ALLIANT ENERGY CORP (LNT) FY 2022 MD&A

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, as well as 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 2022 compared to 2021. Refer to MDA in the combined 2021 Form 10-K for details on certain financial information for 2021 compared to 2020.

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OVERVIEW

Mission, Purpose and Strategy

Alliant Energy’s mission is to deliver affordable energy solutions and exceptional service that its customers and communities count on - affordably, safely, reliably, and sustainably. This mission aligns with Alliant Energy’s purpose - to serve customers and build stronger communities - which guides it through the ever-changing dynamics of the economy and the energy industry. Alliant Energy takes its responsibility as a corporate citizen seriously and remains a careful steward of the environment and supports the communities in its service territories. Alliant Energy’s mission and purpose is supported by a strategy focused on meeting the evolving expectations of customers while providing an attractive return for investors, and pursuing emerging technologies and safe, sustainable methods of energy production. This strategy includes the following key elements:

Providing affordable energy solutions to customers - Alliant Energy’s strategy focuses on affordable energy solutions that support retention and growth of its existing customers and attract new customers to its service territories.

Key Highlights -

•Alliant Energy’s Clean Energy Blueprint, also known as its cleaner energy strategy, continues to add clean energy resources in Iowa and Wisconsin, which directly reinvests in the communities Alliant Energy serves through the addition of skilled jobs, economic development and increased tax revenue. The execution of Alliant Energy’s strategy is expected to result in cost benefits for its utility customers by continuing to add renewable energy projects that generate fuel cost benefits and renewable tax credits that are provided to its electric customers. Alliant Energy, IPL and WPL currently expect to utilize various provisions of the Inflation Reduction Act of 2022 to enhance the tax benefits expected from their announced solar and battery storage projects, including transferring certain future tax credits from such projects to other corporate taxpayers.

•In 2022, Alliant Energy’s wind generation was the highest in its history, which resulted in renewable tax credits and fuel cost savings for its customers.

•Reductions in Iowa corporate income tax rates resulting from tax reform enacted in March 2022 are expected to provide cost benefits to IPL’s customers in the future.

•IPL maintaining flat base rates for its retail electric and gas customers in 2021 and 2022.

•IPL’s renewable energy rider became effective February 26, 2020, which allows for annual adjustments to electric rates charged to IPL’s retail electric customers for actual renewable energy costs incurred to fund IPL’s 1,000 MW of wind EGUs placed in service in 2019 and 2020, and related tax benefits, including production tax credits, that are provided to its electric customers.

•Providing $35 million of billing credits to IPL’s retail electric customers beginning in the third quarter of 2020 through June 2021, largely driven by Federal Tax Reform benefits for customers.

•Significant fuel cost reductions achieved in 2021 and 2022 as a result of shortening the term of IPL’s DAEC PPA by 5 years.

•Issuance of new long-term debt at historically low interest rates for IPL ($300 million of 3.1% senior debentures due 2051) and WPL ($300 million of 1.95% green bonds due 2031) in 2021, and WPL ($600 million of 3.95% green bonds due 2032) in 2022.

•Redemption of IPL’s 5.1% cumulative preferred stock in 2021.

•Levelized cost recovery mechanism for the remaining net book value of Edgewater Unit 5, which helps reduce customer costs in 2022 and 2023.

Making customer-focused investments - Alliant Energy’s strategic priorities include making significant customer-focused investments toward cleaner energy and resilient and sustainable customer solutions. Alliant Energy’s strategy drives a capital allocation process focused on: 1) transitioning its generation portfolio to meet the growing interest of customers for reliable and sustainable sources of energy, 2) upgrading its electric and gas distribution systems to strengthen safety and resiliency, as well as enable distributed energy solutions in its service territories, and 3) enhancing its customers’ and employees’ experience with evolving technology and greater flexibility.

Key Highlights (refer to “Customer Investments” for details) -

•Planned development and acquisition of additional renewable energy, including approximately 1,100 MW of solar generation at WPL with in-service dates in 2022-2024, approximately 275 MW of battery storage at WPL with in-service dates in 2024 and 2025, approximately 400 MW of solar generation at IPL with in-service dates in 2023 and 2024, and approximately 75 MW of battery storage at IPL with in-service dates in 2024. In addition, IPL and WPL continue to evaluate additional opportunities to add more renewable generation, including repowering of existing wind farms and additional solar generation and distributed energy resources, including community solar and energy storage systems.

•Plans to construct and/or acquire additional renewable, battery and natural gas resources to meet the requirements of MISO’s new seasonal resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements effective with the 2023/2024 MISO Planning Year.

•WPL’s completion of new solar generation in Wisconsin in 2022, including 150 MW in Wood County, 50 MW in Richland County, and 50 MW in Rock County.

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Growing customer demand - Alliant Energy’s strategy supports expanding electric and gas usage in its service territories by promoting electrification initiatives and economic development in the communities it serves.

