UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2021

or

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number

ALLIANT ENERGY CORPORATION

(a Wisconsin Corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 1-9894

IRS Employer Identification Number - 39-1380265

INTERSTATE POWER & LIGHT COMPANY

(an Iowa corporation)

Alliant Energy Tower

Cedar Rapids, Iowa 52401

Telephone (319) 786-4411

Commission File Number - 1-4117

IRS Employer Identification Number - 42-0331370

WISCONSIN POWER & LIGHT COMPANY

(a Wisconsin corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 0-337

IRS Employer Identification Number - 39-0714890

This combined Form 10-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-K relating to Interstate Power and Light Company and Wisconsin Power and Light Company is filed by each such registrant on its own behalf. Each of Interstate Power and Light Company and Wisconsin Power and Light Company makes no representation as to information relating to registrants other than itself.

Securities registered pursuant to Section 12(b) of the Act:

Alliant Energy Corporation, Common Stock, $0.01 Par Value, Trading Symbol LNT, Nasdaq Global Select Market

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports) and (2) has been subject to such filing requirements for the past 90 days.

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, accelerated filer, non-accelerated filer, smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Alliant Energy Corporation - Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company ☐ Emerging Growth Company ☐

Interstate Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐

Wisconsin Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Alliant Energy Corporation ☐

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (§ 15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.

Alliant Energy Corporation ☒

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

The aggregate market value of the voting and non-voting common equity held by nonaffiliates as of June 30, 2021:

Alliant Energy Corporation - $13.9 billion

Interstate Power and Light Company - $0

Wisconsin Power and Light Company - $0

Number of shares outstanding of each class of common stock as of January 31, 2022:

Alliant Energy Corporation, Common Stock, $0.01 par value, 250,478,681 shares outstanding

Interstate Power and Light Company, Common Stock, $2.50 par value, 13,370,788 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

Wisconsin Power and Light Company, Common Stock, $5 par value, 13,236,601 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Proxy Statement relating to Alliant Energy Corporation’s 2022 Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.

TABLE OF CONTENTS

DEFINITIONS

The following abbreviations or acronyms used in this report are defined below:

FORWARD-LOOKING STATEMENTS

Statements contained in this report that are not of historical fact are forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified as such because the statements include words such as “may,” “believe,” “expect,” “anticipate,” “plan,” “project,” “will,” “projections,” “estimate,” or other words of similar import. Similarly, statements that describe future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. Some, but not all, of the risks and uncertainties of Alliant Energy, IPL and WPL that could materially affect actual results include:

• the impact of penalties or third-party claims related to, or in connection with, a failure to maintain the security of personally identifiable information, including associated costs to notify affected persons and to mitigate their information security concerns;

• the direct or indirect effects resulting from terrorist incidents, including physical attacks and cyber attacks, or responses to such incidents;

• the impact of customer- and third party-owned generation, including alternative electric suppliers, in IPL’s and WPL’s service territories on system reliability, operating expenses and customers’ demand for electricity;

• the impact of energy efficiency, franchise retention and customer disconnects on sales volumes and margins;

• the impact that price changes may have on IPL’s and WPL’s customers’ demand for electric, gas and steam services and their ability to pay their bills;

• IPL’s and WPL’s ability to obtain adequate and timely rate relief to allow for, among other things, the recovery of and/or the return on costs, including fuel costs, operating costs, transmission costs, deferred expenditures, deferred tax assets, tax expense, capital expenditures, and remaining costs related to EGUs that may be permanently closed and certain other retired assets, decreases in sales volumes, earning their authorized rates of return, and the payments to their parent of expected levels of dividends;

• federal and state regulatory or governmental actions, including the impact of legislation, and regulatory agency orders;

• the ability to utilize tax credits and net operating losses generated to date, and those that may be generated in the future, before they expire;

• the impacts of changes in the tax code, including tax rates, minimum tax rates, and adjustments made to deferred tax assets and liabilities;

• the ability to complete construction of renewable generation and storage projects within the cost targets set by regulators due to cost increases of materials, equipment and commodities including due to tariffs, labor issues or supply shortages, the ability to successfully resolve warranty issues or contract disputes, the ability to achieve the expected level of tax benefits based on tax guidelines and project costs, and the ability to efficiently utilize the renewable generation and storage project tax benefits for the benefit of customers;

• employee workforce factors, including changes in key executives, ability to hire and retain employees with specialized skills, ability to create desired corporate culture, collective bargaining agreements and negotiations, work stoppages or restructurings;

• any material post-closing payments related to any past asset divestitures, including the sale of Whiting Petroleum, which could result from, among other things, indemnification agreements, warranties, guarantees or litigation;

• weather effects on results of utility operations;

• the direct or indirect effects resulting from the ongoing COVID-19 pandemic and the spread of variant strains, including any vaccine mandates and testing requirements, on sales volumes, margins, operations, employees, labor markets, contractors, vendors, the ability to complete construction projects, supply chains, customers’ inability to pay bills, suspension of disconnects, the market value of the assets that fund pension plans and the potential for additional funding requirements, the ability of counterparties to meet their obligations, compliance with regulatory requirements, the ability to implement regulatory plans, economic conditions and access to capital markets;

• issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits, the CCR rule, future changes in environmental laws and regulations, including federal, state or local regulations for CO2 emissions reductions from new and existing fossil-fueled EGUs, and litigation associated with environmental requirements;

• increased pressure from customers, investors and other stakeholders to more rapidly reduce CO2 emissions;

• the ability to defend against environmental claims brought by state and federal agencies, such as the EPA, state natural resources agencies or third parties, such as the Sierra Club, and the impact on operating expenses of defending and resolving such claims;

• continued access to the capital markets on competitive terms and rates, and the actions of credit rating agencies;

• inflation and interest rates;

• disruptions to the supply of materials, equipment and commodities needed to construct solar generation and storage projects, including due to shortages, labor issues or transportation issues, which may impact the ability to meet capacity requirements and result in increased capacity expense;

• possible changes to MISO’s methodology establishing capacity planning reserve margin and capacity accreditation requirements that may impact how and when new generating facilities such as IPL’s and WPL’s additional solar generation may be accredited with energy capacity and may require IPL and WPL to adjust their current resource plans, the need to add resources to comply with MISO’s proposal, or procure capacity in the market whereby such costs might not be recovered in rates;

• changes in the price of delivered natural gas, transmission, purchased electricity and coal due to shifts in supply and demand caused by market conditions and regulations;

• disruptions in the supply and delivery of natural gas, purchased electricity and coal;

• the direct or indirect effects resulting from breakdown or failure of equipment in the operation of electric and gas distribution systems, such as mechanical problems and explosions or fires, and compliance with electric and gas transmission and distribution safety regulations, including regulations promulgated by the Pipeline and Hazardous Materials Safety Administration;

• issues related to the availability and operations of EGUs, including start-up risks, breakdown or failure of equipment, availability of warranty coverage for equipment breakdowns or failures; performance below expected or contracted levels of output or efficiency, operator error, employee safety, transmission constraints, compliance with mandatory reliability standards and risks related to recovery of resulting incremental costs through rates;

• impacts that excessive heat, excessive cold, storms or natural disasters may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities or on the operations of Alliant Energy’s investments;

• Alliant Energy’s ability to sustain its dividend payout ratio goal;

• changes to costs of providing benefits and related funding requirements of pension and OPEB plans due to the market value of the assets that fund the plans, economic conditions, financial market performance, interest rates, timing and form of benefits payments, life expectancies and demographics;

• material changes in employee-related benefit and compensation costs;

• risks associated with operation and ownership of non-utility holdings;

• changes in technology that alter the channels through which customers buy or utilize Alliant Energy’s, IPL’s or WPL’s products and services;

• impacts on equity income from unconsolidated investments from valuations and potential changes to ATC’s authorized return on equity;

• impacts of IPL’s future tax benefits from Iowa rate-making practices, including deductions for repairs expenditures, allocation of mixed service costs and state depreciation, and recoverability of the associated regulatory assets from customers, when the differences reverse in future periods;

• changes to the creditworthiness of counterparties with which Alliant Energy, IPL and WPL have contractual arrangements, including participants in the energy markets and fuel suppliers and transporters;

• current or future litigation, regulatory investigations, proceedings or inquiries;

• reputational damage from negative publicity, protests, fines, penalties and other negative consequences resulting in regulatory and/or legal actions;

• the effect of accounting standards issued periodically by standard-setting bodies;

• the ability to successfully complete tax audits and changes in tax accounting methods with no material impact on earnings and cash flows; and

• other factors listed in MDA and Item 1A Risk Factors.

