What changed in this filing

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Item 1. Business

2026-02-20 compared with 2025-02-21 · 51 added, 70 removed, 401 unchanged (23% of the section changed)

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The primary first tier wholly-owned subsidiaries of Alliant Energy are as follows:

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1) IPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Iowa.

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At December 31, 2025, IPL supplied electric and natural gas service to approximately 505,000 and 230,000 retail customers, respectively, in Iowa.

IPL also sells electricity to wholesale customers in Minnesota (IPL’s related wholesale power agreement expires July 2025), Illinois and Iowa.

IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa, which are each under contract through 2025 for taking minimum quantities of annual steam usage, with certain conditions, after which IPL expects to exit the steam business.

IPL also sells electricity to wholesale customers in Illinois and Iowa and was engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa, which 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.

2) WPL - is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas to retail customers in select markets in Wisconsin.

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ATC is an independent, for-profit, transmission-only company.

ATC Holdco LLC holds an interest in Duke-American Transmission Company, LLC, a joint venture between Duke Energy Corporation and ATC, that owns electric transmission infrastructure in North America.

ATC Holdco LLC holds an interest in Duke-American Transmission Company, LLC, which holds a note receivable related to the previously owned electric transmission infrastructure in North America.

Corporate Venture Investments - includes various minority ownership interests in regional and national venture funds, including a global coalition of energy companies working together to help identify and research innovative technologies and business models within the emerging energy economy.

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freight brokerage services;

wind turbine blade recycling services;

and a rail-served warehouse in Iowa.

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All of WPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 965 collective bargaining agreement, which expires May 31, 2026.

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Safety - Safety is integral to our company’s culture.

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Total Rewards - Our market-competitive Total Rewards programs are designed to meet the varied and evolving needs of our employees.

Through a variety of health, welfare and compensation programs, we offer employees choice and control, and help support their financial, physical, and mental well-being.

We provide tools and resources to employees to help maintain and improve their health.

Short- and long-term incentive plans have a mix of operational and financial metrics that align employees with strategic corporate goals.

Through a variety of programs, we offer employees choice and control, and help support their financial, physical, and mental well-being.

We also provide a personal family advocate to help employees navigate their healthcare needs as well as other resources to help maintain and improve their health.

In addition to competitive salaries and wages, our Total Rewards programs include:

• competitive short- and long-term incentive compensation;

• competitive short- and long-term incentive compensation that align employees with strategic corporate goals;

• a 401(k) savings plan with an employer contribution and employer match;

• healthcare and insurance benefits, including medical, vision, dental, life, short-term disability, and long-term disability insurance;

• healthcare and insurance benefits, including medical, vision, dental, mental health resources, life, short-term disability, and long-term disability insurance;

• health savings and flexible spending accounts;

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Our efforts to advance employee engagement in our workforce include:

We offer various learning opportunities for employees, such as participating in area summits, supporting company-wide listening sessions, providing training opportunities, and hosting speakers, among other programs, as well as leaders facilitating conversations around employee engagement, helping to ensure employees are seen, heard and valued;

We offer various learning opportunities for employees, such as participating in area summits, supporting and engaging with company-wide Communities of Purpose, providing training opportunities, and hosting speakers where employees can ask questions and interact with business leaders and other experts, among other programs, as well as leaders facilitating conversations around employee engagement, helping to ensure employees are seen, heard and valued;

• Listening and responding:

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Our Leadership Team identifies and champions initiatives to help advance a culture that values employee engagement.

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Talent Development and Workforce Readiness - We support all employees in their skill development and career growth, offering several training opportunities, development programs and tuition reimbursement, as well as leadership development and succession planning.

Development goals and conversations with leadership help identify opportunities to learn through a mix of on-the-job experience, collaboration and formal content to build needed skills for today and the future.

To help attract and introduce a wide range of candidates to our industry, we have early careers programs that include apprenticeships, youth programs (high school) and internships (college).