Key Highlights -

•Alliant’s Energy’s economic development efforts resulted in being named a Top Utility in Economic Development by Site Selection Magazine for the fourth year in a row, and in 2022 being awarded the Chairman’s Award for Workforce Development Leadership by the Center for Energy Workforce Development.

•Alliant Energy continues to partner with its commercial and industrial customers to help develop renewable solutions to enhance their sustainability initiatives, including planned solar facilities in Iowa and Wisconsin.

•Alliant Energy has various development-ready sites throughout Iowa and Wisconsin, including the 1,300-acre Big Cedar Industrial Center Mega-site in Cedar Rapids, Iowa, and the 730-acre Prairie View Industrial Center Super Park in Ames, Iowa, which are rail-served ready-to-build manufacturing and industrial sites in close proximity to the regional airport and interstate freeways and access IPL’s electric services. The Big Cedar Industrial Center Mega-site also accesses Travero’s rail-served warehouse in Iowa. In addition, the Beaver Dam Commerce Park is a 520-acre ready-to-build manufacturing and industrial site in Beaver Dam, Wisconsin, with access to commercial and freight airports, interstate freeways and WPL’s electric services.

RESULTS OF OPERATIONS

Results of operations include financial information prepared in accordance with GAAP as well as utility electric margins and utility gas margins, which are not measures of financial performance under GAAP. Utility electric margins are defined as electric revenues less electric production fuel, purchased power and electric transmission service expenses. Utility gas margins are defined as gas revenues less cost of gas sold. Utility electric margins and utility gas margins are non-GAAP financial measures because they exclude other utility and non-utility revenues, other operation and maintenance expenses, depreciation and amortization expenses, and taxes other than income tax expense.

Management believes that utility electric and gas margins provide a meaningful basis for evaluating and managing utility operations since electric production fuel, purchased power and electric transmission service expenses and cost of gas sold are generally passed through to customers, and therefore, result in changes to electric and gas revenues that are comparable to changes in such expenses. The presentation of utility electric and gas margins herein is intended to provide supplemental information for investors regarding operating performance. These utility electric and gas margins may not be comparable to how other entities define utility electric and gas margin. Furthermore, these measures are not intended to replace operating income as determined in accordance with GAAP as an indicator of operating performance.

Additionally, the table below includes 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 segment 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.

Financial Results Overview - Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners were as follows (dollars in millions, except per share amounts):

Alliant Energy’s Utilities and Corporate Services net income increased by $58 million in 2022 compared to 2021. The increase was primarily due to higher revenue requirements and AFUDC from WPL capital investments and higher electric and gas margins, including the impacts of temperatures. These items were partially offset by higher depreciation expense.

Alliant Energy’s Non-utility and Parent net income decreased by $29 million in 2022 compared to 2021, primarily due to higher financing expense and the impact of the Iowa state income tax rate change.

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Operating income and a reconciliation of utility electric and gas margins to the most directly comparable GAAP measure, operating income, was as follows (in millions):

Operating Income Variances - Variances between periods in operating income for 2022 compared to 2021 were as follows (in millions):

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), were as follows:

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Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes were unchanged in 2022 compared to 2021 primarily due to increases in sales volumes to residential and commercial customers caused by changes in temperatures, offset by decreases in sales volumes to industrial customers caused by maintenance outages and labor-related disruptions at certain large customers. Alliant Energy’s retail gas sales volumes increased 14% in 2022 compared to 2021, primarily due to changes in temperatures and increases in the number of retail gas customers.

Estimated increases (decreases) to electric and gas margins from the impacts of temperatures were as follows (in millions):

Electric Sales for Resale - Electric sales for resale volume changes were largely 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 sales for resale revenues were largely offset by changes in fuel-related costs, and therefore, did not have a significant impact on electric margins.

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. Changes in these transportation/other revenues did not have a significant impact on gas margins.

Utility Electric Margin Variances - The following items contributed to increased (decreased) utility electric margins for 2022 compared to 2021 (in millions):

(a)In December 2021, the PSCW issued an order authorizing annual base rate increases of $114 million and $15 million for WPL’s retail electric and gas customers, respectively, covering the 2022/2023 forward-looking Test Period, which was based on a stipulated agreement between WPL and certain stakeholders. The key drivers for the annual base rate increases include higher retail fuel-related costs in 2022, lower excess deferred income tax benefits in 2022 and 2023 compared to 2021, and revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation. Retail electric rate changes were effective on January 1, 2022 and extend through the end of 2023. Retail gas rate changes were effective on January 1, 2022 and extended through the end of 2022. The higher fuel expense costs are recognized in electric margin and the lower amount of excess deferred income tax benefits is recognized as an increase in income tax expense.

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for 2022 compared to 2021 (in millions):

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Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for 2022 compared to 2021 (in millions):

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for 2022 compared to 2021 (in millions):

Income Taxes - Refer to Note 12 for details of effective income tax rates, including the impact of Iowa tax reform in 2022.