Alliant Energy, IPL and WPL each assume no obligation, and disclaim any duty, to update the forward-looking statements in this report, except as required by law.

WEBSITE ACCESS TO REPORTS

Alliant Energy, IPL and WPL make their periodic and current reports, and amendments to those reports, available, free of charge, on Alliant Energy’s website at www.alliantenergy.com/investors on the same day as such material is electronically filed with, or furnished to, the SEC. Alliant Energy, IPL and WPL are not including the information contained on Alliant Energy’s website as a part of, or incorporating it by reference into, this report.

PART I

This report 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. Unless otherwise noted, the information herein excludes discontinued operations for all periods presented. The terms “we,” “our” and “us” used in this report refer collectively to Alliant Energy, IPL and WPL.

A. GENERAL

Alliant Energy maintains its principal executive offices in Madison, Wisconsin. Alliant Energy operates as a regulated investor-owned public utility holding company, and its purpose-driven strategy is to serve its customers and build strong communities. Alliant Energy’s primary focus is to provide regulated electric and natural gas service to approximately 985,000 electric and approximately 425,000 natural gas customers in the Midwest through its two public utility subsidiaries, IPL and WPL. The primary first tier wholly-owned subsidiaries of Alliant Energy are as follows:

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. IPL provides utility services to incorporated communities as directed by the IUB and utilizes non-exclusive franchises, which cover the use of public right-of-ways for utility facilities in incorporated communities for a maximum term of 25 years. At December 31, 2021, IPL supplied electric and natural gas service to approximately 500,000 and 225,000 retail customers, respectively, in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

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. WPL operates in municipalities pursuant to permits of indefinite duration and state statutes authorizing utility operation in areas annexed by a municipality. At December 31, 2021, WPL supplied electric and natural gas service to approximately 485,000 and 200,000 retail customers, respectively. WPL also sells electricity to wholesale customers in Wisconsin.

3) CORPORATE SERVICES - provides administrative services to Alliant Energy, IPL, WPL and AEF.

4) AEF - Alliant Energy’s non-utility holdings are organized under AEF, which manages a portfolio of wholly-owned subsidiaries and additional holdings, including the following distinct platforms:

ATI - currently holds all of Alliant Energy’s interest in ATC Holdings. ATC Holdings is comprised of a 16% ownership interest in ATC and a 20% ownership interest in ATC Holdco LLC. ATC is an independent, for-profit, transmission-only company. ATC Holdco LLC holds Duke-American Transmission Company, LLC, a joint venture between Duke Energy Corporation and ATC, that owns electric transmission infrastructure in North America.

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

Non-utility Wind Farm - includes a 50% cash equity ownership interest in a 225 MW non-utility wind farm located in Oklahoma.

Sheboygan Falls Energy Facility - is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025.

Travero - is a diversified supply chain solutions company, including a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

B. INFORMATION RELATING TO ALLIANT ENERGY ON A CONSOLIDATED BASIS

1) HUMAN CAPITAL MANAGEMENT - Alliant Energy’s core purpose is to serve customers and build strong communities. We constantly strive to attract, retain and develop a diverse and qualified workforce of high-performing employees, and create and foster an environment of inclusion and belonging for all employees.

Employees - At December 31, 2021, Alliant Energy, IPL and WPL had the following full- and part-time employees:

The majority of IPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) collective bargaining agreement, which expires on August 31, 2024. All of WPL’s bargaining unit employees are covered by the International Brotherhood of Electrical Workers Local 965 collective bargaining agreement, which expires on May 31, 2022.

Safety - Safety is integral to our company’s culture. It is one of our Values – “Live safety. Everyone. Always. Our first priority is that nobody gets hurt.” Alliant Energy is committed to providing a safe environment for our employees, visitors, customers, contractors, vendors and the communities in which we live and work.

We focus on the proactive management of our safety performance. Our comprehensive behavioral safety-based program consists of leading indicators, lagging indicators and targeted focus programs. We utilize a formal safety management system to capture and track best practices, near misses, job site briefings, safety observations, safety conversations and any unsafe conditions. This system provides the insights needed to help drive a positive safety culture and help ensure compliance with safety rules, processes and procedures. We also use this system to broadly share lessons learned in support of shaping the mindsets and behaviors needed to help prevent similar events from occurring elsewhere. Collectively, this information is used to evaluate the safety performance of the executive and management teams related to their goals, and safety metrics are factored into short-term incentive awards.

We maintain executive and local safety leadership teams to establish our safety vision, strategy and priorities, and ensure education and recognition of employee actions that improve our safety culture. This leadership provides strong support for sustained growth of both employee and public safety programs and initiatives.

Public safety is equally important as we interact with our customers to provide energy to their homes and businesses. We offer awareness campaigns, natural gas and electric public safety presentations, and free online resources and training programs and guidance to assist local emergency responders.

Refer to “Overview – COVID-19” in MDA for discussion of certain employee safety protocols related to COVID-19.

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, while supporting their financial, physical, and mental well-being. Tools and resources are provided to employees to help maintain and improve their health. Short- and long-term incentive plans are designed with a mix of operational and financial metrics that align employees with strategic corporate and social goals.

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You should carefully consider each of the risks described below relating to Alliant Energy, IPL and WPL, together with all of the other information contained in this combined report, before making an investment decision with respect to our securities. If any of the following risks develop into actual events, our business, financial condition or results of operations could be materially and adversely affected, and you may lose all or part of your investment.

Risks Related to Business Operations

A cyber attack may disrupt our operations or lead to a loss or misuse of confidential and proprietary information or potential liability - We operate in an industry that requires the continuous use and operation of sophisticated information technology systems and network infrastructure. We face threats from use of malicious code (such as malware, viruses and ransomware), employee theft or misuse, advanced persistent threats, vulnerabilities such as the log4j vulnerability, fraud attempts, and phishing attacks. More of our workforce is working remotely due to the novel coronavirus (COVID-19) pandemic, which has increased the number of devices connected to the internet that impact our operations and therefore increase our cyber security risk. Incidents of ransomware attacks have been increasing in frequency and magnitude, including the ransomware attack that resulted in the operator of the Colonial Pipeline paying millions of dollars in ransom to hackers as a result of a cyber attack disabling the pipeline for several days in May 2021. Cyber attacks targeting electronic control systems used at our generating facilities and for electric and gas distribution systems could result in a full or partial disruption of our electric and/or gas operations. We have relied on a global supply chain for certain components of our operating and technology systems, which may increase our exposure to cyber attacks. Any disruption of these operations could result in a loss of service to customers and a significant decrease in revenues, as well as significant expense to repair system damage and remedy security breaches. Due to the evolving nature of cyber attacks and cyber security, our current safeguards to protect our operating systems and information technology assets may not always be effective. We rely on third parties for software to protect against cyber attacks and we are at risk if such third parties are targets of cyber attacks. If the technology systems were to fail or be breached by a cyber attack or a computer virus, and not be recovered in a timely fashion, we may be unable to fulfill critical business functions and confidential data could be compromised, adversely impacting our financial condition and results of operation.

