferred as such costs are probable of recovery in future customer rates. Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the related costs have not yet been incurred. Regulatory assets and regulatory liabilities are recognized in accordance with the rulings of applicable federal and state regulators, and future regulatory rulings may impact the carrying value and accounting treatment of regulatory assets and regulatory liabilities. Note 2 provides details of the nature and amounts of regulatory assets and regulatory liabilities assessed at December 31, 2025. Assumptions and judgments are made each reporting period regarding whether regulatory assets are probable of future recovery and regulatory liabilities are probable future obligations by considering factors such as regulatory environment changes, rate orders issued by the applicable regulatory agencies, historical decisions by such regulatory agencies regarding similar regulatory assets and regulatory liabilities, and subsequent events of such regulatory agencies. The decisions made by regulatory agencies have an impact on the recovery of costs, the rate of return on invested capital and the timing and amount of assets to be recovered by rates. A change in these decisions may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Income Taxes - Alliant Energy, IPL and WPL are subject to income taxes in various jurisdictions. Assumptions and judgments are made each reporting period to estimate income tax assets, liabilities, benefits and expenses. Judgments and assumptions are supported by historical data and reasonable projections. Significant changes in these judgments and assumptions could have a material impact on financial condition and results of operations. Alliant Energy’s and IPL’s critical assumptions and judgments for 2025 included estimates of qualifying deductions for repairs expenditures, allocation of mixed service costs and state depreciation, and costs related to retirement or removal of depreciable property due to the impact of Iowa rate-making principles on such property-related differences. Critical assumptions and judgments also include projections of future taxable income used to determine the ability to utilize federal credit carryforwards prior to their expiration. Refer to Note 1 1 for further discussion of tax matters. Effect of Rate-making on Property-related Differences - Alliant Energy’s and IPL’s effective income tax rates are normally impacted by certain property-related differences at IPL for which deferred tax is not recorded in the income statement pursuant to Iowa rate-making principles. Changes in methods or assumptions regarding the amount of IPL’s qualifying repairs expenditures, allocation of mixed service costs and state depreciation, and costs related to retirement or removal of depreciable property, could result in a material impact on Alliant Energy’s and IPL’s financial condition and results of operations. Carryforward Utilization - Significant federal tax credit carryforwards exist for Alliant Energy, IPL and WPL as of December 31, 2025. Based on projections of current and future taxable income, Alliant Energy, IPL and WPL plan to utilize all of these carryforwards more than five years before expiration. Changes in tax regulations or assumptions regarding current and future taxable income could require valuation allowances in the future resulting in a material impact on financial condition and results of operations. 46 Table of Contents Long-Lived Assets - Periodic assessments regarding the recoverability of certain long-lived assets are completed when factors indicate the carrying value of such assets may not be recoverable or such assets are planned to be sold. These assessments require significant assumptions and judgments by management. The long-lived assets assessed for impairment generally include certain assets within regulated operations that may not be fully recovered from IPL’s and WPL’s customers as a result of regulatory decisions in the future, and assets within non-utility operations that are proposed to be sold or are currently generating operating losses. Regulated Operations - Long-lived assets within regulated operations are reviewed for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL or WPL is disallowed recovery of any portion of the carrying value of its regulated property, plant and equipment that has been recently completed or is probable of being retired early, an impairment charge is recognized equal to the amount of the carrying value that was disallowed recovery. If IPL or WPL is disallowed a full or partial return on the carrying value of its regulated property, plant and equipment that has been recently completed or is probable of being retired early, an impairment charge is recognized equal to the difference between the carrying amount of the asset and the present value of the future revenues expected from its regulated property, plant and equipment. Refer to Note 3 for further discussion of Alliant Energy’s, IPL and WPL’s long-lived assets within their regulated operations. AROs - The fair value of a legal obligation associated with the retirement of an asset is recorded as a liability when an asset is placed in service, when a legal obligation is subsequently identified or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement costs. Alliant