Preferred Dividend Requirements of IPL - Refer to Note 8 for details of the redemption of IPL’s 5.1% cumulative preferred stock in 2021, including a $5 million non-cash charge recorded in 2021 related to this transaction.

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 $250 million of common stock in 2023 through the distribution agreement for the sale from time to time of up to $225 million of common stock that was executed in December 2022, and its Shareowner Direct Plan. Alliant Energy and its subsidiaries currently expect to issue up to $1.2 billion of long-term debt in 2023. AEF has $400 million of long-term debt maturing in 2023.

•Common Stock Dividends - Alliant Energy announced a 6% increase in its targeted 2023 annual common stock dividend to $1.81 per share, which is equivalent to a quarterly rate of $0.4525 per share, beginning with the February 2023 dividend payment. The timing and amount of future dividends is subject to an approved dividend declaration 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 an increase in earnings in 2023 compared to 2022 due to impacts from increasing revenue requirements related to investments in the utility business, including WPL’s solar investments.

•Other Operation and Maintenance Expenses - Alliant Energy, IPL and WPL currently expect a decrease in other operation and maintenance expenses in 2023 compared to 2022 largely due to cost reductions resulting from operating efficiencies.

•Interest Expense - Alliant Energy, IPL and WPL currently expect an increase in interest expense in 2023 compared to 2022 due to financings completed in 2022 and planned in 2023 as discussed above, as well as expected higher interest rates.

CUSTOMER INVESTMENTS

Alliant Energy’s, IPL’s and WPL’s strategic priorities include making significant customer-focused investments toward cleaner energy and resilient and sustainable customer solutions. These priorities include:

Clean Energy Blueprint

Alliant Energy has developed a Clean Energy Blueprint, or its cleaner energy strategy, as a guide to meet customer demand for affordable, safe, reliable and sustainable energy in Iowa and Wisconsin. This strategy includes the planned development and acquisition of additional renewable energy, including approximately 1,100 MW of solar generation at WPL with in-service dates in 2022-2024, approximately 275 MW of battery storage at WPL with in-service dates in 2024 and 2025, approximately 400 MW of solar generation at IPL with in-service dates in 2023 and 2024 and approximately 75 MW of battery storage at IPL with in-service dates in 2024. In order to support reliable and sustainable energy and meet the MISO’s new seasonal resource adequacy requirements, Alliant Energy, IPL and WPL continue to evaluate additional opportunities for renewable generation, distributed energy resources and natural gas resources, as well as repower existing wind farms. Estimated capital expenditures for these planned projects for 2023 through 2026 are included in the “Renewables and battery storage” line in the construction and acquisition table in “Liquidity and Capital Resources.” These estimates include current expectations for higher costs for various projects, as supply constraints and commodity inflation continue to be prevalent in the solar market. In

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addition, Alliant Energy completed the construction and acquisition of approximately 1,200 MW of wind generation in aggregate (approximately 1,000 MW at IPL and approximately 200 MW at WPL) from 2018 through 2020.

WPL’s Solar Generation and Distributed Energy Resources - In June 2021, WPL received an order from the PSCW for its first CA authorizing WPL to acquire, own, and operate 675 MW of new solar generation in the following Wisconsin counties: Grant (200 MW), Sheboygan (150 MW), Wood (150 MW), Jefferson (75 MW), Richland (50 MW) and Rock (50 MW). In June 2022, WPL received an order from the PSCW for its second CA authorizing WPL to acquire, construct, own, and operate up to 414 MW of new solar generation in the following Wisconsin counties: Dodge (150 MW), Waushara (99 MW), Rock (65 MW), Grant (50 MW) and Green (50 MW). The Wood, Richland and Rock County projects were placed in service in 2022, and the remaining projects in the first and second CAs are expected to be placed in service in 2023 and 2024. The 1,089 MW of new solar generation is expected to replace energy and capacity being eliminated with the planned retirements of the coal-fired Edgewater Generating Station (414 MW) by June 1, 2025, and Columbia Units 1 and 2 (595 MW in aggregate) by June 1, 2026, which are the last coal-fired EGUs at WPL. The retirement of these coal-fired EGUs supports Alliant Energy’s strategy, which is focused on meeting its customers’ energy needs in an affordable, safe, reliable and sustainable manner.

In September 2022, WPL filed a request with the PSCW for approval to construct, own and operate 175 MW of battery storage, with 100 MW and 75 MW at the Grant County and Wood County solar projects, respectively, with in-service dates in 2024. In January 2023, WPL filed a request with the PSCW for approval to construct, own and operate approximately 99 MW of battery storage at the Edgewater Generating Station, with an in-service date in 2025.