In addition, we may collect and retain sensitive information, including personal information about our customers, shareowners and employees. In some cases, we outsource administration of certain functions to vendors that could be targets of cyber attacks. For example, we outsource administration of our employee health insurance to Anthem, which was the target of a

cyber attack in 2014. Any theft, loss and/or fraudulent use of customer, shareowner, employee or proprietary data as a result of a cyber attack could subject us to significant litigation, liability and costs, as well as adversely impact our reputation with customers and regulators, among others.

Demand for energy may decrease - Our results of operations are affected by the demand for energy in our service territories. Energy demand may decrease due to many things, including proliferation of customer and third party-owned generation, technological advances that reduce the costs of renewable energy and storage solutions for our customers, loss of service territory or franchises, energy efficiency measures, technological advances that improve energy efficiency, third-party disrupters, loss of wholesale customers, the adverse impact of tariffs on our customers, and economic conditions. The loss of sales due to lower demand for energy may increase our rates for remaining customers, as our rates must cover our fixed costs. Increased customer rates may cause decreased demand for energy as customers move to customer and third party-owned generation and implement energy efficiency measures to reduce costs. The loss of customers, the inability to replace those customers with new customers, and the decrease in demand for energy could negatively impact our financial condition and results of operations.

Our strategy includes large construction projects, which are subject to risks - Our strategy includes constructing renewable generating facilities and large-scale additions and upgrades to our electric and gas distribution systems. These construction projects are subject to various risks. These risks include: the inability to obtain necessary regulatory approvals and permits in a timely manner; adverse interpretation or enforcement of permit conditions; changes in applicable laws or regulations; changes in costs of materials, equipment, commodities, fuel or labor including due to tariffs, labor issues, or supply shortages; delays caused by construction accidents or injuries; shortages in materials, equipment, inflation and qualified labor; changes to the scope or timing of the projects; general contractors, subcontractors, or equipment not performing as required under their contracts; the inability to agree to contract terms or disputes in contract terms; the inability to successfully resolve warranty claims; poor initial cost estimates; work stoppages; adverse weather conditions; government actions; legal action; unforeseen engineering or technology issues; limited access to capital or other proposed financing arrangements such as tax equity financing; and other adverse economic conditions. We may not be able to recover all costs for the projects in rates and face increased risk of potential impairment of our project investment if a construction project is not completed or is delayed, or final costs exceed expectations or the costs approved by our regulators. Inability to recover costs, or inability to complete projects in a timely manner, could adversely impact our financial condition and results of operations.

Our utility business is seasonal and may be adversely affected by the impacts of weather - Electric and gas utility businesses are seasonal businesses. Demand for electricity is greater in the summer months associated with higher air conditioning needs and winter months associated with higher heating needs. Demand for natural gas depends significantly upon temperature patterns in winter months due to heavy use in residential and commercial heating. As a result, our overall operating results in the future may fluctuate substantially on a seasonal basis. In addition, we have historically generated less revenues and income when temperatures are warmer in the winter and/or cooler in the summer. Thus, mild winters and/or summers could have an adverse impact on our financial condition and results of operations.

We face risks associated with operating electric and natural gas infrastructure - The operation of electric generation and distribution infrastructure involves many risks, including start-up risks, breakdown or failure of equipment, fires developing from our power lines, transformers or substations, dam failure at one of our hydroelectric facilities, the dependence on a specific fuel source, including the supply and transportation of fuel, the risk of performance below expected or contracted levels of output or efficiency, public and employee safety, operator error and ruptured oil and chemical tanks. The operation of our natural gas transmission and distribution infrastructure also involves many risks, such as leaks, explosions, mechanical problems, members of the public and contractors coming into contact with our infrastructure, and employee and public safety. In addition, the North American electric transmission grid is highly interconnected and, in extraordinary circumstances, disruptions at particular points within the grid could cause an extensive power outage in our service territories. Increased utilization of customer- and third party-owned generation technologies could also disrupt the reliability and balance of the electricity grid. Further, the electric transmission system in our utilities’ service territories can experience constraints, limiting the ability to transmit electricity within our service territories. The transmission constraints could result in an inability to deliver electricity from generating facilities, particularly wind generating facilities, to the national grid, or to access lower cost sources of electricity.

These risks could cause significant harm to employees, customers and the public including loss of human life, significant damage to property, adverse impacts on the environment and impairment of our operations, all of which could result in substantial financial losses to us. We are also responsible for compliance with new and changing regulatory standards involving safety, reliability and environmental compliance, including regulations under the Pipeline and Hazardous Materials Safety Administration, the Occupational Health and Safety Administration, the North American Electric Reliability Corporation and Transportation Security Authority. Failure to meet these regulatory standards could result in substantial fines. Lastly, we have obligations to provide electric and natural gas service to customers under regulatory requirements and contractual commitments. Failure to meet our service obligations could adversely impact our financial condition and results of operations.

Storms or other natural disasters may impact our operations in unpredictable ways - Storms and other natural disasters, including events such as floods, tornadoes, windstorms like the 2020 derecho in Iowa, blizzards, ice storms, extreme hot temperatures, extreme cold temperatures, fires, solar flares or pandemics may adversely impact our ability to generate,

purchase or distribute electric energy and gas or obtain fuel or other critical supplies. In addition, we could incur large costs to repair damage to our generating facilities and electric and gas infrastructure, or costs related to environmental remediation, due to storms or other natural disasters. The restoration costs may not be fully covered by insurance policies and may not be fully recovered in rates, or recovery in rates may be delayed. Storms and natural disasters may impact our customers and the resulting reduced demand for energy could cause lower sales and revenues, which may not be replaced or recovered in rates, or rate recovery may be delayed. Any of these items could adversely impact our financial condition and results of operations.

The COVID-19 pandemic and the spread of variant strains could adversely affect our business functions, financial condition, results of operations and cash flows - The ongoing COVID-19 pandemic and the spread of variant strains has resulted in widespread impacts on the economy, including disruptions to supply chains, and reduced labor availability and productivity. The COVID-19 pandemic has impacted, and may continue to impact, the economic conditions in our service territories, which may adversely impact our sales and our customers’ abilities to pay their bills. Travel and transportation restrictions and closures of commercial spaces and industrial facilities have been imposed in and across the U.S., including in the service territories in which we operate. Governmental and regulatory responses to COVID-19 have included suspending service disconnects, which may increase customer account arrears, possibly increasing our allowance for expected credit losses and decreasing our cash flows.

Closures of commercial spaces and industrial facilities, stay-at-home trends, work-from-home trends, and business disruptions have impacted sales volumes. These trends may result in a reduction in demand for electricity and natural gas from retail customers. Negative impacts on the economy resulting from the continued pandemic could adversely impact the market value of the assets that fund our pension plans, which could necessitate accelerated funding of the plans to meet minimum federal government requirements. The negative impacts on the economy, labor markets, and supply chains could also adversely impact the ability of counterparties to meet contractual payment obligations, including guarantees, or deliver contracted commodities and other goods or services at the contracted price, which could increase company expenses. Our access to the capital markets could be adversely affected by COVID-19, which could cause us to need alternative sources of funding for our operations and for working capital, any of which could increase our cost of capital.

