Alliant Energy (LNT) 10-K risk factor changes: FY2024 vs FY2023

We face threats from use of malicious code (such as malware, viruses and ransomware), employee theft or misuse, [removed: advanced persistent threats,] vulnerabilities (such as the log4j and MOVEit vulnerabilities), fraud attempts, [removed: and] phishing [removed: attacks.][added: attacks and advanced persistent threats.]

In addition, we use information technology systems to collect and retain sensitive information, including personal information about our customers, shareowners and [removed: employees.][added: employees, which is subject to privacy laws and regulations.]

[removed: Energy demand may decrease due to many things, including economic conditions, proliferation of customer and third party-owned] [added: owned] generation, technological advances that reduce the costs of renewable energy and [added: energy] storage solutions for our customers, government policies, such as the Inflation Reduction Act of [removed: 2022 (IRA Act),] [added: 2022,] which incentivize customer and third party-owned generation, loss of service territory or franchises, energy efficiency measures, [added: changes in customer usage due to rate design changes, such as time of use rates,] technological advances that improve energy efficiency, third-party disrupters, loss of wholesale customers, loss of customers that pursue their own renewable projects to achieve specific sustainability goals, and the adverse impact of tariffs on our customers.

Our strategy includes large construction projects, which are subject to risks - Our strategy includes constructing renewable generating facilities, energy storage facilities, natural gas-fired generating [removed: facilities] [added: facilities,] and large-scale additions and upgrades to our electric and gas distribution systems and generating assets.

These construction [added: and upgrade] projects are subject to various risks.

[removed: These risks include: the inability to obtain necessary regulatory approvals and permits in a timely] manner; adverse interpretation or enforcement of permit conditions; changes in applicable laws or regulations; changes in costs of materials, equipment, commodities, fuel or labor including due to inflation, [removed: tariffs, labor issues,] [added: tariffs] or [removed: supply shortages;] [added: labor issues;] delays caused by construction accidents or injuries; shortages in materials, equipment, or qualified labor; changes to the scope or timing of the projects; general contractors, subcontractors, or equipment not performing as required under their contracts; the inability to agree to contract terms or disputes in contract terms; the inability to successfully resolve warranty claims; poor initial cost estimates; work stoppages; adverse weather conditions; government actions; legal action; unforeseen engineering or technology issues; limited access to capital or other financing arrangements; and other adverse economic conditions.

We may not be able to meet capacity [removed: requirements] [added: requirements, including new demand from high usage customers,] to comply with electric demand planning reserve margins if a construction project is not completed or is delayed.

The global supply chain has experienced, and is expected to continue to experience, disruptions due to a multitude of factors, such as geopolitical issues, supplier manufacturing constraints, labor issues, transportation issues, [added: tariffs, changes in laws, executive orders,] resource availability, long lead times, [removed: tariffs,] tighter credit markets, inflation, pandemics and weather.

We face risks associated with operating electric and natural gas infrastructure - The operation of electric generation and distribution infrastructure involves many risks, including start-up risks, breakdown or failure of equipment, fires developing from our power lines, transformers, energy storage facilities, or substations, dam failure at one of our hydroelectric facilities, the dependence on a specific fuel source, including the supply and transportation of fuel, the risk of performance below expected or contracted levels of output or efficiency, members of the public or contractors coming into contact with our infrastructure, public and employee safety, operator [removed: error] [added: error,] and ruptured oil and chemical tanks.

The operation of our natural gas distribution and transportation infrastructure also involves many risks, such as leaks, explosions, mechanical problems, members of the [added: public or contractors coming into contact with our infrastructure, and employee and public safety.]

Further, the electric transmission system in our utilities’ service territories can experience constraints, limiting [removed: the] [added: our] ability to transmit [removed: electricity within our service territories.][added: electricity.]

Failure to meet our service [removed: obligations, and failure of IPL’s solar generating facilities to achieve a certain level of output,] [added: obligations] could adversely impact our financial condition and results of operations.

Storms and natural disasters may impact our customers and the resulting reduced demand for energy could cause [removed: lower sales and revenues, which may not be replaced or recovered in rates, or rate recovery may be delayed.]

If we were unable to obtain enough natural gas or coal for our electric generating [removed: facilities] [added: units] under our existing contracts, or to obtain electricity under existing or future purchased power agreements, we could be required to purchase natural gas or coal at higher prices, need to secure higher cost delivery of natural gas or coal, be forced to curtail the operation of our natural gas-fired or coal-fired generating facilities, be forced to purchase electricity from higher-cost generating resources in the [removed: Midcontinent Independent System Operator, Inc. (MISO)] [added: MISO] energy market and/or be required to purchase replacement capacity to comply with electric demand planning reserve margins.

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 [added: 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.]

Our utility business is significantly impacted by government legislation, regulation and oversight \- Our utility financial condition is influenced by how regulatory authorities, including the [removed: IUB,] [added: IUC,] the PSCW and FERC, establish the rates we can charge our customers, our authorized rates of return and common equity levels, and the costs that may be recovered from customers.

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, [removed: future] [added: earnings above certain thresholds may be required to be refunded, recovery of capital expenditures, including those for electric distribution systems, above certain thresholds may be capped or not be allowed,] rates may be temporarily frozen, [removed: laws or] [added: such as IPL’s current retail electric rate base moratorium through September 2029, laws,] rules [added: or settlements] may limit the ability to file rate adjustments or the period covered by a rate adjustment, regulatory decisions may limit the ability to defer recovery of and a return on prudently incurred costs in between rate reviews, certain rate base items may not receive a full weighted average cost of capital, and authorized rates of return on capital may be reduced.

In addition, our operations are subject to extensive regulation primarily by the [removed: IUB,] [added: IUC,] the PSCW and FERC.