To help attract and introduce a wide range of candidates to our industry, we have early careers programs that include youth programs (high school), pre-apprenticeships, and apprenticeships.

Our programs provide a pipeline of talented students to engage in meaningful, hands-on work experiences.

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FERC designated North American Electric Reliability Corporation, which also provides oversight of cybersecurity standards, as the overarching Electric Reliability Organization.

Midwest Reliability Organization, which is a regional member of North American Electric Reliability Corporation, has direct responsibility for mandatory electric reliability standards for IPL and WPL.

The Midwest Reliability Organization, which is a regional member of North American Electric Reliability Corporation, has direct responsibility for mandatory electric reliability standards for IPL and WPL.

Federal Power Act of 1935 - FERC also has jurisdiction, under the Federal Power Act of 1935, over certain electric utility facilities and operations, electric wholesale sales, interstate electric transmission rates, dividend payments, issuance of IPL’s securities, and accounting practices of Corporate Services, IPL and WPL.

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In Iowa, counties and cities are prohibited from regulating the sale of natural gas and propane, which supports IPL’s ability to provide gas utility service to retail customers and industries.

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Retail Utility Base Rates - IPL files periodic requests with the IUC for retail rate changes and may base those requests on either historical or forward-looking test periods.

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Also, IPL is required to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels.

IPL would apply excess earnings to the remaining net book value of IPL’s highest earning asset with advance ratemaking principles based on its authorized return on common equity.

Refer to “ Rate Matters ” in MDA for discussion of IPL’s retail electric base rate moratorium from October 2025 through September 2029 approved by the IUC in IPL’s most recent retail electric rate review.

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At the end of the program, any accumulated deficit balance would be addressed in IPL’s next rate review, and any accumulated surplus balance would not result in any return to IPL.

Electric Generating Unit Environmental Controls Projects - At its sole discretion, IPL may submit an updated emissions plan and budget to the IUC setting out a multi-year plan and budget for managing regulated emissions from its coal-fired EGUs in a cost-effective manner.

IPL must simultaneously submit this plan and budget to the Iowa Department of Natural Resources for a determination of whether the plan and budget meet state environmental requirements for regulated emissions.

The reasonable and prudent costs associated with implementing the approved plan are expected to be included in IPL’s future retail electric rates.

PSCW - WPL is subject to regulation by the PSCW related to its operations in Wisconsin for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, issuance and use of proceeds of securities, affiliate transactions, approval of the location and construction of EGUs and certain other additions and extensions to facilities.

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Currently, WPL is required to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels.

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Public Benefits - WPL contributes 1.2% of its annual retail utility revenues to help fund Focus on Energy, Wisconsin’s state-wide energy efficiency and renewable energy resource program.

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Refer to Note 1(g) for discussion of the recovery of these costs from WPL’s retail electric and gas customers.

New Electric Generating Units - A CA application is required to be filed with the PSCW for construction approval of any new EGU (including energy storage) with a capacity of less than 100 MW and a project cost of $16.3 million or more.

WPL must obtain a CPCN from the PSCW in order to construct a new EGU (including energy storage) in Wisconsin with a capacity of 100 MW or more.

New Electric Generating Units - A CA application is required to be filed with the PSCW for construction approval of any new EGU or energy storage with a capacity of less than 100 MW and a project cost of $16.3 million or more.

WPL must obtain a CPCN from the PSCW in order to construct a new EGU or energy storage in Wisconsin with a capacity of 100 MW or more.

In addition, WPL’s ownership and operation of EGUs (including those located outside the state of Wisconsin) to serve Wisconsin customers are subject to retail utility rate regulation by the PSCW.

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WPL can proceed with an approved project under traditional rate-making terms or accept authorized rate-making principles under Wisconsin law.

Department of Homeland Security Transportation Security Administration - Alliant Energy, IPL and WPL are subject to regulation for physical and cybersecurity of their natural gas pipeline systems, and are applying, and monitoring for changes to, these requirements to their pipeline systems.