Travel bans and restrictions, quarantines, and vaccine mandates have caused, and may continue to cause, disruptions in supply chains or access to labor that may adversely impact our planned construction projects, our ability to satisfy compliance requirements, or our operations, including our ability to maintain reliable electric and gas service. This may cause us to miss milestones on construction projects and experience operational delays, which, in the case of renewable energy projects, could delay our completion of such projects past the in-service dates required to qualify for the maximum general renewable tax credits for investments in such renewable energy projects. We have modified certain business practices to be consistent with government restrictions and best practices encouraged by government and regulatory authorities and developed risk mitigation plans for critical items and services required to continue our operations. The effects of these government restrictions could adversely impact implementation of our regulatory plans and our operations. If our workforce contracts COVID-19, it could negatively impact our operations, including our ability to maintain reliable electric and gas service.

The degree to which COVID-19 and the spread of the variant strains may impact our business operations, financial condition and results of operations is unknown at this time and will depend on future developments, including the continued spread of COVID-19 and its variants, the severity of the disease, the duration of the pandemic, possible resurgence of the disease at a later date, emergence of variants, speed, efficacy and adoption rates of vaccines, and further actions that may be taken by governmental and regulatory authorities.

Threats of terrorism and catastrophic events that could result from terrorism may impact our operations in unpredictable ways - We are subject to direct and indirect effects of terrorist threats and activities. Generation, transmission and distribution facilities, in general, have been identified as potential targets of physical or cyber attacks. Physical attacks on transmission and distribution facilities that appeared to be terrorist-style attacks have occurred. Our gas distribution system could also be the target of terrorist threats and activities. The risks posed by such attacks could include, among other things, the inability to generate, purchase or distribute electric energy or obtain fuel sources, the increased cost of security and insurance, the disruption of, volatility in, or other effects on capital markets, and a decline in the economy and/or energy usage within our service territories, all of which could adversely impact our financial condition and results of operations. In addition, the cost of repairing damage to our facilities and infrastructure caused by acts of terrorism, and the loss of revenue if such events prevent us from providing utility service to our customers, could adversely impact our financial condition and results of operations.

We may not be able to fully recover costs related to commodity prices - We have natural gas and coal supply and transportation contracts in place for some of the natural gas and coal we require to generate electricity. We also have transportation and supply agreements in place to facilitate delivery of natural gas to our customers. Our counterparties to these contracts may not fulfill their obligations to provide natural gas or coal to us due to financial or operational problems caused by natural disasters, severe weather, economic conditions, pandemics, physical attacks or cyber attacks. If we were unable to obtain enough natural gas or coal for our electric generating facilities under our existing contracts, or to obtain electricity under existing or future purchased power agreements, we could be required to purchase natural gas or coal at higher prices or forced to purchase electricity from higher-cost generating resources in the Midcontinent Independent System Operator, Inc. (MISO) energy market. We may be obligated to pay for coal deliveries under our contracts even if our coal-fired

generating facilities do not operate enough to fully utilize the amounts of coal covered by the contracts. If, for natural gas delivery to our customers, we were unable to obtain our natural gas supply requirements under existing or future natural gas supply and transportation contracts, we could be required to purchase natural gas at higher prices from other sources. Natural gas market prices have been volatile in the past and could be volatile in the future due to additional future regulations, increased demand including due to increased liquified natural gas demand from foreign countries, periods of extremely cold temperatures or disruption in supply caused by major storms or pipeline explosions. We may not be able to pass on all of the changes in costs to our customers, especially at WPL where we do not have an automatic retail electric fuel cost adjustment clause to timely recover such costs and where electric fuel cost recovery may be limited if WPL earns in excess of its authorized return on common equity. Increases in prices and costs due to disruptions that are not recovered in rates fully, in a timely manner, may adversely impact our financial condition and results of operations.

Energy industry changes could have a negative effect on our businesses - We operate in a highly regulated business environment. The advent of new and unregulated markets has the potential to significantly impact our financial condition and results of operations. Further, competitors may not be subject to the same operating, regulatory and financial requirements that we are, potentially causing a substantial competitive disadvantage for us. Changes in public policy that could be the result of a new Presidential Administration, such as new tax incentives that we cannot take advantage of or efforts to deregulate the utility industry, could provide an advantage to competitors. Changes in technology could also alter the channels through which electric customers buy or utilize power, which could reduce the revenues or increase the expenses of our utility companies. Increased competition in our primary retail electric service territories may have an adverse impact on our financial condition and results of operations.

We face risks related to non-utility operations - We rely on our non-utility operations for a portion of our earnings. If our non-utility holdings do not perform at expected levels, we could experience an adverse impact on our financial condition and results of operations.

Risks Related to Laws and Regulations

Our utility business is significantly impacted by government legislation, regulation and oversight - Our utility financial condition is influenced by how regulatory authorities, including the IUB, the PSCW and FERC, establish the rates we can charge our customers, our authorized rates of return and common equity levels, and the costs that may be recovered from customers. Our ability to timely obtain rate adjustments to earn authorized rates of return depends upon timely regulatory action under applicable statutes and regulations, and cannot be guaranteed. In future rate reviews, IPL and WPL may not receive an adequate amount of rate relief to recover all costs and earn their authorized rates of return, rates may be reduced, rate refunds may be required, rate adjustments may not be approved on a timely basis, costs may not be otherwise recovered through rates, future rates may be temporarily frozen, certain rate base items may not receive a full weighted average cost of capital, and authorized rates of return on capital may be reduced. As a result, we may experience adverse impacts on our financial condition and results of operations.

In addition, our operations are subject to extensive regulation primarily by the IUB, the PSCW and FERC. We are also subject to oversight and monitoring by organizations such as the North American Electric Reliability Corporation, the Midwest Reliability Organization, the Pipeline and Hazardous Materials Safety Administration, MISO and the Transportation Security Administration. The impacts on our operations include: our ability to site and construct new generating facilities, such as renewable energy projects, and recover associated costs, including our ability to continue to use a renewable energy rider in Iowa; our ability to decommission generating facilities and recover related costs and the remaining carrying value of these facilities and related assets; possible changes to MISO’s methodology establishing capacity planning reserve margin requirements that may impact how and when new generating facilities such as IPL’s and WPL’s additional solar and wind generation may be accredited with energy capacity and may require IPL and WPL to adjust their current resource plans, the need to add additional resources to comply with MISO’s proposal, or procure capacity in the market whereby such costs might not be recovered in rates; the impact of the lack of availability of existing and new generating facilities has on our accredited capacity for such facilities pursuant to MISO’s methodology for establishing capacity planning reserve margin requirements; the rates paid to transmission operators and how those costs are recovered from customers, including our ability to continue to use a transmission rider in Iowa; our ability to site, construct and recover costs for new natural gas pipelines; our ability to recover costs to upgrade our electric and gas distribution systems; the amount of certain sources of energy we must use, such as renewable sources; our ability to purchase generating facilities and recover the costs associated therewith; our ability to sell utility assets and any conditions placed upon the sale of such assets; our ability to enter into purchased power agreements and recover the costs associated therewith; the allocation of expenditures by transmission companies on transmission network upgrades and our ability to recover costs associated therewith; reliability; safety; the issuance of securities and ability to use other financing arrangements, such as tax equity financing to finance renewable energy projects; accounting matters; and transactions between affiliates. These regulatory authorities and organizations are also empowered to impose financial penalties and other sanctions, including requirements to implement new compliance programs. Failure to obtain approvals for any of these matters in a timely manner, or receipt of approvals with uneconomical conditions, may cause us not to pursue the construction of such projects or to record an impairment of our assets and may have a material adverse impact on our financial condition and results of operations. Changes to these regulations could materially increase our costs or cause us to reconsider our strategy, which could have a material adverse impact on our financial condition and results of operations.