We are also subject to oversight and monitoring by organizations such as the North American Electric Reliability Corporation, the Midwest Reliability Organization, the Pipeline and Hazardous Materials Safety Administration, [removed: MISO] [added: the Midcontinent Independent System Operator, Inc. (MISO)] and the Department of Homeland Security Transportation Security Administration.

[removed: The impacts on our operations include: our ability to site] and [removed: construct new energy facilities, such as renewable energy or battery storage projects, and] recover [removed: associated costs; our ability to decommission generating facilities and recover] related costs and the remaining carrying value of these facilities and related assets; [removed: changes to] MISO’s resource adequacy process establishing seasonal capacity planning reserve margin and capacity accreditation [removed: requirements that may] [added: requirements, as well as additional changes to capacity accreditation, such as the direct loss of load methodology,] impact how and when [added: existing and] new generating facilities such as IPL’s and WPL’s additional solar generation [removed: may be] [added: are] accredited with energy capacity, and may require IPL and WPL to adjust their current resource plans, to add resources to meet the requirements of MISO’s seasonal resource adequacy process, or procure capacity whereby such costs might not be recovered in rates; 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 seasonal resource adequacy process; IPL’s ability to achieve certain aggregate summer capacity factors under the consumer protection plan for its up to 400 MW of solar generation projects; the rates paid to transmission operators and how those costs are recovered from customers, including our ability to continue to use a transmission rider in Iowa; our ability to site, construct and recover costs for new natural gas pipelines; our ability to recover costs to upgrade our electric and gas distribution systems; the amount of certain sources of energy we must use, such as renewable sources; our ability to purchase generating facilities and recover the costs associated therewith; our ability to sell utility assets and any conditions placed upon the sale of such assets; our ability to enter into purchased power agreements and recover the costs associated therewith; the allocation of expenditures by transmission companies on transmission network upgrades and our ability to recover costs associated therewith; reliability; safety; the issuance of securities and ability to use other financing arrangements for our renewable energy projects; accounting matters; and transactions between affiliates.

These laws and regulations have imposed, and proposed laws and regulations could impose in the future, additional costs on our utility [removed: operations.][added: operations and requirements that impact our ability to continue operating electric generating units.]

Our future plans and existing operations may be impacted by changing expectations, including [removed: heightened emphasis on] environmental and social justice concerns related to [removed: supporting an equitable transition to cleaner] [added: renewable] energy and a low-carbon economy.

Actions related to global climate change and reducing greenhouse gas (GHG) emissions could negatively impact us - We have established [added: voluntary] GHG reduction goals and continue to review our [removed: strategy] [added: strategy; however, the ability to achieve our voluntary GHG reduction goals] and [added: implement] our [removed: role in supporting the transition] [added: strategy is subject] to [removed: a low-carbon economy.][added: uncertainties as to how climate change concerns will ultimately impact us and various factors that may be out of our control.]

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 [added: investors may] not buy our debt securities, which may cause our cost of capital to increase.

The extent of the [removed: EPA’s] [added: U.S. Environmental Protection Agency’s] proposed rules to regulate GHG emissions at fossil-fuel fired electric generating units and specific impacts, including state plans to implement the emissions reductions, remains uncertain.

We are vulnerable to potential risks associated with [removed: transition to a lower-carbon economy] [added: the construction of electric generating units] that may extend to our supply chain and natural gas operations.

This could result in rapid increased demand for alternative non-fossil [added: fuel] energy sources and economy-wide electrification.

The [removed: IRA] [added: Inflation Reduction] Act [added: of 2022] allows for the sale or transfer of eligible renewable tax credits to other taxpayers.

We [added: have sold, and continue to] plan to [removed: sell] [added: sell,] a substantial amount of our eligible renewable tax credits.

The inability to sell renewable tax credits at reasonable terms, or [removed: if] [added: the determination that] renewable tax credits that we generate or sell are [removed: determined to] not [removed: be] eligible or [added: are] eligible at a different rate, could materially impact our tax credit carryforward position or result in liability to purchasers of the tax [removed: credits.][added: credits, which could subject us to significant litigation, liability and costs.]

[removed: Repeal or amendment of the IRA Act, or portions of the IRA Act,] [added: These factors] could [removed: have an adverse] [added: negatively] impact [removed: on] our financial condition and results of operations.

[added: If the federal or state tax rates are increased, or] we [added: become subject to a corporate alternative minimum tax, we] may experience adverse impacts to our financial condition and results of operations until those rates are reflected in our regulatory filings.

Our utility business is developing [removed: battery] [added: energy] storage facilities, which are expected to generate investment tax credits.

The [removed: IRA] [added: Inflation Reduction] Act [added: of 2022] introduced new labor requirements that are required to qualify for the full value of renewable tax credits.

The competitive employment market also increases the amounts we pay our employees in critical [removed: positions.][added: positions, which we may be unable to recover in rates.]

We are also subject to collective bargaining agreements covering approximately [removed: 1,800] [added: 1,700] employees.

[removed: 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 risks related to inflation - We have [removed: recently] experienced a significant increase in inflation.

Inflation may also cause interest rates to [removed: increase,] [added: increase or stay elevated,] increasing our cost of capital.

We may incur material post-closing adjustments related to past asset and business divestitures - We have sold certain non-utility subsidiaries [removed: such as Whiting Petroleum Corporation (Whiting Petroleum).][added: and may continue to incur liabilities relating to our previous ownership of, or the transactions pursuant to which we disposed of, these subsidiaries and assets.]

The impacts on our operations include: our ability to site and construct new energy facilities, such as renewable energy, energy storage projects, or natural gas-fired electric generating units, and recover associated costs; our ability to decommission generating facilities

Research and development of technologies, innovations, and advancements may not evolve as anticipated in order to provide cost-effective alternatives to traditional energy sources.