Department of Homeland Security Transportation Security Administration - Alliant Energy, IPL and WPL are subject to regulation for physical and cybersecurity of their natural gas pipeline systems.

Environmental - Alliant Energy, IPL and WPL are subject to regulation of environmental matters by federal, state and local authorities as a result of their current and past operations.

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Climate Change and Greenhouse Gas Regulations - In 2007, the Supreme Court provided direction on the EPA’s authority to regulate GHG and ruled that these emissions are covered by the CAA.

In 2009, the EPA issued a ruling that found GHG emissions contribute to climate change and therefore threaten public health and welfare, which is the basis for implementing CO2 reduction standards under the CAA.

In 2009, the EPA issued a ruling that found GHG emissions from motor vehicles contribute to climate change and therefore threaten public health and welfare, which is the basis for implementing CO2 reduction standards under the CAA.

The primary GHG directly emitted from Alliant Energy’s utility operations is CO2 from the combustion of fossil fuels at its EGUs.

Clean Air Act Section 111(d) - In May 2024, the EPA enacted the final Section 111(d) rule under the CAA for certain fossil-fueled EGUs, which requires states to implement plans to reduce CO2 emissions through various Best System of Emission Reduction (BSER) measures at affected sources, including retirement, enforceable limits on operational capacity, co-firing with low-GHG fuels, or carbon capture and energy storage technology.

State plans are subject to EPA approval, and must be submitted by May 2026.

The final rule’s compliance requirements will be phased in beginning in 2030 and covers fossil-fueled EGUs that utilize steam boilers to generate electricity, including IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, Prairie Creek Generating Station Unit 3 and Louisa Generating Station, WPL’s coal-fired Edgewater Generating Station Unit 5 (WPL currently plans to convert Edgewater Unit 5 to natural gas in 2028, subject to regulatory approvals), and IPL’s natural gas-fired Burlington Generating Station and Prairie Creek Generating Station Unit 4.

In February 2026, the EPA finalized a rule to rescind its 2009 finding that GHG contributes to climate change, concluding that regulation of GHG falls outside of the scope of the CAA.

Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing or potential litigation.

Cl ean Air Act Section 111(d) - In May 2024, the EPA enacted the final Section 111(d) rule under the CAA for certain fossil-fueled EGUs, which requires states to implement plans to reduce CO2 emissions through various Best System of Emission Reduction (BSER) measures at affected sources, including retirement, enforceable limits on operational capacity, co-firing with low-GHG fuels, or carbon capture and storage technology.

The final rule does not apply to EGUs that are retired by January 2032.

If WPL’s coal-fired Columbia Energy Center is retired by the end of 2029, the final rule would not be applicable;

however, if WPL converts Columbia Unit 1 and/or Unit 2 to natural gas, then the final rule would be applicable for the EGUs that are converted.

In addition, the final rule does not impact existing natural gas-fired combustion turbines, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center;

however, these EGUs could be subject to future Section 111(d) rules to reduce CO2 emissions from existing combustion turbines.

Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing litigation.

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In addition, the final rule does not impact existing natural gas-fired combustion turbines.

The final rule’s compliance requirements will be phased in beginning in 2030 and covers fossil-fueled EGUs that utilize steam boilers to generate electricity, including IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, and Louisa Generating Station, WPL’s coal-fired Edgewater Generating Station Unit 5 and Columbia Units 1 and 2, and IPL’s natural gas-fired Burlington Generating Station and Prairie Creek Generating Station Units 3 and 4.

In June 2025, the EPA proposed to repeal CAA Section 111(d) and a final rule is expected in the first half of 2026.

The proposed repeal has delayed the submittal of state plans for EPA approval by the May 2026 deadline.

Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, including resolution of ongoing or potential litigation.

Clean Air Act Section 111(b) - In 2015, the EPA published final standards under Section 111(b) of the CAA, which establish CO2 emissions limits for certain new fossil-fueled EGUs, including IPL’s Marshalltown Generation Station and WPL’s West Riverside Energy Center.