Provisions of the Wisconsin Utility Holding Company Act may limit our ability to invest in or grow our non-utility activities and may deter potential purchasers who might be willing to pay a premium for our stock.

Changes to certain tax elections, tax regulations and future taxable income could negatively impact our financial condition and results of operations - We have significantly reduced our federal and state income tax obligations through tax planning strategies and the utilization of bonus depreciation deductions for certain expenditures for property. These tax planning strategies and bonus depreciation deductions have generated large taxable losses and tax credits that have resulted in significant federal and state net operating losses and tax credit carryforwards. We plan to utilize substantially all of these net operating losses and tax credit carryforwards in the future to reduce our income tax obligations. If we cannot generate enough taxable income in the future to utilize all of the net operating losses and tax credit carryforwards before they expire due to lower than expected financial performance or changes to tax regulations, we may incur material charges to earnings. In addition, our tax liability is determined by our taxable income multiplied by the current tax rates in effect. If the tax rates are increased or a minimum corporate income tax is implemented, as has been proposed by the current Presidential Administration, we may experience adverse impacts to our financial condition and results of operations.

Our utility business currently operates wind generating facilities, which generate production tax credits for us to use to reduce our federal tax obligations. The amount of production tax credits we earn is dependent on the date the qualifying generating facilities are placed in service, the level of electricity output generated by our qualifying generating facilities and the applicable tax credit rate. If there is a disagreement on the in-service date, the amount of production tax credits that we can generate may be significantly reduced. A variety of operating and economic parameters, including transmission constraints, the imbalance of supply and demand of wind energy resulting in unfavorable pricing for wind energy, adverse weather conditions and breakdown or failure of equipment, could significantly reduce the production tax credits generated by our wind farms resulting in a material adverse impact on our financial condition and results of operations. Our strategic plan includes developing solar generating facilities, which are expected to generate investment tax credits. Investment tax credits are dependent on the date the qualifying generating facilities begin and end construction and the costs of the qualifying generating facilities. If there is a disagreement on the dates construction began and ended or the qualifying costs, the amount of investment tax credits awarded may be significantly reduced, possibly adversely impacting our financial condition and results of operations.

Our utility businesses are subject to numerous environmental laws and regulations - Our utilities are subject to numerous federal, regional, state and local environmental laws, regulations, court orders, and international treaties. These laws, regulations and court orders generally concern emissions into the air, discharges into water, use of water, wetlands preservation, remediation of contamination, waste disposal and containment, disposal of coal combustion residuals, hazardous waste disposal, threatened and endangered species, and noise regulation, among others. Failure to comply with such laws, regulations and court orders, or to obtain or comply with any necessary environmental permits pursuant to such laws and regulations, could result in injunctions, fines or other sanctions. Environmental laws and regulations affecting power generation and electric and gas distribution are complex and subject to continued uncertainty and could be changed by the current Presidential Administration. These laws and regulations have imposed, and proposed laws and regulations could impose in the future, additional costs on our utility operations. We have incurred, and will continue to incur, capital and other expenditures to comply with these and other environmental laws and regulations. Changes in or new development of environmental restrictions may force us to incur significant expenses or expenses that may exceed our estimates. There can be no assurance that we would be able to recover all or any increased environmental costs from our customers. Failure to comply with the laws, regulations and court orders, changes in the laws and regulations and failure to recover costs of compliance may adversely impact our financial condition and results of operations.

Actions related to global climate change and reducing greenhouse gas (GHG) emissions could negatively impact us - Regulators, customers and investors continue to raise concerns about climate change and GHG emissions. National regulatory action and international regulatory actions continue to evolve. We are focused on executing a long-term strategy to deliver reliable and affordable energy with lower carbon dioxide (CO2) emissions independent of changing policies and political landscape. However, it is unclear how these climate change concerns will ultimately impact us. We could incur costs or other obligations to comply with future GHG regulations, and could become the target of legal claims or challenges, because generating electricity using fossil fuels emits CO2 and other GHGs. Further, investors may determine that we are too reliant on fossil fuels, reducing demand for our stock, which may cause our stock price to decrease, or not buy our debt securities, which may cause our cost of capital to increase. We could face additional pressures from customers, investors or other stakeholders to more rapidly reduce CO2 emissions on a voluntary-basis, including faster adoption of lower CO2 emitting technologies and management of excess renewable energy credits. The timing and pace to fully achieve decarbonization is also contingent on the future development of technologies to reliably store and manage electricity, as well as electrification of other economic sectors. The EPA’s approach and timing for implementing rules to regulate CO2 emissions at fossil-fuel fired electric generating units remains undecided and subject to litigation and could change in the current Presidential Administration. Various legislative and regulatory proposals to address climate change at the national, state and local levels continue to be introduced. Potential future requirements to reduce CO2, methane and other GHGs from the energy and manufacturing sectors could affect our operations in various ways. Regulation or legislation mandating CO2 emissions reductions or other clean energy standards affecting utility companies could materially increase costs, causing some electric generating units to be uneconomical to operate or maintain. We are vulnerable to potential risks associated with transition to a lower-carbon economy that may extend to our supply chain and natural gas operations. Regulation of oil and gas production

could affect our upstream supply of natural gas for electricity generation and to provide directly to our residential and business customers from our local distribution company. This could result in rapid increased demand for alternative non-fossil energy sources and economy-wide electrification. Changes to regional and local climate trends such as the frequency, seasonality, and severity of weather conditions could directly and indirectly impact our company. Acute and chronic physical risks could disrupt our operations or affect our property. Furthermore, it could affect the timing of peak demand and overall energy consumption of our customers. We cannot provide any assurance regarding the potential impacts of climate change or related policies and regulations to reduce GHG emissions on our operations and these could have a material adverse impact on our financial condition and results of operations.

Risks Related to Economic, Financial and Labor Market Conditions

We are subject to employee workforce factors that could affect our businesses - We operate in an industry that requires specialized technical skills. Further, we must build a workforce that is innovative, customer-focused and competitive to thrive in the future in order to successfully implement our strategy. It may be difficult to hire and retain such a skilled workforce due to labor market conditions, such as low unemployment rates in our service territories, the length of time employees need to acquire the skills, and general competition for talent. We are also subject to collective bargaining agreements covering approximately 1,800 employees. Any work stoppage experienced in connection with negotiations of collective bargaining agreements could adversely affect our financial condition and results of operations as well as our ability to implement our strategy.

We are subject to limitations on our ability to pay dividends - Alliant Energy is a holding company with no significant operations of its own. The primary sources of funds for Alliant Energy to pay dividends to its shareowners are dividends and distributions from its subsidiaries, primarily its utility subsidiaries. Our subsidiaries are separate and distinct legal entities and have no obligation to pay any amounts to Alliant Energy, whether by dividends, distributions, loans or other payments. The ability of our subsidiaries to pay dividends or make distributions to Alliant Energy and, accordingly, our ability to pay dividends on Alliant Energy common stock will depend on regulatory limitations, earnings, cash flows, capital requirements and general financial condition of our subsidiaries. Our utilities have dividend payment restrictions based on the terms of regulatory limitations applicable to them. If we do not receive adequate dividends and distributions from our subsidiaries, then we may not be able to make, or may have to reduce, dividend payments on Alliant Energy common stock.

We may incur material post-closing adjustments related to past asset and business divestitures - We have sold certain non-utility subsidiaries such as Whiting Petroleum Corporation (Whiting Petroleum). We may continue to incur liabilities relating to our previous ownership of, or the transactions pursuant to which we disposed of, these subsidiaries and assets. Any potential liability depends on a number of factors outside of our control, including the financial condition of Whiting Petroleum, certain of its partners, and/or their assignees. Any required payments on retained liabilities, guarantees or indemnification obligations with respect to Whiting Petroleum or other past and future asset or business divestitures could adversely impact our financial condition and results of operations.