Energy, IPL and WPL estimate the fair value of their AROs using present value techniques, in which they make various assumptions, including estimates of the amounts and timing of future cash flows associated with retirement activities, inflation and discount rates. Estimates of the timing and amounts of future cash outlays are based on projections of when and how assets will be retired and the cost of future removal activities. These amounts are expected to be adjusted in the future, as additional information is obtained for the specific site closure plans, including the determination of whether or not individual sites are considered legal obligations and the acceptance and approval of compliance approaches, which could change management assumptions and result in a material change to the recorded ARO amounts. Future updates, including updates due to the enactment of the revised CCR Rule, could have a material impact on Alliant Energy’s, IPL’s and WPL’s financial condition and results of operations. Refer to Note 1 3 for further discussion of AROs. Pensions and Other Postretirement Benefits - Alliant Energy, IPL and WPL sponsor various defined benefit pension and OPEB plans that provide benefits to a significant portion of their employees and retirees. Assumptions and judgments are made periodically to estimate the obligations and costs related to their retirement plans. There are many judgments and assumptions involved in determining an entity’s pension and other postretirement liabilities and costs each period including employee demographics (including life expectancies and compensation levels), discount rates, assumed rates of return and funding. Changes made to plan provisions may also impact current and future benefits costs. Judgments and assumptions are supported by historical data and reasonable projections and are reviewed at least annually. The following table shows the impacts of changing certain key actuarial assumptions discussed above (in millions): Defined Benefit Pension Plans OPEB Plans Change in Actuarial Assumption Impact on Projected Benefit Obligation at December 31, 2025 Impact on 2026 Net Periodic Benefit Costs Impact on Accumulated Benefit Obligation at December 31, 2025 Impact on 2026 Net Periodic Benefit Costs Alliant Energy 1% change in discount rate $83 $7 $10 $— 1% change in expected rate of return N/A 7 N/A 1 IPL 1% change in discount rate 39 3 4 — 1% change in expected rate of return N/A 3 N/A 1 WPL 1% change in discount rate 37 3 4 — 1% change in expected rate of return N/A 3 N/A — Contingencies - Assumptions and judgments are made each reporting period regarding the future outcome of contingent events. Loss contingency amounts are recorded for any contingent events for which the likelihood of loss is probable and able to be reasonably estimated based upon current available information. The amounts recorded may differ from actuals when the uncertainty is resolved. The estimates made in accounting for contingencies, and the gains and losses that are recorded upon the ultimate resolution of these uncertainties, could have a significant effect on results of operations and the amount of assets and liabilities in the financial statements. Certain contingencies require estimation each reporting period of the expected credit losses on those contingencies, which requires significant judgment and may result in the recognition of a credit loss liability. Note 1 6 provides further discussion of contingencies assessed at December 31, 2025 that may have a material impact on financial condition and results of operations, including various pending legal proceedings, guarantees and indemnifications. 47 Table of Contents Retroactive Tariffs on Solar Cells and Modules - In August 2023, the U.S. Department of Commerce (DOC) issued a final ruling that found solar cells and modules produced in certain Southeast Asian countries, including Cambodia, Malaysia, Thailand and Vietnam, using parts and components produced in China, were circumventing pre-existing antidumping and countervailing duties on China. Consistent with a June 2022 Presidential Proclamation, the DOC issued rules granting duty-free treatment of solar cells and modules imported from these four countries as of June 2022 until June 2024. In August 2025, the U.S. Court of International Trade (CIT) ruled that this two-year duty suspension, as issued, was impermissible. In September 2025, this ruling from the CIT was appealed to the Federal Circuit. The CIT's order has been stayed pending appeal. Alliant Energy, IPL and WPL continue to assess the potential impact of these tariffs on previously completed solar generation projects and are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing litigation. ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK Quantitative and Qualitative Disclosures About Market Risk are reported in “ Other Matters - Market Risk Sensitive Instruments and Positions ” in MDA. ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA 48 Table of Contents REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM To the Shareowners and the Board of Directors of Alliant Energy Corporation: Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, 2025 and 2024, the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, 2025, and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.