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The final revised standards do not apply to IPL’s and WPL’s current fossil-fueled EGU combustion turbines since they were all placed into service before May 23, 2023 and have not been reconstructed since that date.

Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these revised standards, including resolution of ongoing litigation.

In June 2025, the EPA proposed to repeal the May 2024 111(b) revised standards and a final rule is expected in the first half of 2026.

Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these revised standards, including resolution of ongoing or potential litigation.

Cross-State Air Pollution Rule - CSAPR is a regional sulfur dioxide and nitrogen oxides cap-and-trade program, where compliance with emission limits may be achieved by purchasing emission allowances and/or reducing emissions through changes in operations or the additions of environmental controls.

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CSAPR establishes state-specific annual sulfur dioxide and nitrogen oxides emission caps and ozone season nitrogen oxides emission caps.

In 2023, the EPA finalized revisions to the CSAPR state-specific ozone season nitrogen oxides emission caps and utility-specific emission allowances for certain states, including Wisconsin, beginning in 2023;

however, these revisions were stayed by the Supreme Court in June 2024.

In November 2024, the EPA issued an interim final rule to stay the 2023 rule and re-establish the prior emission caps and allowance allocations, including Wisconsin, pending judicial review.

WPL currently receives, and expects to receive in the future, enough CSAPR emission allowances to ensure ongoing compliance without the need to purchase additional allowances or materially curtail operations.

These revisions do not currently apply to Iowa;

however, Iowa could be included in a future rule.

As a result, Alliant Energy and IPL are currently unable to predict with certainty the future outcome or impacts of these matters.

IPL and WPL currently receive, and expects to receive in the future, enough CSAPR emission allowances to ensure ongoing compliance without the need to purchase additional allowances or materially curtail operations.

New Source Performance Standards (NSPS) for Combustion Turbines - The EPA establishes requirements under the CAA for various categories of stationary sources that cause or contribute significantly to air pollution, and may reasonably be anticipated to endanger public health or welfare, which are referred to as NSPS.

These standards reflect the degree of emission limitation achievable through the application of the BSER.

In December 2024, the EPA proposed updates to the NSPS for combustion turbines built, reconstructed, or modified after December 13, 2024, which would establish more stringent emission limits for nitrogen oxides emissions and retain the current sulfur dioxide emission limits.

This proposal would establish size-based subcategories for new, reconstructed or modified combustion turbines, and could require combustion controls or selective catalytic reduction control equipment.

Alliant Energy, IPL and WPL are currently evaluating the proposed rule and are unable to predict with certainty future compliance impacts;

however, costs to comply with this rule could have a material impact on their financial condition and results of operations.

In January 2026, EPA finalized updates to the NSPS for combustion turbines built, reconstructed, or modified after December 13, 2024.

The rule established revised nitrogen oxides emission limits based on the size, capacity factor, efficiency, and fuel type for new, reconstructed or modified combustion turbines.

The rule maintained the prior sulfur dioxide emission limits.

Alliant Energy, IPL and WPL expect to be able to comply with the updated NSPS requirements and will continue to monitor potential litigation.

Water Quality -

Effluent Limitation Guidelines - In May 2024, the EPA enacted a final rule that revises discharge limits for specific categories of wastewater from existing steam EGUs.

The new limitations will be implemented in each facility’s wastewater discharge permits issued by state agencies and become effective as soon as possible but no later than December 31, 2029.

The new limitations will be implemented in each facility’s wastewater discharge permits issued by state agencies.

In December 2025, EPA finalized an extended timeframe for the new requirements, which must now be implemented no later than December 31, 2034.

Alliant Energy, IPL and WPL are currently evaluating the final rule and are unable to predict with certainty future compliance impacts, including resolution of ongoing litigation;

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IPL and WPL have coal ash ponds at current and former EGU sites, and active and inactive CCR landfills, that are impacted by this rule.