We are dependent on the capital markets and could be negatively impacted by disruptions in the capital markets - Successful implementation of our strategy is dependent upon our ability to access the capital markets. We have forecasted capital expenditures of approximately $7 billion over the next four years. Disruption, uncertainty or volatility in the capital markets could increase our cost of capital or limit our ability to raise funds needed to operate our businesses. Disruptions could be caused by Federal Reserve policies and actions, currency concerns, inflation, economic downturn or uncertainty, monetary policies, a negative view of the utility industry or our company, failures of financial institutions, U.S. debt management concerns, U.S. debt limit and budget debates, including government shutdowns, European and worldwide sovereign debt concerns, other global or geopolitical events, or other factors. Increases in interest rates may cause the price of our equity securities to decline. Any disruptions in capital markets could adversely impact our ability to implement our strategy.

We rely on our strong credit ratings to access the credit markets. If our credit ratings are downgraded for any reason, such as worsening credit metric impacts, negative changes to our regulatory environment, or general negative outlook for the utility industry, we could pay higher interest rates in future financings, the pool of potential lenders could be reduced, borrowing costs under existing credit facilities could increase, our access to the commercial paper market could be limited, or we could be required to provide additional credit assurance, including cash collateral, to contract counterparties. If our access to capital were to become significantly constrained or costs of capital increased significantly due to lowered credit ratings, prevailing industry conditions, regulatory constraints, volatility of the capital markets, inflation or other factors, our financial condition and results of operations could be adversely affected.

Our pension and other postretirement benefits plans are subject to investment and interest rate risk that could negatively impact our financial condition - We have pension and other postretirement benefits plans that provide benefits to many of our employees and retirees. Costs of providing benefits and related funding requirements of these plans are subject to changes in the liabilities of the plans and market value of the assets that fund the plans. The funded status of the plans and the related costs reflected in our financial statements are affected by various factors, which are subject to an inherent degree of uncertainty, including economic conditions, financial market performance, interest rates, life expectancies and demographics. Recessions and volatility in the domestic and international financial markets have negatively affected the asset values of our pension plans at various times in the past. Poor investment returns or lower interest rates may necessitate

accelerated funding of the plans to meet minimum federal government requirements, which could have an adverse impact on our financial condition and results of operations.

None.

Alliant Energy - As a holding company, Alliant Energy doesn’t directly own any significant properties other than the stock of its subsidiaries. The principal properties of those subsidiaries are as follows:

IPL and WPL

Electric - At December 31, 2021, IPL’s and WPL’s facilities by primary fuel type were as follows:

(a)Based on the accredited generating capacity of the EGUs as of December 31, 2021 included in MISO’s resource adequacy process for the planning period from June 2021 through May 2022. IPL’s Battery Storage did not receive any accredited generating capacity for the planning period from June 2021 through May 2022. Electricity generated from the West Riverside Solar Garden is used to offset electricity usage at the West Riverside Energy Center and does not receive any accredited generating capacity.

(b)Represents IPL’s 48% ownership interest in this 726 MW (nameplate capacity) / 656 MW (generating capacity) EGU, which is operated by IPL.

(c)Represents IPL’s 25.695% ownership interest in this 696 MW (nameplate capacity) / 610 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(d)Represents IPL’s 28% ownership interest in this 584 MW (nameplate capacity) / 501 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(e)Represents IPL’s 4% ownership interest in this 812 MW (nameplate capacity) / 708 MW (generating capacity) EGU, which is operated by MidAmerican Energy Company.

(f)Represents WPL’s 91% ownership interest in this 723 MW (nameplate capacity) / 654 MW (generating capacity) EGU, which is operated by WPL.

(g)Represents Units 2 and 3, which WPL owns. WPL also operates, but does not own, South Fond du Lac Combustion Turbines Units 1 and 4.

(h)Represents WPL’s 42.64% ownership interest in this 138 MW (nameplate capacity) / 17 MW (generating capacity) EGU, which is operated by Invenergy Services, LLC.

(i)Represents WPL’s 53.5% ownership interest in this 1,112 MW (nameplate capacity) / 1,093 MW (generating capacity) EGU, which is operated by WPL.

(j)Represents WPL’s 91% ownership interest in this 4 MW (nameplate capacity) EGU, which is operated by WPL.

IPL and WPL own overhead electric distribution line, underground electric distribution cable and substation distribution transformers, substantially all of which are located in Iowa for IPL and Wisconsin for WPL.

Gas - IPL’s and WPL’s gas properties consist primarily of mains and services, meters, regulating and gate stations and other related transmission and distribution equipment. IPL’s and WPL’s gas distribution facilities include gas mains located in Iowa and Wisconsin, respectively.

Other - IPL’s other property includes steam service assets. Refer to Note 10 for information regarding WPL’s lease of the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business.

Corporate Services - Corporate Services’ property included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2021 consisted primarily of a customer billing and information system for IPL and WPL and other computer software, and the corporate headquarters building located in Madison, Wisconsin.

AEF - AEF’s principal properties included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2021 were as follows:

Non-utility Generation - Includes the Sheboygan Falls Energy Facility, a 347 MW, simple-cycle, natural gas-fired facility near Sheboygan Falls, Wisconsin that was placed in service in 2005 and is leased to WPL. The Sheboygan Falls Energy Facility was accredited with 295 MW of generating capacity for MISO’s resource adequacy process for the planning period from June 2021 through May 2022.

Travero - Includes a short-line rail freight service in Iowa; a Mississippi River barge, rail and truck freight terminal in Illinois; freight brokerage services; and a rail-served warehouse in Iowa, which began operations in 2021.

None. SEC regulations require Alliant Energy, IPL and WPL to disclose information about certain proceedings arising under federal, state or local environmental provisions when a governmental authority is a party to the proceedings and such proceedings involve potential monetary sanctions that Alliant Energy, IPL and WPL reasonably believe will exceed a specified threshold. Pursuant to the SEC regulations, Alliant Energy, IPL and WPL use a threshold of $1 million for purposes of determining whether disclosure of any such proceedings is required. Applying this threshold, there are no environmental matters to disclose for this period. Refer to Note 17(c) for discussion of legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business.

None.

INFORMATION ABOUT EXECUTIVE OFFICERS

The executive officers of Alliant Energy, IPL and WPL for which information must be included are the same; however, different positions may be held at the various registrants. None of the executive officers for Alliant Energy, IPL or WPL listed below are related to any member of the Board of Directors or nominee for director or any other executive officer. All of the executive officers have no definite terms of office and serve at the pleasure of the Board of Directors. The executive officers of Alliant Energy, IPL and WPL as of the date of this filing are as follows:

PART II

Common Stock Data - Alliant Energy’s common stock trades on the Nasdaq Global Select Market under the symbol “LNT,” and the closing sales price at December 31, 2021 was $61.47.

Shareowners - At December 31, 2021, there were 22,334 holders of record of Alliant Energy’s common stock, including holders through Alliant Energy’s Shareowner Direct Plan. Alliant Energy is the sole common shareowner of all 13,370,788 and 13,236,601 shares of IPL and WPL common stock, respectively, currently outstanding. As a result, there is no established public trading market for the common stock of either IPL or WPL.

Dividends - In November 2021, Alliant Energy announced an increase in its targeted 2022 annual common stock dividend to $1.71 per share, which is equivalent to a quarterly rate of $0.4275 per share, beginning with the February 2022 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.