IPL’s Solar Generation and Distributed Energy Resources - In November 2021, IPL filed for advance rate-making principles with the IUB for up to 400 MW of solar generation with in-service dates in 2023 and 2024 and 75 MW of battery storage in 2024. The advance rate-making principles filing included requests for a fixed cost cap, including AFUDC and transmission upgrade costs among other costs, and a return on common equity of 11.40%, and proposed that a portion of the construction be financed by tax equity partners. In September 2022, IPL provided the IUB with a summary of the Inflation Reduction Act of 2022, as well as an economic analysis indicating full ownership for these planned solar and battery storage projects is currently expected to result in more cost benefits for its customers compared to previous plans to utilize tax equity financing.

In November 2022, the IUB denied these advance rate-making principles filings and IPL requested reconsideration of the IUB’s decision. In December 2022, the IUB issued an order granting reconsideration of 200 MW of solar generation, and denied reconsideration of the other 200 MW of solar generation and 75 MW of battery storage. In January 2023, IPL filed additional information with the IUB related to the 400 MW of solar generation and 75 MW of battery storage, including a revised fixed cost cap of $1,845/kilowatt, based on updated materials, labor and shipping costs. In addition, IPL filed a request for judicial review in January 2023 regarding the denial of advance rate-making principles for the other 200 MW of solar generation and 75 MW of battery storage. In February 2023, the IUB issued an order stating that it will not issue a decision on the advance rate-making principles for the 200 MW of solar that was granted reconsideration until it receives clarity regarding its authority to issue the advance rate-making principles while the judicial review is also pending. IPL believes these solar generation and battery storage projects are in the best interests of its customers, and if advance rate-making principles are not approved by the IUB or approval by the IUB is expected to be delayed, IPL may decide to proceed with constructing the solar generation and battery storage subject to other applicable approvals (such as a GCU Certificate), and seek recovery in future rate reviews.

The 400 MW of new solar generation and 75 MW of battery storage would help replace a portion of the energy and capacity expected to be eliminated with the planned retirement of the coal-fired Lansing Generating Station (275 MW) in the first half of 2023 and the reduction of energy and capacity resulting from the December 2021 fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas. In addition, IPL’s plans include additional renewables and distributed energy resources, including community solar and energy storage systems, to add energy and capacity.

New MISO Seasonal Resource Adequacy Process - In August 2022, FERC approved MISO’s proposal to change its resource adequacy process establishing capacity planning reserve margin and capacity accreditation requirements effective with the 2023/2024 MISO Planning Year, to help ensure the reliability of electricity in the MISO region. The process will change from the current Summer-based annual construct to four distinct seasons to help ensure the continued reliability of the electric transmission grid throughout each year. FERC’s approval also establishes planning reserve margin requirements for all market participants on a seasonal basis and determines a seasonal accredited capacity value for certain classes of generating resources, including higher accredited capacity for wind generation during the Spring, Fall and Winter seasons and higher accredited capacity for solar generation during the Summer season. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters, but plan to construct and/or acquire additional renewable, battery and natural gas resources to meet the requirements of the new seasonal resource adequacy process and have reflected the estimated capital expenditures for these projects in the “Renewables and battery storage” and “Other” Generation lines in the construction and acquisition table in “Liquidity and Capital Resources.”

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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:

(a)Upon WPSC’s exercise of its options, 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 either WPSC or its affiliated utility, Wisconsin Electric Power Company, 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 in the next several years. IPL currently expects to retire the coal-fired Lansing Generating Station (275 MW) in the first half of 2023, and fuel switch or retire Prairie Creek Units 1 and 3 (65 MW in aggregate) by December 31, 2025. WPL currently expects to retire the coal-fired Edgewater Generating Station (414 MW) by June 1, 2025, and Columbia Units 1 and 2 (595 MW in aggregate) by June 1, 2026. 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 these EGUs.

Environmental Stewardship - Alliant Energy’s environmental stewardship is focused on meeting its customers’ energy needs affordably, safely, reliably and sustainably. Alliant Energy proactively considers future environmental compliance requirements and proposed regulations in its planning, decision-making, construction and ongoing operations activities. Alliant Energy is focused on executing a long-term strategy to deliver reliable and affordable energy with lower emissions independent of changing policies and political landscape. To achieve these long-term goals, Alliant Energy will transition away from coal-fired EGUs by incorporating renewable energy, distributed energy resources, energy efficiency, demand response, natural gas-fired EGUs and other technologies such as energy storage. Alliant Energy’s voluntary environmental-related goals and achievements include the following:

•Exceeded its 2020 targets by reducing air emissions for sulfur dioxide by over 90%, nitrogen oxides by over 80% and mercury by over 90% from 2005 levels.

•By 2030, reduce CO2 emissions by 50% from its owned fossil-fueled EGUs and reduce electric utility water supply by 75% from 2005 levels, and transition 100% of its owned light-duty fleet vehicles to be electric, as well as partner to plant more than 1 million trees by the end of 2030.

•By 2040, eliminate all coal-fired EGUs from its generating fleet.

•By 2050, achieve an aspirational goal of net-zero CO2 emissions from the electricity it generates.

Future updates to sustainable energy plans and attaining these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories.