We could suffer financial loss, reputational damage, litigation, or other negative repercussions if we are unable to meet our voluntary GHG reduction goals.

Changing economic conditions and drivers to support significant load growth, including data centers, could influence electric demand.

This could affect the timing of retirement for our existing coal-fired electric generating units, and our need to add new fossil-fueled generation resources due to growing electric loads.

Repeal or amendment of the Inflation Reduction Act of 2022, or portions of the Inflation Reduction Act of 2022, could have an adverse impact on our financial condition and results of operations, including, but not limited to, a material increase in customer costs, a material decrease in cash flows from operating activities, which could impact metrics used by rating agencies, and a negative impact on the economics of future planned renewable and energy storage projects.

If energy storage facilities are not completed in the anticipated timeframe or investment tax credits are not able to be generated or sold due to the repeal or amendment of the Inflation Reduction Act of 2022, we may experience adverse impacts on our financial condition and results of operations.

Energy demand may decrease due to many things, including economic conditions, proliferation of customer and third party-

Demand for energy from high usage customers may impact our business - The ability to serve significant new commercial or industrial customers on contract rates, including data centers, may require certain regulatory approvals, and the activities and costs related to the construction, acquisition or contracts for additional generation capacity and transmission required to meet the high demands of such customers could be significant.

The inability or delays in obtaining regulatory approvals or securing additional capacity or transmission, due to supply chain risk, operational risk, or other factors, may impact our ability, or the cost, to provide energy to new customers, the contract rates may not fully recover the costs, the contracts may increase counterparty credit risk, and the costs to provide service may be higher than expected.

The contract rates for high usage customers are subject to regulatory approvals and our regulatory authorities may change the rates we can charge and the costs that can be recovered.

A high usage customer may decide not to take energy, take less energy than anticipated, or not take service on the anticipated schedule, due to changes in business needs, construction delays, technological advances that improve energy efficiency, or other factors, which may result in lower demand for energy than anticipated.

The addition of high usage customers may increase the concentration of sales, and increase revenue and earnings volatility.

This includes threats from nation-state actors (such as VOLT TYPHOON and SALT TYPHOON), which have demonstrated an increased focus on targeting critical industries, including telecommunications and energy.

These risks include: the inability to obtain necessary regulatory approvals and permits in a timely

Insurance coverage may not continue to be available at all, or at rates or terms similar to those presently available to us.

In addition, our insurance may not be sufficient or effective under all circumstances and against all hazards or liabilities to which we may be subject.

Any losses for which we are not fully insured or that are not covered by insurance at all could materially adversely affect our results of operations and financial position.

lower sales and revenues, which may not be replaced or recovered in rates, or rate recovery may be delayed.

Any work stoppage experienced in connection with negotiations of

| | | | 21 | | | | | |

Any potential liability depends on a number of factors outside of our control.

IPL and WPL have entered into conditional commitments with the U.S. Department of Energy’s Loan Programs Office for loan guarantees of approximately $3 billion in aggregate and WPL has been selected for additional grants.

The inability to access these funds due to federal action or other reasons may increase our costs and interest rates.

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public or contractors coming into contact with our infrastructure, and employee and public safety.

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.

However, the ability to achieve our GHG reduction goals and implement our strategy is subject to uncertainties as to how climate change concerns will ultimately impact us and various factors that may be out of our control.

If the federal or state tax rates are increased,

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.

In addition, this MDA includes certain financial information for [removed: 2023] [added: 2024] compared to [removed: 2022.][added: 2023.]

Refer to MDA in the combined [removed: 2022] [added: 2023] [Form [removed: 10-K](http://www.sec.gov/Archives/edgar/data/352541/000035254123000017/lnt-20221231.htm)] [added: 10-K](https://www.sec.gov/Archives/edgar/data/352541/000035254124000014/lnt-20231231.htm)] for details on certain financial information for [removed: 2022] [added: 2023] compared to [removed: 2021.][added: 2022.]

Alliant Energy’s mission and purpose are supported by a strategy focused on meeting [removed: the] evolving [removed: expectations of customers while] [added: customer expectations,] providing an attractive return for investors, and [removed: pursuing] [added: advancing] emerging technologies [removed: and] [added: with] safe, [removed: sustainable methods of] [added: secure] energy production.

- Alliant Energy, IPL and WPL [removed: currently] [added: have utilized, and] expect to [removed: utilize] [added: continue to utilize,] various provisions of the Inflation Reduction Act of 2022 to enhance tax benefits expected from wind, solar and [removed: battery] [added: energy] storage projects in Iowa and Wisconsin, including transferring certain future tax credits from such projects to other corporate taxpayers.

The Inflation Reduction Act of 2022 is expected to result in more cost benefits for IPL’s and WPL’s customers, higher rate base amounts, and improvements in long-term cash flows over the life of the solar, [removed: battery] [added: energy] storage and wind [removed: repowering] [added: refurbishment] projects.

Refer to [Note 1(c)](#i1fc9d0e18c654199a6dadea9bc41997a_211) for discussion of [added: $216 million and] $98 million of proceeds from renewable tax credits transferred to other corporate taxpayers in [removed: 2023.][added: 2024 and 2023, respectively.]

- IPL maintaining flat base rates for its retail electric and gas customers [added: from 2021 through September 30, 2024, as well as a retail electric base rate moratorium from October 2025 through September 2029 approved by the IUC] in [removed: 2021, 2022 and 2023.][added: IPL’s most recent retail electric rate review.]

- In [removed: 2023,] [added: July 2024,] the U.S. Department of Energy Office of Clean Energy [removed: selected the] [added: Demonstrations awarded WPL’s] Columbia Energy Storage Project, [removed: a first of its kind in the U.S.,] [added: an approximately] 20 MW [added: compressed] CO2-based long-duration energy storage system at the [removed: retiring coal-fired] Columbia [added: Energy Center] site, [removed: for award negotiations to receive] up to [added: approximately] $30 million in grant [removed: funding.][added: funding during construction of the project.]