Common Stock Repurchases - A summary of Alliant Energy common stock repurchases for the quarter ended December 31, 2021 was as follows:

(a)All shares were purchased on the open market and held in a rabbi trust under the DCP. There is no limit on the number of shares of Alliant Energy common stock that may be held under the DCP, which currently does not have an expiration date.

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 2021 compared to 2020. Refer to MDA in the combined 2020 Form 10-K for details on certain financial information for 2020 compared to 2019.

OVERVIEW

Strategy and Mission

Alliant Energy’s mission is to deliver affordable energy solutions and exceptional service that its customers and communities count on - safely, efficiently, reliably and responsibly. The mission is supported by a strategy focused on meeting the evolving expectations of customers while providing an attractive return for investors, as well as serving its customers and building strong communities. 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 Blueprints, also known as its cleaner energy strategy, is expected to result in cost savings for its utility customers through the planned transition away from coal-fired EGUs and incorporation of additional renewable energy, renewable tax credits for investments in renewable energy projects, and utilization of renewable project tax equity financing under the current tax regulations.

• WPL maintaining flat base rates in 2021 by utilizing Federal Tax Reform benefits and expected lower fuel costs to offset higher revenue requirements from rate base additions.

• 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.

• 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 as a result of expansion of renewable generation and shortening the term of IPL’s DAEC PPA by 5 years.

• Issuance of new long-term debt in 2021 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).

• 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 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 cleaner 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’ 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 and 2023, approximately 400 MW of solar generation at IPL with in-service dates in 2023 and 2024 and approximately 75 MW of battery storage in 2024 at IPL. 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.

• IPL’s December 2021 completion of the fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas.

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 -

• WPL entered into a new wholesale power supply agreement, which was effective January 1, 2021 and brought approximately 55 MW of load to WPL’s electric system in 2021.

• 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.

COVID-19

The outbreak of COVID-19 has become a global pandemic and Alliant Energy’s service territories are not immune to the challenges presented by COVID-19. Despite these challenges, Alliant Energy, IPL and WPL continue to focus on providing the critical, reliable service their customers depend on, while emphasizing the health and welfare of their employees, customers and communities. Alliant Energy, IPL and WPL have not experienced significant impacts on their overall business operations, financial condition, results of operations or cash flows; however, the degree to which the COVID-19 pandemic may impact such items in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities. Alliant Energy has mitigated the impact of any sales declines from COVID-19 by accelerating planned cost transformation activities. Actual and potential impacts from COVID-19 include, but are not limited to, the following:

Operational and Supply Chain Impacts - Alliant Energy has modified certain business practices to help ensure the health and safety of its employees, contractors, customers and vendors consistent with orders and best practices issued by government and regulatory authorities. For example, Alliant Energy implemented its business continuity and pandemic plans for critical items and services, including travel restrictions, physical distancing, working-from-home protocols, and rescheduling of planned EGU outages. Alliant Energy also temporarily suspended service disconnects, waived late payment fees for its customers, and modified reconnect service procedures to ensure continuity of service for customers unable to pay their bills and consistency with regulatory orders.

While Alliant Energy has not experienced any significant issues to-date, it continues to monitor potential disruptions or constraints in materials and supplies from key suppliers. Alliant Energy’s construction projects are currently progressing as planned with added safety protocols, and while

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Quantitative and Qualitative Disclosures About Market Risk are reported in “Other Matters - Market Risk Sensitive Instruments and Positions” in MDA.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowners and the Board of Directors of Alliant Energy Corporation:

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, 2021 and 2020, the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, 2021, and the related notes and the schedules listed in the Index at Item 15 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 18, 2022, expressed an unqualified opinion on the Company’s internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Regulatory Assets and Regulatory Liabilities - Impact of rate regulation on the financial statements - Refer to Notes 1 and 2 to the financial statements

Critical Audit Matter Description

Alliant Energy Corporation, through its wholly-owned subsidiaries Interstate Power and Light Company and Wisconsin Power and Light Company, is subject to rate regulation by the Federal Energy Regulatory Commission and the respective state commissions in Iowa and Wisconsin (collectively the “regulatory agencies”). Management has determined it meets the requirements under accounting principles generally accepted in the United States of America to prepare its financial statements applying the Regulated Operations Topic 980 of the Financial Accounting Standards Board’s Accounting Standards Codification. As of December 31, 2021, the Company had a recorded consolidated regulatory assets balance of $1,940 million and regulatory liabilities balance of $1,271 million.

The Company’s rates are subject to regulatory rate-setting processes and periodic earnings oversight. The regulation of rates is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital. Regulatory assets represent incurred costs that have been deferred and are probable of recovery in future customer rates. Regulatory liabilities represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred. The Company’s regulatory assets and regulatory liabilities are recognized in accordance with the rulings of the regulatory agencies. A change in these rulings may result in a material impact on results of operations and the amount of assets and liabilities in the financial statements. Future regulatory rulings may impact the carrying value and accounting treatment of the regulatory assets and regulatory liabilities.

We identified the impact of rate regulation as a critical audit matter due to the significant judgments made by management to support its assertions about impacted account balances and disclosures and the high degree of subjectivity involved in assessing the impact of future regulatory orders on the financial statements. Management judgments include assessing the likelihood of the recovery of incurred costs and refund of obligations to customers in future rates. Given that management’s accounting judgments are based on assumptions about the outcome of future decisions by the regulatory agencies, auditing these judgments required specialized knowledge of accounting for rate regulation and the rate-setting process due to its inherent complexities.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the regulatory filings by management and the uncertainty of future decisions by the regulatory agencies included the following, among others:

• We tested the design and operating effectiveness of management’s controls over the evaluation of regulatory assets and liabilities, including the monitoring and evaluation of regulatory developments that may affect the likelihood of recovering costs in future rates or of a future reduction in rates.

• We obtained and evaluated the Company’s analysis supporting the probability of recovery for regulatory assets or refund or future reduction in rates for regulatory liabilities not yet addressed in a regulatory order to assess the reasonability of management’s assertions.

• We inquired of management regarding current events impacting the Company and inspected minutes of the board of directors and other committees of the Company and evaluated whether matters were identified that may have an impact on recorded regulatory asset and liability balances.

• We read relevant regulatory orders, regulatory statutes, interpretations, procedural memorandums, filings made by interveners, and other publicly available information issued by the regulatory agencies that pertain to the Company as well as to other relevant public utilities. We evaluated the external information and assessed whether there were matters in such information that would be contradictory to the assessment of recovery of the Company’s regulatory assets or refund of regu

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Alliant Energy’s, IPL’s and WPL’s management evaluated, with the participation of each of Alliant Energy’s, IPL’s and WPL’s Chief Executive Officer, Chief Financial Officer and Disclosure Committee, the effectiveness of the design and operation of Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures as of the end of the quarter ended December 31, 2021 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive Officer and the Chief Financial Officer concluded that Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures were effective as of the end of the quarter ended December 31, 2021.

There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended December 31, 2021 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting.

Management’s Annual Report on Internal Control over Financial Reporting - The management of Alliant Energy, IPL and WPL are responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Securities Exchange Act of 1934. Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP.

Because of the inherent limitations of internal control over financial reporting, misstatements may not be prevented or detected on a timely basis. Also, projections of any evaluation of the effectiveness of the internal control over financial reporting to future periods are subject to the risk that the controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Alliant Energy’s, IPL’s and WPL’s management assessed the effectiveness of their respective internal control over financial reporting as of December 31, 2021 using the criteria set forth in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on these assessments, Alliant Energy’s, IPL’s and WPL’s management concluded that, as of December 31, 2021, their respective internal control over financial reporting was effective.