In February 2026, the EPA issued a final rule extending certain compliance deadlines under the CCR Rule.

Alliant Energy, IPL and WPL continue to evaluate the revised CCR Rule and are unable to predict with certainty the future outcome or impact of these updates, including resolution of ongoing litigation.

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IPL and WPL currently exceed their respective renewable energy standards requirements.

3) STRATEGY - Refer to “ Overview ” in MDA for discussion of Alliant Energy’s strategy, which supports its mission to deliver energy solutions and exceptional service that its customers and communities count on - affordably, safely, reliably and sustainably.

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INFORMATION RELATING TO UTILITY OPERATIONS

Alliant Energy’s utility business includes the operations of IPL (electric, gas and steam operations) and WPL (electric and gas operations), which are both reportable segments.

Alliant Energy’s utility business (electric and gas) includes the operations of IPL and WPL, which are both reportable segments.

IPL’s and WPL’s electric, gas and other revenues as a percentage of total revenues were as follows:

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General - Alliant Energy’s electric utility operations are located in the Midwest with IPL providing retail and wholesale electric service in Iowa and WPL providing retail and wholesale electric service in Wisconsin.

IPL also sells electricity to wholesale customers in Minnesota and Illinois.

IPL also sells electricity to wholesale customers in Illinois.

IPL’s wholesale power agreement with Southern Minnesota Energy Cooperative expired in 2025.

Refer to the “ Electric Operating Information ” tables for additional details regarding electric utility operations.

Customers - IPL and WPL provide electric utility service to a large base of retail customers in several industries, with the largest concentrations in the farming, agriculture, industrial manufacturing, chemical (including ethanol), packaging and food industries.

IPL and WPL also sell electricity to wholesale customers, which primarily consist of municipalities and rural electric cooperatives.

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Electric sales are also impacted to a certain extent in the winter months due to heating requirements.

Competition - Retail electric customers in Iowa and Wisconsin currently do not have the ability to choose their electric supplier, and IPL and WPL have obligations to serve all their retail electric customers.

Although electric service in Iowa and Wisconsin is regulated, IPL and WPL still face competition from self-generation by large industrial customers, customer- and third party-owned generation (e.g.

Competition - Retail electric customers in Iowa and Wisconsin currently do not have the ability to choose their electric supplier, and IPL and WPL have obligations to serve all retail electric customers in their service territories.

Although electric service in Iowa and Wisconsin is regulated, IPL and WPL face competition from self-generation by large industrial customers, customer- and third party-owned generation (e.g.

solar panels), alternative energy sources, and petitions to municipalize (Iowa) as well as service territory expansions by municipal utilities through annexations (Wisconsin).

In addition, the wholesale power market is competitive and IPL and WPL compete against independent power producers, other utilities and MISO market purchases to serve wholesale customers for their electric energy and capacity needs.

Alliant Energy’s strategy includes actions to retain current customers and attract new customers into IPL’s and WPL’s service territories in an effort to keep energy rates low for all of their customers.

Refer to “ Overview ” in MDA for discussion of the strategy element focusing on growing customer demand.

Electric Supply - Alliant Energy, IPL and WPL have met, and expect to continue meeting, customer demand of electricity through a mix of electric supply, including owned EGUs, PPAs and additional purchases from wholesale energy markets.

Alliant Energy expects its current mix of electric supply to continue to evolve with new wind and solar generation, energy storage facilities, new natural gas resources, refurbishing of existing wind farms, improvements at existing natural gas-fired EGUs and converting certain coal-fired EGUs to natural gas.

Electric Supply - Alliant Energy, IPL and WPL have met, and expect to continue meeting, customer demand for electricity through a mix of electric supply, including owned EGUs, PPAs and additional purchases from wholesale energy markets.

Alliant Energy expects its current mix of electric supply to continue to evolve with new renewable generation, energy storage facilities, new natural gas resources, refurbishing of existing wind farms, improvements at existing natural gas-fired EGUs and converting certain coal-fired EGUs to natural gas.