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 enabling distributed energy solutions with higher capacity lines. Gas system investments will focus on pipeline replacement to ensure safety and pipeline expansion to support reliability and economic development. Estimated capital expenditures for expected and current electric and gas distribution infrastructure projects for 2023 through 2026 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 is currently installing 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 among financially disadvantaged customers and communities.

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.

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Gas Pipeline Safety - The Pipeline and Hazardous Materials Safety Administration published various final rules from 2019 through 2022 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, with identified remediation efforts to be completed by July 2035. In anticipation of these rule changes, Alliant Energy, IPL and WPL have been proactively replacing certain of IPL’s transmission pipelines, making modifications to certain of WPL’s transmission pipelines, and updating practices for assessment and operation of these 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, customer self-service and telework. Estimated capital expenditures for expected and current technology projects for 2023 through 2026 are included in the “Other” line in the construction and acquisition expenditures table in “Liquidity and Capital Resources.”

Non-utility business - Alliant Energy continues to explore growth of its Travero businesses and other limited scope opportunities outside of, but complementary to, Alliant Energy’s core utility business. This non-utility strategy continues to evolve through exploration of modest strategic opportunities that are accretive to earnings and cash flows.

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.

WPL’s Retail Electric and Gas Rate Reviews (2022/2023 Forward-looking Test Period) - In December 2021, the PSCW issued an order authorizing annual base rate increases of $114 million and $15 million for WPL’s retail electric and gas customers, respectively, covering the 2022/2023 forward-looking Test Period, which was based on a stipulated agreement between WPL and certain stakeholders. The key drivers for the annual base rate increases include higher retail fuel-related costs in 2022, lower excess deferred income tax benefits in 2022 and 2023 and revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation. In addition, the PSCW authorized WPL to receive a recovery of and a return on the remaining net book value of Edgewater Unit 5 through 2023. Retail electric rate changes were effective on January 1, 2022 and extend through the end of 2023. Retail gas rate changes were effective from January 1, 2022 through the end of 2022.

In December 2022, the PSCW issued an order authorizing an additional annual base rate increase of $9 million for WPL’s retail gas customers, covering the 2023 forward-looking Test Period, which reflects changes in weighted average cost of capital, updated depreciation rates and modifications to certain regulatory asset and regulatory liability amortizations. These retail gas rate changes were effective on January 1, 2023 and extend through the end of 2023.

WPL’s settlement extends, with certain modifications, an earnings sharing mechanism through 2023. Under the earnings sharing mechanism, WPL will defer a portion of its earnings if its annual regulatory return on common equity exceeds 10.25% during the 2022/2023 Test Period. WPL must defer 50% of its excess earnings between 10.25% and 10.75%, and 100% of any excess earnings above 10.75%. Through 2023, any such deferral is required to be offset against the remaining net book value of Edgewater Unit 5, which is currently expected to be retired by June 1, 2025.

WPL’s Retail Fuel-related Rate Filing (2021 Forward-looking Test Period) - In August 2022, the PSCW authorized WPL to collect $37 million in 2023 from its retail electric customers, plus interest, for an under-collection of fuel-related costs incurred by WPL in 2021 that were higher than fuel-related costs used to determine rates for such period.

WPL’s Retail Fuel-related Rate Filing (2023 Forward-looking Test Period) - In December 2022, the PSCW authorized WPL to collect $47 million in higher rates in 2023 from its retail electric customers to reflect an increase in expected fuel-related costs for 2023 compared to WPL’s approved 2022 fuel-related costs.

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Rate Review Details - Details related to IPL’s and WPL’s key jurisdictions were as follows:

(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 recovered through IPL’s renewable energy rider mechanism include construction costs incurred to fund IPL’s 1,000 MW of wind generation facilities placed in service in 2019 and 2020 (11.00% return on common equity), production tax credit carryforwards for the 1,000 MW of wind generation facilities (5.00% return on common equity) and certain transmission facilities classified as intangible assets (9.50% return on common equity), and were calculated using a 13-month average.

(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.

Planned Rate Reviews - WPL currently expects to file a retail electric and gas rate review with the PSCW in the second quarter of 2023 for the 2024/2025 forward-looking Test Period. The key drivers for the anticipated filing include revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation and battery storage. Any rate changes granted from this pending request are expected to be effective on January 1, 2024, with a decision from the PSCW expected by the end of 2023.

IPL currently expects to file a retail electric and gas rate review with the IUB by the first half of 2024. The key drivers for the anticipated filing include revenue requirement impacts of increasing electric and gas rate base, including investments in solar generation and battery storage.