[removed: Any] [added: If finalized, any] grant proceeds would reduce the cost of the project for WPL’s customers.

Making customer-focused investments - Alliant Energy’s strategic priorities include making significant customer-focused investments toward [removed: cleaner and] more reliable, resilient, and sustainable customer energy solutions.

Alliant Energy’s strategy drives a capital allocation process focused on: 1) transitioning its generation portfolio to meet the growing interest [added: and needs] of customers for reliable and sustainable sources of energy, 2) upgrading its electric and gas distribution systems to strengthen safety, reliability and resiliency, as well as enable distributed energy solutions in its service territories, and 3) enhancing its customers’ and employees’ experience with evolving technology and greater flexibility.

[added: Existing Natural Gas-Fired Electric Generating Unit Improvements] - [removed: Requested] [added: In April 2024, the] PSCW [removed: approval] [added: issued orders authorizing WPL] to construct improvements at the [added: existing] natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility, which would increase the capacity and efficiency of the EGUs.

A decision from the PSCW is currently expected [removed: by] [added: in] the second quarter of [removed: 2024.][added: 2025.]

Currently, approximately [removed: 27%] [added: 28%] of Alliant Energy’s electric distribution system is underground.

- Alliant Energy continues to partner with its commercial and industrial customers [added: in Iowa and Wisconsin] to help develop renewable solutions to [removed: enhance] [added: support] their sustainability [removed: initiatives, including various customer- and community-hosted solar facilities in Iowa and Wisconsin.][added: initiatives.]

[removed: -] Alliant Energy has various development-ready sites throughout [removed: Iowa and Wisconsin,] [added: Iowa,] including the [removed: 1,300-acre] Big Cedar Industrial Center Mega-site in Cedar Rapids, Iowa, and the [removed: 465-acre] Prairie View Industrial Center Super Park in Ames, [removed: Iowa, which are rail-served, ready-to-build manufacturing and industrial sites in close proximity to the regional airport, interstate freeways and IPL’s electric services.][added: Iowa.]

Financial Results Overview - The table below includes [added: diluted] EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures.

Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of [removed: segment] performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance.

| Utilities and Corporate Services | | | [removed: $724] [added: $722] | | | | | | [removed: $2.86] [added: $2.81] | | | | | | [removed: $690] [added: $724] | | | | | | [removed: $2.74] [added: $2.86] | | |

| ATC Holdings | | | [removed: 35] [added: 40] | | | | | | [removed: 0.14] [added: 0.16] | | | | | | [removed: 29] [added: 35] | | | | | | [removed: 0.12] [added: 0.14] | | |

| Non-utility and Parent | | | [removed: (56)] [added: (72)] | | | | | | [removed: (0.22)] [added: (0.28)] | | | | | | [removed: (33)] [added: (56)] | | | | | | [removed: (0.13)] [added: (0.22)] | | |

| Alliant Energy Consolidated | | | [removed: $703] [added: $690] | | | | | | [removed: $2.78] [added: $2.69] | | | | | | [removed: $686] [added: $703] | | | | | | [removed: $2.73] [added: $2.78] | | |

Alliant Energy’s Utilities and Corporate Services net income [removed: increased] [added: decreased] by [removed: $34] [added: $2] million in [removed: 2023] [added: 2024] compared to [removed: 2022.][added: 2023.]

Alliant Energy’s Non-utility and Parent net income decreased by [removed: $23] [added: $16] million in [removed: 2023] [added: 2024] compared to [removed: 2022,] [added: 2023,] primarily due to higher [removed: interest] [added: financing] expense.

Net Income Variances - The following items contributed to increased (decreased) net income for [removed: 2023] [added: 2024] compared to [removed: 2022] [added: 2023] (in millions):

| Changes in electric utility (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66303)) | | | [removed: ($76)] [added: $27] | | | | | | [removed: ($98)] [added: ($14)] | | | | | | [removed: $22] [added: $41] | | |

| Changes in gas utility (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66304)) | | | [removed: (102)] [added: (75)] | | | | | | [removed: (51)] [added: (50)] | | | | | | [removed: (51)] [added: (25)] | | |

| Changes in other utility | | | [removed: 3] [added: 2] | | | | | | [removed: 3] [added: —] | | | | | | [removed: —] [added: 2] | | |

| Changes in total revenues | | | [removed: (178)] [added: (46)] | | | | | | [removed: (146)] [added: (64)] | | | | | | [removed: (29)] [added: 18] | | |

| Changes in electric production fuel and purchased power (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66305)) | | | [removed: 94] [added: 108] | | | | | | [removed: 101] [added: 13] | | | | | | [removed: (8)] [added: 96] | | |

| Changes in electric transmission service (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66306)) | | | [removed: (10)] [added: (30)] | | | | | | [removed: (13)] [added: 3] | | | | | | [removed: 3] [added: (33)] | | |

| Changes in cost of gas sold (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66307)) | | | [removed: 90] [added: 75] | | | | | | [removed: 40] [added: 43] | | | | | | [removed: 49] [added: 33] | | |

| Changes in other operation and maintenance (Refer to [details below](#i29dd73abc2114eb3bf707729382758d7_66308)) | | | [removed: 29] [added: (1)] | | | | | | [removed: 16] [added: (5)] | | | | | | [removed: 7] [added: (8)] | | |

| Changes in taxes other than income taxes | | | [removed: (5)] [added: (7)] | | | | | | [removed: —] [added: (3)] | | | | | | [removed: (5)] [added: (4)] | | |

| Changes in total operating expenses | | | [removed: 193] [added: (11)] | | | | | | [removed: 137] [added: (25)] | | | | | | [removed: 49] [added: 7] | | |