Long-term generation plans are intended to meet growing customer demand, reduce air emissions and water impacts, reduce reliance on wholesale market purchases and mitigate the impacts of future EGU retirements while maintaining compliance with long-term electric demand planning reserve margins, renewable energy standards established by regulators, among other requirements.

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IPL and WPL utilize accredited capacity from EGUs they own, and have rights to through PPAs, to meet a substantial portion of their current MISO planning reserve margin requirements and periodically rely on short-term market capacity purchases to supplement the accredited capacity from such EGUs.

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MISO Seasonal Resource Adequacy Process - MISO’s resource adequacy process includes capacity planning reserve margins and capacity accreditation requirements with four distinct seasons, to help ensure the reliability of electricity in the MISO region.

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Alliant Energy, IPL and WPL believe they are reasonably insulated against gas price volatility for these EGUs given their use of forward contracts and hedging practices, as well as their regulatory cost-recovery mechanisms.

Coal - Coal is one of the fuel sources for owned EGUs.

Coal contracts entered into with different entities help ensure that a specified supply of coal is available, and delivered, at known prices for IPL’s and WPL’s coal-fired EGUs.

Coal - Coal contracts entered into with different entities help ensure that a specified supply of coal is available, and delivered, at known prices for IPL’s and WPL’s coal-fired EGUs.

Alliant Energy, IPL and WPL believe their coal supply portfolio represents a reasonable balance between the risks of insufficient supplies and those associated with being unable to respond to future coal market changes.

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Purchased Power - IPL and WPL periodically enter into PPAs and purchase electricity from wholesale energy markets to meet a portion of their customer demand for electricity.

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Electric Transmission - IPL and WPL do not own electric transmission service assets and currently receive transmission services from ITC and ATC, respectively.

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If the rates proposed by ITC or ATC are determined by FERC to be unjust or unreasonable, or another mechanism is determined by FERC to be just and reasonable, ITC’s or ATC’s rates would change accordingly.

Refer to Note 1(g) for discussion of a transmission cost rider utilized by IPL for recovery of its electric transmission service expense, and discussion of WPL’s escrow for recovery of electric transmission service expense, which is recovered from its retail electric customers through changes in base rates determined during periodic rate proceedings.

Refer to Note 1 6 (g) for discussion of a court case and resulting FERC order, which decreased the base return on equity authorized for MISO transmission owners, including ATC.

Refer to N ote 1(g) for discussion of a transmission cost rider utilized by IPL for recovery of its electric transmission service expense, and discussion of WPL’s escrow for recovery of electric transmission service expense, which is recovered from its retail electric customers through changes in base rates determined during periodic rate proceedings.

MISO Markets - IPL and WPL are members of MISO, a FERC-approved Regional Transmission Organization, which is responsible for monitoring and ensuring equal access to the transmission system in their footprint.

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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 Margin ” above for discussion of MISO’s seasonal resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements.

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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.

Electric Operating Information - Alliant Energy 2025 2024 2023

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Cedar Rapids, Iowa (IPL) (normal - 831)

1,054 890 974

Madison, Wisconsin (WPL) (normal - 716)

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(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.

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Electric Operating Information IPL WPL

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2) GAS UTILITY OPERATIONS

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Refer to the “ Gas Operating Information ” tables for additional details regarding gas utility operations.

Refer to Note 1(g) for information relating to utility natural gas cost recovery mechanisms and Note 1 6 (b) for discussion of natural gas commitments.

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).

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Purchased gas costs per Dth sold to retail customers $5.24 $5.06 $6.37

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Gas Operating Information IPL WPL

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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 provides steam for IPL’s two high-pressure steam customers in Iowa.

These customers are each under contract through 2025 for taking minimum quantities of annual steam usage, with certain conditions, after which IPL currently expects to exit the steam business.

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.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1. Business