LEGISLATIVE MATTERS

In August 2022, the Inflation Reduction Act of 2022 was enacted. The most significant provisions of the new 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 eligible for solar projects, a new stand-alone investment tax credit for battery storage projects and the right to transfer future renewable credits to other corporate taxpayers. The new legislation also includes 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 currently expect to utilize various provisions of the new legislation to enhance the tax benefits expected from their announced solar and battery storage projects, including transferring the future tax credits from such projects to other corporate taxpayers and opting to retain full ownership of such projects instead of financing a portion of the projects with tax equity partners. Compared to previous plans to utilize tax equity financing, the impact of these changes is expected to result in more cost benefits for IPL's and WPL's customers, higher rate base amounts, additional financing needs expected to be satisfied with additional long-term debt and common stock issuances, and improvements in long-term cash flows over the life of the solar and battery storage projects.

Refer to Note 12 for discussion of Iowa tax reform enacted in March 2022.

In November 2021, the Infrastructure Investment and Jobs Act (IIJA Act) was enacted. The most significant provisions of the IIJA Act for Alliant Energy relate to a variety of infrastructure-related priorities, including transportation, environmental, energy and broadband infrastructure. In addition, the IIJA Act is intended to accelerate research, development, demonstration and deployment of carbon-free technologies, including hydrogen and carbon capture and storage.

In March 2021, the American Rescue Plan Act of 2021 (Act) was enacted. The most significant provision of the Act for Alliant Energy is reduced minimum pension plan funding requirements, which Alliant Energy adopted in August 2021. The Act also

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provides additional funding to the Low Income Home Energy Assistance Program, which assists certain of Alliant Energy’s customers with managing their energy costs, as well as provides financial support for certain of Alliant Energy’s residential, small business and non-profit customers.

In March 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted. The most significant provision of the CARES Act for Alliant Energy relates to an acceleration of refunds of existing alternative minimum tax credits to increase liquidity. In 2020, Alliant Energy received $11 million of credits that otherwise would have been received in 2021 and 2022. In addition, Alliant Energy deferred certain 2020 payroll taxes to 2021 and 2022. The CARES Act also provides additional funding to the Low Income Home Energy Assistance Program, which assists certain of Alliant Energy’s customers with managing their energy costs, as well as financial support for certain of Alliant Energy’s residential, small business and non-profit customers.

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, 2022, Alliant Energy had $20 million of cash and cash equivalents, $358 million ($148 million at the parent company, $100 million at IPL and $110 million at WPL) of available capacity under the single revolving credit facility and $30 million of 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. IPL and WPL expect to maintain capital structures consistent with the authorized levels approved by regulators. Capital structures as of December 31, 2022 were as follows (Common Equity (CE); Long-term Debt (including current maturities) (LD); Short-term Debt (SD)):

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 on 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 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 IUB 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, pension and OPEB obligations and the sales of accounts receivable program.

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.

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Cash Flows - Selected information from the cash flows statements was as follows (in millions):

Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for 2022 compared to 2021 (in millions):

Income Tax Payments and Refunds - Income tax (payments) refunds were as follows (in millions):

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 refunds 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 12 for discussion of the carryforward positions.

As discussed in “Legislative Matters,” the Inflation Reduction Act of 2022 provides the right to transfer future renewable tax credits to other corporate taxpayers, which is expected to result in future cash flows from operating activities for Alliant Energy, IPL and WPL beginning as early as 2023.

Pension Plan Contributions - Alliant Energy, IPL and WPL currently expect to make $12 million, $1 million and $10 million of pension plan contributions in 2023, respectively, based on the funded status and assumed return on assets for each plan as of the December 31, 2022 measurement date. Refer to Note 13(a) for discussion of pension plan contributions in 2022 and the current funded levels of pension plans.

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for 2022 compared to 2021 (in millions):

(a)Largely due to higher expenditures for WPL’s solar generation.

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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 regulatory requirements, changing legislation, not obtaining favorable and acceptable regulatory approval on certain projects, improvements in technology and improvements to ensure resiliency and reliability of the electric and gas distribution systems. 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. The table below summarizes anticipated construction and acquisition expenditures (in millions), which are focused on the transition to cleaner energy and strengthening the resiliency and reliability of IPL’s and WPL’s electric grid. 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 projects impacting construction and acquisition plans related to the utility business.

Renewables and Battery Storage - Alliant Energy, IPL and WPL continue to evaluate potential impacts from cost pressures prevalent in the solar generation and battery storage markets on the timing and estimated costs for IPL’s and WPL’s planned development and acquisition of additional renewable energy, which could impact their anticipated future construction and acquisition expenditures. Refer to “Customer Investments” for further discussion of regulatory filings with the IUB and PSCW related to future renewable and battery storage projects.

West Riverside Options - WPL entered into agreements with neighboring utilities that provide them options to purchase a partial ownership interest in West Riverside. Upon exercise of such options, WPL will receive proceeds from the sale. Refer to “Customer Investments” for additional information, including timing for the actual and potential exercise of options.