| Changes in operating income | | | [removed: 15] [added: (57)] | | | | | | [removed: (9)] [added: (89)] | | | | | | [removed: 20] [added: 25] | | |

| Changes in interest expense (Higher primarily due to financings completed in [removed: 2023 and 2022,] [added: 2024] and [removed: higher interest rates)] [added: 2023)] | | | [removed: (69)] [added: (55)] | | | | | | [removed: (7)] [added: (22)] | | | | | | [removed: (28)] [added: (16)] | | |

| [removed: Changes] [added: Changes] in [removed: equity] income [removed: from unconsolidated investments, net] [added: taxes] (Refer to [removed: [Note 6](#i1fc9d0e18c654199a6dadea9bc41997a_268)] [added: [Note](#i1fc9d0e18c654199a6dadea9bc41997a_298) [1](#i1fc9d0e18c654199a6dadea9bc41997a_298)[1](#i1fc9d0e18c654199a6dadea9bc41997a_298)] for details) | | | [removed: 10] [added: 118] | | | | | | [removed: —] [added: 71] | | | | | | [removed: —] [added: 49] | | |

| Changes in AFUDC [removed: (Higher primarily] [added: (Primarily] due to [removed: higher] [added: changes in] levels of CWIP balances related to solar generation and [removed: battery storage)] [added: energy storage, and IPL’s refurbishment of the existing Franklin County wind farm)] | | | [removed: 40] [added: (25)] | | | | | | [removed: 10] [added: 22] | | | | | | [removed: 30] [added: (47)] | | |

| Changes in total other income and deductions | | | [removed: (16)] [added: (74)] | | | | | | [removed: 7] [added: 14] | | | | | | [removed: 4] [added: (74)] | | |

- Alliant Energy’s resource plan continues to add resources in Iowa and Wisconsin, which is expected to result in continued reliability and affordability for its utility customers.

From 2022 through 2024, Alliant Energy completed projects that resulted in approximately 1,500 MW of additional zero-fuel cost solar generation resources in aggregate (WPL completed 1,089 MW of solar generation in Wisconsin in 2022-2024 and IPL completed 400 MW of solar generation in Iowa in 2024), which generate renewable tax credits that are provided to its electric customers.

IPL’s retail electric and gas customers began receiving these benefits with the new base rates effective October 1, 2024.

- Significant fuel cost reductions beginning in 2023 with the completion of various solar facilities.

- Completion of a restructuring and voluntary employee separation program in 2024, which is expected to reduce operation and maintenance expenses in the future.

- IPL and WPL have entered into conditional commitments with the U.S. Department of Energy’s Loan Programs Office for loan guarantees of approximately $1.4 billion and $1.6 billion, respectively.

If finalized, such loans would provide low interest financing for IPL’s and WPL’s expected construction of renewable generation and energy storage projects.

In addition, in October 2024, the U.S. Department of Energy Office of Grid Deployment selected WPL’s Smart Power Automation for Rural Communities program application to move into the final stage of award negotiations for up to $50 million in grant funding under the Grid Resilience and Innovation Partnerships Program.

If finalized, any grant proceeds would reduce the cost of the projects for WPL’s customers.

- Over the next five years, Alliant Energy currently plans to develop and/or acquire new generation investments to add flexibility with evolving load growth, including approximately 1,200 MW of new wind and solar generation in aggregate, approximately 1,000 MW of energy storage, approximately 750 MW of new natural gas resources, refurbishments at approximately 600 MW of existing wind farms, and improvements at approximately 650 MW of existing natural gas-fired EGUs and the conversion of existing coal-fired EGUs to natural gas.

Alliant Energy is currently evaluating the impact of potential additional large load growth customers and MISO’s seasonal resource adequacy requirements on its resource plans and will update these generation investment plans as needed in the future.

- Completion of new solar generation at WPL (1,089 MW in Wisconsin from 2022-2024) and IPL (400 MW in Iowa in 2024), and IPL’s refurbishment of the existing Franklin County wind farm in Iowa in 2024.

Currently, approximately 1,000 miles of underground fiber optic routes have been installed.

- The IUC’s order for IPL’s most recent retail electric rate review includes the creation of an individual customer rate tariff, allowing IPL to attract new load growth to its service territory.

In addition, Iowa’s Major Economic Growth Attraction program and Wisconsin’s sales and use tax exemption for qualified data centers, encourage economic development in Alliant Energy’s service territory.

- IPL has entered into electric service agreements with two new customers, who currently expect to build data centers at the Big Cedar Industrial Center in Cedar Rapids, Iowa in IPL’s service territory.

These agreements include aggregate, maximum demands of approximately 1.9 gigawatts.

The electric service agreements are subject to IUC approval under the individual customer rate tariff that was included in the IUC’s September 2024 order for IPL’s retail electric rate review.

The actual timing and amount of increases in IPL’s load are subject to various factors, including interconnections and actual customer demand, and any executed or future agreements with customers are not expected to result in immediate increases in load.

- Various development-ready sites, which are rail-served and in close proximity to a variety of transportation options, are located throughout Alliant Energy’s service territories.

| | | | 2024 | | | | | | | | | | | | 2023 | | | | | | | | |

The decrease was primarily due to an asset valuation charge for IPL’s Lansing Generating Station as a result of the IUC order for IPL’s retail electric rate review, estimated temperature impacts on retail electric and gas sales, restructuring and voluntary separation charges, an ARO charge allocated to the steam business at IPL due to the revised CCR Rule, higher depreciation and financing expenses, and lower AFUDC.