Deloitte & Touche LLP, Alliant Energy’s independent registered public accounting firm, has audited Alliant Energy’s internal control over financial reporting. That report is included herein. This report does not include an attestation report of IPL’s and WPL’s independent registered public accounting firm regarding its assessment of IPL’s and WPL’s internal control over financial reporting.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Shareowners and the Board of Directors of Alliant Energy Corporation:

Opinion on Internal Control over Financial Reporting

We have audited the internal control over financial reporting of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control - Integrated Framework (2013) issued by COSO.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated financial statements as of and for the year ended December 31, 2021, of the Company and our report dated February 18, 2022, expressed an unqualified opinion on those financial statements.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/ DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

February 18, 2022

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PART III

The directors of Alliant Energy, IPL and WPL are the same, and therefore, the information required by Item 10 relating to directors and nominees for election of directors is the same for all registrants. The information required by Item 10 relating to directors and nominees for election of directors at the 2022 Annual Meeting of Shareowners, the timely filing of reports under Section 16 of the Securities Exchange Act of 1934, audit committees and audit committee financial experts, and Alliant Energy’s, IPL’s and WPL’s Code of Conduct is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years. The code of ethics, also referred to as the Code of Conduct, of Alliant Energy, IPL and WPL are the same. Information regarding executive officers of Alliant Energy, IPL and WPL may be found in Part I of this report under the caption “Information About Executive Officers.”

The directors and executive officers of Alliant Energy, IPL and WPL for which compensation information must be included are the same. Therefore, the information required by Item 11 for each of Alliant Energy, IPL and WPL is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years.

Information regarding Alliant Energy’s equity compensation plans as of December 31, 2021 was as follows:

(a)Represents performance shares, performance restricted stock units and restricted stock units granted under the 2020 OIP. Performance restricted stock units and performance shares are paid out in shares of Alliant Energy’s common stock. The performance share and performance restricted stock unit awards are adjusted by a performance multiplier, which ranges from zero to 200%, based on the performance criteria. The performance share and performance restricted stock unit awards included in column (A) of the table reflect an assumed payout in the form of Alliant Energy’s common stock at the maximum performance multiplier of 200%. Also included are restricted stock units granted under the 2020 OIP, which are paid out in shares of Alliant Energy’s common stock at the expiration of a three-year time-vesting period.

(b)All of the available shares under the 2020 OIP may be issued as awards in the form of shares of Alliant Energy’s common stock, restricted stock, restricted stock units, performance shares, performance units and other stock-based or cash-based awards. As of December 31, 2021, there were performance shares and restricted stock units (performance- and time-vesting) outstanding under the 2020 OIP.

(c)As of December 31, 2021, there were 383,532 shares of Alliant Energy’s common stock held under the DCP, which is described in Note 13(c).

(d)There is no limit on the number of shares of Alliant Energy’s common stock that may be held under the DCP.

The remainder of the information required by Item 12 for Alliant Energy, and the information required by Item 12 for each of IPL and WPL, is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal year.

The information required by Item 13 for each of Alliant Energy, IPL and WPL is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s, IPL’s and WPL’s fiscal years.

ALLIANT ENERGY

The information required by Item 14 is incorporated herein by reference to the relevant information in the 2022 Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s fiscal year.

IPL AND WPL

Each of IPL’s and WPL’s Audit Committee of the Board of Directors has adopted a policy that requires advance approval of all audit, audit-related, tax and other permitted services performed by the independent registered public accounting firm. The policy provides for pre-approval by the Audit Committee of specifically defined audit and non-audit services after the Audit Committee is provided with the appropriate level of details regarding the specific services to be provided. The policy does not permit delegation of the Audit Committee’s authority to management. In the event the need for specific services arises between Audit Committee meetings, the Audit Committee has delegated to the Chairperson of the Audit Committee authority to approve permitted services provided that the Chairperson reports any decisions to the Audit Committee at its next scheduled meeting. The principal accounting fees billed to Alliant Energy by its independent registered public accounting firm, all of which were approved in advance by the Audit Committee, directly related and allocated to IPL and WPL were as follows (in thousands):

IPL’s and WPL’s audit fees for 2021 and 2020 consisted of the respective fees billed for the audits of the financial statements of IPL and its subsidiaries and WPL and its subsidiary, for reviews of financial statements included in Form 10-Q filings, and for services normally provided in connection with statutory and regulatory filings, such as financing transactions. IPL’s and WPL’s audit fees also included their respective portion of fees for the 2021 and 2020 audits of Alliant Energy’s financial statements and effectiveness of internal controls over financial reporting. IPL’s and WPL’s audit-related fees for 2021 and 2020 consisted of the fees billed for services rendered related to employee benefits plan audits and other attest services. IPL’s and WPL’s tax fees for 2021 and 2020 consisted of the fees billed for professional services rendered for tax compliance, tax advice and tax planning, including all services performed by the tax professional staff of affiliates of the independent registered public accounting firm, except those rendered in connection with the audit. All other fees for 2021 and 2020 for IPL and WPL consisted of license fees for accounting research software products and virtual seminars. The Audit Committee does not consider the provision of non-audit services by the independent registered public accounting firm described above to be incompatible with maintaining independence of the independent registered public accounting firm.

PART IV

(1)Consolidated Financial Statements - Refer to Item 8 Financial Statements and Supplementary Data for Alliant Energy’s, IPL’s and WPL’s financial statements and Reports of Independent Registered Public Accounting Firm (Public Company Accounting Oversight Board ID No. 34).

(2)Financial Statement Schedules -

SCHEDULE I - CONDENSED PARENT COMPANY FINANCIAL STATEMENTS

Refer to accompanying Notes to Condensed Financial Statements.

Refer to accompanying Notes to Condensed Financial Statements.

Refer to accompanying Notes to Condensed Financial Statements.

ALLIANT ENERGY CORPORATION (Parent Company Only)

NOTES TO CONDENSED FINANCIAL STATEMENTS

Pursuant to rules and regulations of the SEC, the Condensed Financial Statements of Alliant Energy Corporation (Parent Company Only) do not reflect all of the information and notes normally included with financial statements prepared in accordance with GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the Financial Statements and related Notes included in the combined 2021 Form 10-K, Part II, Item 8, which is incorporated herein by reference.

In the Condensed Financial Statements of Alliant Energy Corporation (Parent Company Only), investments in subsidiaries are accounted for using the equity method.

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

Valuation and Qualifying Accounts Which are Deducted in the Balance Sheet from the Assets to Which They Apply:

Note: The above provisions relate to various customer, notes and other receivable balances included in various line items on the respective balance sheets.

(a)Accumulated provision for uncollectible accounts: In accordance with its regulatory treatment, certain amounts provided by WPL are recorded in regulatory assets.

(b)Deductions are of the nature for which the reserves were created. In the case of the accumulated provision for uncollectible accounts, deductions from this reserve are reduced by recoveries of amounts previously written off.

(c)Refer to Note 5(b) for discussion of IPL’s sales of accounts receivable program.

NOTE: All other schedules are omitted because they are not applicable or not required, or because that required information is shown either in the financial statements or in the notes thereto.

(3) Exhibits Required by SEC Regulation S-K - Pursuant to Item 601(b)(4)(iii) of Regulation S-K, the registrants agree to furnish to the SEC, upon request, any instrument defining the rights of holders of unregistered long-term debt not filed as an exhibit to this combined Form 10-K. No such instrument authorizes securities in excess of 10% of the total assets of Alliant Energy, IPL or WPL, as the case may be. The following exhibits for Alliant Energy, IPL and WPL are filed herewith or incorporated herein by reference.