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for 2022 compared to 2021 (in millions):

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 2021, IPL received authorization from FERC to issue securities in 2022 and 2023 as follows (in millions):

State Regulatory Financing Authorizations - In 2017, WPL received authorization from the PSCW to have up to $400 million of short-term borrowings and/or letters of credit outstanding at any time through the earlier of the expiration date of WPL’s credit facility agreement (including extensions) or December 2024. In February 2023, WPL received authorization from the PSCW to issue up to $1.2 billion of long-term debt securities in aggregate through December 2025.

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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 2023. 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 2023.

Common Stock Issuances - Refer to Note 7 for discussion of common stock issuances by Alliant Energy in 2021 and 2022, and “Results of Operations” for discussion of expected issuances of common stock in 2023.

Short-term Debt - In 2021, Alliant Energy, IPL and WPL entered into a single revolving credit facility agreement, which expires in December 2026 and is discussed in Note 9(a). There are currently 13 lenders that participate in the credit facility, with respective commitments ranging from $20 million to $130 million. Subject to certain conditions, Alliant Energy, IPL and WPL may exercise two extension options, each extending the maturity date by one year. The credit facility has a provision to expand the facility size up to an additional $300 million, for a potential total commitment of $1.3 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.

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, 2022 were as follows:

The debt component of the capital ratios includes, when applicable, long- and short-term debt (excluding non-recourse debt and hybrid securities 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 9(b) for discussion of issuances and retirements of long-term debt in 2022 and 2023, and “Results of Operations” for discussion of expected issuances of long-term debt in 2023. In 2021, IPL issued $300 million of 3.1% senior debentures due 2051, and the net proceeds from the issuance were used by IPL to retire its cumulative preferred stock in 2021 and for general corporate purposes. In 2021, WPL issued $300 million of 1.95% green bond debentures due 2031, and an amount in excess of the net proceeds was disbursed for the construction and development of WPL’s wind and solar EGUs.

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:

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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 and 2022 (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 Note 15 for additional information on ratings triggers for commodity contracts accounted for as derivatives.

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 2023. IPL currently expects to amend and extend the purchase commitment. In 2022 and 2021, 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, 2022, various guarantees and indemnifications are outstanding related to Alliant Energy’s cash equity ownership interest in a non-utility wind farm and prior divestiture activities. Refer to Note 17(d) for additional information.

Certain Financial Commitments -

Contractual Obligations - Alliant Energy, IPL and WPL have various long-term contractual obligations as of December 31, 2022, which include long-term debt maturities in Note 9(b), operating and finance leases in Note 10, capital purchase obligations in Note 17(a), and other purchase obligations in Note 17(b). At December 31, 2022, Alliant Energy, IPL and WPL had no uncertain tax positions recorded as liabilities. Refer to Note 13(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, 2022, 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 15 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

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margins. WPL’s retail electric margins have exposure 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 all counterparties and employ credit risk controls, such as letters of credit, 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. Refer to Note 13(a) for details of the securities held by their pension and OPEB plans. Refer to “Critical Accounting Policies and Estimates” for the impact on retirement plan costs of changes in the rate of returns earned by plan assets.

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, 2022, Alliant Energy’s, IPL’s and WPL’s annual pre-tax expense would increase by approximately $11 million, $1 million and $3 million, respectively. Refer to Notes 5(b) and 9 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 Policies and Estimates” for the impacts of changes in discount rates on retirement plan obligations and costs.

Critical Accounting Policies and 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 policies and 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 policies and estimates with the Audit Committee of the Board of Directors. Refer to Note 1 for additional discussion of accounting policies and 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.

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 authorities 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. Note 2 provides details of the nature and amounts of regulatory assets and regulatory liabilities assessed at December 31, 2022.

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 2022 include estimates of qualifying deductions for repairs expenditures and allocation of mixed service costs 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 12 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

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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 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, 2022. Based on projections of current and future taxable income, Alliant Energy, IPL and WPL plan to utilize all of these carryforwards prior to their expiration. Federal credit carryforwards generated from 2004 through 2008 are expected to be utilized within five years of expiration. All other federal credit carryforwards are expected to be utilized 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.

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 - Alliant Energy’s, IPL’s and WPL’s long-lived assets within their regulated operations that were assessed for impairment and/or plant abandonment in 2022 included IPL’s and WPL’s generating units subject to early retirement and WPL’s solar generation projects recently completed and under construction.

Generating Units Subject to Early Retirement - Alliant Energy, IPL and WPL evaluate future plans for their electric generation fleet and have announced the early retirement of certain EGUs. When it becomes probable that an EGU will be retired before the end of its useful life, Alliant Energy, IPL and WPL must assess whether the EGU meets the criteria to be considered probable of abandonment. EGUs that are considered probable of abandonment generally have material remaining net book values and are expected to cease operations in the near term significantly before the end of their original estimated useful lives. If an EGU meets such criteria to be considered probable of abandonment, Alliant Energy, IPL and WPL must assess the probability of full recovery of the remaining carrying value of such EGU. If it is probable that regulators will not allow full recovery of and a full return on the remaining net book value of the abandoned EGU, an impairment charge is recognized equal to the difference between the remaining carrying value and the present value of the future revenues expected from the abandoned EGU.