These items were partially offset by higher revenue requirements from capital investments.

| Asset valuation charge for IPL’s Lansing Generating Station in 2024 (Refer to [Note 2](#i1fc9d0e18c654199a6dadea9bc41997a_250) for details) | | | (60) | | | | | | (60) | | | | | | — | | |

| Changes in depreciation and amortization (Higher primarily due to solar generation placed in service in 2024 and 2023, as well as WPL’s amortization of liquidated damages related to West Riverside procurement contracts, which resulted in reductions to depreciation and amortization expenses in 2023, and updated electric depreciation rates for IPL effective October 1, 2024) | | | (96) | | | | | | (16) | | | | | | (77) | | |

| | | | 2024 | | | | | | 2023 | | | | | | | | | | | | 2024 | | | | | | 2023 | | | | | | | | | | | | 2024 | | | | | | 2023 | | | | | | 2024 | | | | | | 2023 | | |

| Retail | | | $3,009 | | | | | | $3,008 | | | | | | | | | | | | 24,569 | | | | | | 24,940 | | | | | | | | | | | | $419 | | | | | | $495 | | | | | | 43,489 | | | | | | 46,405 | | |

| | | | $3,372 | | | | | | $3,345 | | | | | | | | | | | | 33,029 | | | | | | 32,587 | | | | | | | | | | | | $465 | | | | | | $540 | | | | | | 166,875 | | | | | | 161,582 | | |

| Retail | | | $1,662 | | | | | | $1,661 | | | | | | | | | | | | 13,620 | | | | | | 13,909 | | | | | | | | | | | | $223 | | | | | | $273 | | | | | | 21,640 | | | | | | 23,128 | | |

| | | | $1,747 | | | | | | $1,761 | | | | | | | | | | | | 15,540 | | | | | | 16,172 | | | | | | | | | | | | $250 | | | | | | $300 | | | | | | 64,715 | | | | | | 66,360 | | |

| | | | $1,625 | | | | | | $1,584 | | | | | | | | | | | | 17,489 | | | | | | 16,415 | | | | | | | | | | | | $215 | | | | | | $240 | | | | | | 102,160 | | | | | | 95,222 | | |

Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes decreased 1% in 2024 compared to 2023, primarily due to changes in sales volumes at IPL’s industrial customers due to standby service customers that can use other generation, and changes in temperatures.

| IPL | | | ($14) | | | | | | ($1) | | | | | | ($13) | | | | | | | | | | | | | | | ($12) | | | | | | ($8) | | | | | | ($4) | | | | | | | | | | | |

| Higher revenue requirements (a)(b) | | | $240 | | | | | | $85 | | | | | | $155 | | |

| Deferral of incremental solar generation construction costs at WPL in 2024 (Refer to [Note 3](#i1fc9d0e18c654199a6dadea9bc41997a_253)) | | | 12 | | | | | | — | | | | | | 12 | | |

| Lower revenues at IPL due to credits on customers’ bills through the tax benefit rider in 2024 (partially offset by changes in income taxes) (a) | | | (16) | | | | | | (16) | | | | | | — | | |

| | | | $27 | | | | | | ($14) | | | | | | $41 | | |

(a)In September 2024, the IUC issued an order authorizing an annual base rate increase of $185 million for IPL’s retail electric customers, with customers receiving partially offsetting credits for the first 12 months through a tax benefit rider, for the October 2024 through September 2025 forward-looking Test Period.

Rate changes were effective October 1, 2024, which reflect revenue requirement impacts of increasing electric rate base including investments in solar generation, updated depreciation rates, and certain incremental costs incurred resulting from the 2020 derecho windstorm.

In addition, effective October 1, 2024, IPL’s renewable energy rider was discontinued, and certain production tax credits are credited to IPL’s retail electric customers through IPL’s fuel-related cost recovery mechanism.

- Alliant Energy’s Clean Energy Blueprint, also known as the roadmap for its transition to cleaner energy, continues to add clean energy resources in Iowa and Wisconsin.

In Wisconsin, WPL completed 639 MW of solar generation in 2023, adding to the 250 MW of solar generation placed in service in 2022, and expects to add another 200 MW of solar generation in 2024, resulting in approximately 1,100 MW of solar generation resources in aggregate.

In Iowa, IPL expects to complete 400 MW of solar generation by the end of 2024.

Completion of these projects is expected to result in approximately 1,500 MW of additional zero-fuel cost solar generation resources for Alliant Energy in aggregate by the end of 2024.

The execution of Alliant Energy’s strategy is expected to result in cost benefits for its utility customers by continuing to add renewable energy projects that generate fuel cost benefits and renewable tax credits that are provided to its electric customers.

- Significant fuel cost reductions achieved in 2021, 2022 and 2023 as a result of shortening the term of IPL’s DAEC PPA by 5 years, and beginning in 2023 with the May 2023 retirement of Lansing.

Alliant Energy, with support from various project partners, currently expects to submit project plans to the PSCW in 2024 after award negotiations with the DOE are finished.

- Levelized cost recovery mechanism for the remaining net book value of Edgewater Unit 5, which helps reduce customer costs.

- Development and acquisition of additional renewable energy, including approximately 1,100 MW of solar generation at WPL with in-service dates in 2022-2024, approximately 275 MW of battery storage at WPL with in-service dates in 2024 and 2025, and approximately 400 MW of solar generation at IPL with in-service dates in 2024.

In addition, IPL and WPL continue to evaluate additional opportunities to add more renewable generation, including repowering of existing wind farms and additional solar generation and distributed energy resources, including community solar and small-scale energy storage systems.

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

Four such facilities were completed in Wisconsin in 2021 and 2022, and several more are currently planned to be completed in 2024 in Iowa and Wisconsin.

- Alliant’s Energy was named a Top Utility in Economic Development by Site Selection Magazine for the fifth year in a row, and was named a Top Utility by Business Facilities Magazine for the fourth year in a row.

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.

| | | | 2023 | | | | | | | | | | | | 2022 | | | | | | | | |

The increase was primarily due to higher revenue requirements and AFUDC from capital investments and lower other operation and maintenance expenses at IPL and WPL.

These items were partially offset by higher interest expense, lower retail electric and gas sales primarily due to temperature impacts, and higher depreciation expense.

| Changes in non-utility | | | (3) | | | | | | — | | | | | | — | | |

| Changes in depreciation and amortization (Refer to [Note 2](#i1fc9d0e18c654199a6dadea9bc41997a_250) for discussion of reductions to WPL’s depreciation and amortization expense, which was partially offset by WPL’s solar generation placed in service in 2022) | | | (5) | | | | | | (7) | | | | | | 3 | | |

| Changes in Other (Refer to [Note 13(a)](#i1fc9d0e18c654199a6dadea9bc41997a_304) for details of IPL’s qualified pension plan settlement losses in 2022) | | | 3 | | | | | | 4 | | | | | | 2 | | |

| Changes in income taxes (Refer to [Note 12](#i1fc9d0e18c654199a6dadea9bc41997a_298) for details) | | | 18 | | | | | | 8 | | | | | | 6 | | |

| | | | 2023 | | | | | | 2022 | | | | | | | | | | | | 2023 | | | | | | 2022 | | | | | | | | | | | | 2023 | | | | | | 2022 | | | | | | 2023 | | | | | | 2022 | | |

| Retail | | | $3,008 | | | | | | $3,019 | | | | | | | | | | | | 24,940 | | | | | | 25,409 | | | | | | | | | | | | $495 | | | | | | $588 | | | | | | 46,405 | | | | | | 55,021 | | |

| | | | $3,345 | | | | | | $3,421 | | | | | | | | | | | | 32,587 | | | | | | 32,071 | | | | | | | | | | | | $540 | | | | | | $642 | | | | | | 161,582 | | | | | | 159,833 | | |

| Retail | | | $1,661 | | | | | | $1,747 | | | | | | | | | | | | 13,909 | | | | | | 14,270 | | | | | | | | | | | | $273 | | | | | | $317 | | | | | | 23,128 | | | | | | 28,492 | | |

| | | | $1,761 | | | | | | $1,859 | | | | | | | | | | | | 16,172 | | | | | | 16,475 | | | | | | | | | | | | $300 | | | | | | $351 | | | | | | 66,360 | | | | | | 71,756 | | |

| | | | $1,584 | | | | | | $1,562 | | | | | | | | | | | | 16,415 | | | | | | 15,596 | | | | | | | | | | | | $240 | | | | | | $291 | | | | | | 95,222 | | | | | | 88,077 | | |

| IPL | | | ($1) | | | | | | $16 | | | | | | ($17) | | | | | | | | | | | | | | | ($8) | | | | | | $5 | | | | | | ($13) | | | | | | | | | | | |

| Higher revenues at IPL related to changes in the electric transmission service cost rider (mostly offset in electric transmission service expense) (Refer to [Electric Transmission Service Expense Variances](#i29dd73abc2114eb3bf707729382758d7_66306) below) | | | 19 | | | | | | 19 | | | | | | — | | |

| Higher revenues at IPL related to changes in the renewable energy rider (mostly offset by changes in income taxes) | | | 13 | | | | | | 13 | | | | | | — | | |

| | | | ($76) | | | | | | ($98) | | | | | | $22 | | |

Refer to [Note 2](#i1fc9d0e18c654199a6dadea9bc41997a_250) for discussion of deferred fuel-related costs that were outside the approved fuel monitoring range in 2023, 2022 and 2021.

| | | | ($102) | | | | | | ($51) | | | | | | ($51) | | |

| | | | $94 | | | | | | $101 | | | | | | ($8) | | |

(b)Purchased power expense decreased primarily due to lower prices for electricity purchased by IPL and WPL from MISO wholesale energy markets, and decreased volumes of electricity purchased due to lower retail and wholesale electric sales and less reliance on wholesale energy market purchases due to higher dispatch of IPL’s and WPL’s natural gas-fired EGUs.

| | | | ($10) | | | | | | ($13) | | | | | | $3 | | |

| | | | $90 | | | | | | $40 | | | | | | $49 | | |

| Lower incentive compensation expense | | | $7 | | | | | | $4 | | | | | | $3 | | |

| Non-utility Travero (mostly offset by lower non-utility revenues) | | | 4 | | | | | | — | | | | | | — | | |

Alliant Energy’s primary focus is to provide regulated electric and natural gas service to approximately 1,000,000 electric and approximately [removed: 425,000] [added: 430,000] natural gas customers in the Midwest through its two public utility subsidiaries, IPL and WPL.

IPL provides utility services to incorporated communities as directed by the [removed: IUB] [added: IUC] 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, [removed: 2023,] [added: 2024,] IPL supplied electric and natural gas service to approximately 500,000 and [removed: 225,000] [added: 230,000] retail customers, respectively, in Iowa.

IPL also sells electricity to wholesale customers in [removed: Minnesota, Illinois] [added: Minnesota] and [removed: Iowa.][added: Illinois.]

At December 31, [removed: 2023,] [added: 2024,] WPL supplied electric and natural gas service to approximately 500,000 and 200,000 retail customers, respectively.

Corporate Venture Investments - includes various minority ownership interests in regional and national venture funds, including a global coalition of energy companies working together to help [removed: advance the transition towards a cleaner, more sustainable, and inclusive energy future, by identifying] [added: identify] and [removed: researching] [added: research] innovative technologies and business models within the emerging energy economy.

Sheboygan Falls Energy Facility - is a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is currently leased to WPL through [removed: 2039.][added: 2044.]

Refer to [removed: [Note 10](#i1fc9d0e18c654199a6dadea9bc41997a_292)] [added: [Note](#i1fc9d0e18c654199a6dadea9bc41997a_292) [9](#i1fc9d0e18c654199a6dadea9bc41997a_292)] for additional information on WPL’s Sheboygan Falls Energy Facility lease.