Alliant Energy and IPL concluded that Lansing (expected to be retired in the first half of 2023), and Alliant Energy and WPL concluded that Edgewater Unit 5 (expected to be retired by June 1, 2025) and Columbia Units 1 and 2 (expected to be retired by June 1, 2026), met the criteria to be considered probable of abandonment as of December 31, 2022. IPL and WPL are currently allowed a full recovery of and a full return on its respective EGUs from both its retail and wholesale customers, and as a result, Alliant Energy, IPL and WPL concluded that no impairment was required as of December 31, 2022. Upon retirement of Lansing, which is currently expected in the first half of 2023, IPL anticipates reclassifying the remaining net book value, which was $233 million as of December 31, 2022, from property, plant and equipment to a regulatory asset on Alliant Energy’s and IPL’s balance sheets. Continued recovery of the remaining net book value of Lansing is expected to be addressed in future rate reviews. Alliant Energy, IPL and WPL evaluated their other EGUs that are subject to early retirement and determined that no other EGUs met the criteria to be considered probable of abandonment as of December 31, 2022. Note 3 provides additional details of these assets anticipated to be retired early.

WPL’s Solar Generation Projects Recently Completed and Under Construction - As discussed in “Customer Investments,” WPL previously received authorization from the PSCW to acquire, construct, own and/or operate approximately 1,100 MW of new solar generation, which includes various projects in various Wisconsin counties. In 2022, WPL completed the construction of three solar projects, and the remaining solar projects are currently expected to be placed in service in 2023 and 2024. Alliant Energy and WPL review property, plant and equipment 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 WPL is disallowed recovery of any portion of, or is only allowed a partial return on, the carrying value of the solar generation projects recently completed or under construction, then an impairment charge is recognized.

In July 2021, WPL notified the PSCW that it expected estimated construction costs associated with approximately 675 MW of new solar generation will exceed amounts previously approved by the PSCW by approximately 7-10%. In addition, the prior authorization received from the PSCW for approximately 1,100 MW of new solar generation assumed that a portion of the construction costs would be financed by a tax equity partner. Following the enactment of the Inflation Reduction Act of 2022, WPL determined that retaining full ownership of the approximately 1,100 MW of new solar generation is expected to result in more cost benefits for its customers. Alliant Energy and WPL no longer expect their solar generation project construction costs to be financed with capital from tax equity partners, which would result in higher rate base amounts compared to those previously approved by the PSCW for WPL’s planned approximately 1,100 MW of solar generation. Alliant Energy and WPL concluded that there was not a probable disallowance of anticipated higher rate base amounts as of December 31, 2022 given construction costs were reasonably and prudently incurred and full ownership of WPL’s planned solar generation is expected to result in more cost benefits for WPL's customers.

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Unbilled Revenues - Unbilled revenues are primarily associated with utility operations. Energy sales to individual customers are based on the reading of customers’ meters, which occurs on a systematic basis throughout the month. Amounts of energy delivered to customers since the date of the last meter reading are estimated at the end of each reporting period and the corresponding estimated unbilled revenue is recorded. The unbilled revenue is based on estimates of daily system demand volumes, customer usage by class, temperature impacts, line losses and the most recent customer rates. Such process involves the use of various judgments and assumptions and significant changes in these judgments and assumptions could have a material impact on results of operations. As of December 31, 2022, unbilled revenues related to Alliant Energy’s utility operations were $247 million ($132 million at IPL and $115 million at WPL).

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):

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.

Effective January 1, 2020 upon the adoption of the new accounting standard for credit losses, certain contingencies, such as Alliant Energy Resources, LLC’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, require estimation each reporting period of the expected credit losses on those contingencies. These estimates require significant judgment and result in recognition of a credit loss liability sooner than the previous accounting standards, which required recognition when the contingency became probable and could be reasonably estimated based on then currently available information. With respect to Alliant Energy’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, the most significant judgments in determining the credit loss liability were the estimate of the exposure under the guarantees and the methodology used for calculating the credit loss liability. As of December 31, 2022, Alliant Energy currently estimates the exposure to be a portion of the known partnership abandonment obligations. The methodology used to determine the credit loss liability considers both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts. Factors considered include market and external data points, the creditworthiness of the other partners, Whiting Petroleum’s emergence from bankruptcy in the third quarter of 2020 as well as subsequent bankruptcy developments, payments by Whiting Petroleum related to abandonment obligations, forecasted cash flow expenditures associated with the abandonment obligations based on information made available to Alliant Energy, and Whiting Petroleum’s business combination with Oasis Petroleum Inc. in the third quarter of 2022. Note 1(l) provides discussion of the adoption of the new accounting standard for credit losses.

Note 17 provides further discussion of contingencies assessed at December 31, 2022 that may have a material impact on financial condition and results of operations, including various pending legal proceedings, guarantees and indemnifications.