Travero - is a [removed: 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; wind turbine blade recycling services; and a rail-served warehouse in Iowa.

Development-ready Sites - includes various rail-served and ready-to-build manufacturing and industrial sites throughout [removed: Iowa and Wisconsin,] [added: Alliant Energy’s service territories,] with access to various [removed: airports, interstate freeways] [added: airports] and [removed: Alliant Energy’s electric services.][added: interstate freeways.]

We constantly strive to attract, retain and develop a [removed: diverse and] qualified workforce of high-performing [removed: employees, and create] [added: employees] and foster an environment of [removed: inclusion and belonging for all employees.][added: high levels of engagement.]

Employees - At December 31, [removed: 2023,] [added: 2024,] 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 August 31, [removed: 2024.][added: 2028.]

Public safety is equally [removed: important] [added: important,] as we interact with our customers to provide energy to their homes and businesses.

Through a variety of health, welfare and compensation programs, we offer employees choice and control, [removed: while supporting] [added: and help support] their financial, physical, and mental well-being.

[removed: Tools] [added: We provide tools] and resources [removed: are provided] to employees to help maintain and improve their health.

Short- and long-term incentive plans [removed: are designed with] [added: have] a mix of operational and financial metrics that align employees with strategic corporate [removed: and social] goals.

- a 401(k) savings plan with an employer [added: contribution and employer] match;

- Volunteer Grants and [added: a] Matching Gifts program.

Annually, Alliant Energy awards up to 25 scholarships to children of its current employees and eligible [removed: retirees who have achieved excellent records in high school who are pursuing a higher education.][added: retirees.]

[removed: Scholarship award] [added: Award] recipients [added: have achieved excellent records in high school, are pursuing a higher education, and] may enroll in any accredited two- or four-year college, university or vocational-technical school in the U.S.

[removed: Diversity, Equity, Inclusion and Belonging (DEI&B)] [added: Employee Engagement] - A [removed: diverse, equitable and inclusive] workplace where everyone feels [removed: like they belong] [added: meaningful connection to work and company goals] is crucial for the success and retention of our employees, to attract future talent and to execute our purpose-driven strategy to serve our customers and build stronger communities.

It is one of our Values - “Care for others: Together we create a workplace where people feel like they [removed: belong and] can use their [removed: unique] backgrounds, talents and perspectives to their fullest potential.” Alliant Energy [removed: is driven by DEI&B and] believes the achievement of its strategic objectives can only be achieved with a focused and engaged workforce.

Talent Development and Workforce Readiness - We support [added: all] employees in [removed: the growth of] their [removed: careers through] [added: skill development and career growth, offering] several training [removed: opportunities] [added: opportunities, development programs] and [added: tuition reimbursement, as well as leadership] development [removed: programs.][added: and succession planning.]

[removed: As we] [added: To help] attract and introduce a [removed: diverse pool] [added: wide range] of candidates to our industry, we have [removed: an] early careers [removed: program] [added: programs] that [removed: includes] [added: include] apprenticeships, youth programs (high school) and internships (college).

[removed: IUB] [added: IUC] - IPL is subject to regulation by the [removed: IUB] [added: IUC] for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, the construction of EGUs, and the acquisition, sale or lease of assets with values that exceed 3% of IPL’s revenues.

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

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

The [removed: IUB] [added: IUC] must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed, subject to certain exceptions.

The historical test periods may be adjusted for certain known and measurable changes to capital investments, cost of capital and operating and maintenance expenses consistent with [removed: IUB] [added: IUC] rules and regulations.

The [removed: IUB] [added: IUC] has rules that establish minimum filing requirements for rate reviews using a forward-looking test period, and a related subsequent proceeding review after the close of the forward-looking test period.

In addition, the rules require that IPL must receive an order from the [removed: IUB] [added: IUC] related to the subsequent proceeding review before it can file another rate review.

Energy Efficiency - In accordance with Iowa law, IPL is required to file an energy efficiency plan (EEP) every five years with the [removed: IUB.][added: IUC.]

[removed: IUB] [added: IUC] approval demonstrates that IPL’s EEP is reasonably expected to achieve cost-effective delivery of the energy efficiency programs.

Electric Generating Units - IPL must obtain a certificate of public convenience, use and necessity (GCU Certificate) from the [removed: IUB] [added: IUC] in order to construct a new, or significantly alter (including fuel switching) an existing, EGU [added: or energy storage facility] located in Iowa with [added: a nameplate generating capacity of] 25 MW or [removed: more of nameplate generating capacity.][added: more.]

IPL’s ownership and operation of EGUs (including those located outside the state of Iowa) to serve Iowa customers is subject to retail utility rate regulation by the [removed: IUB.][added: IUC.]

Gas Pipeline Projects - IPL must obtain a pipeline permit from the [removed: IUB] [added: IUC] related to the siting of utility gas pipelines in Iowa that will be operated at a pressure over 150 pounds per square inch and will transport gas to a distribution system or single, large volume customer.

Advance Rate-making Principles - Iowa law allows Iowa utilities to request rate-making principles prior to making certain [removed: generation] investments in Iowa.

As a result, IPL may file for, and the [removed: IUB] [added: IUC] must render a decision on, rate-making principles for certain new EGUs located in Iowa, including any [removed: alternative] [added: alternate] energy production facility (such as a [removed: wind or solar facility, as well as battery] [added: wind, solar, energy] storage [removed: constructed in combination with these facilities),] [added: or nuclear-fired facility),] combined-cycle natural gas-fired EGU, and certain base-load EGUs with a nameplate generating capacity of 300 MW or [removed: more (such as nuclear-fired generation).][added: more.]

Upon approval of rate-making principles by the [removed: IUB,] [added: IUC,] IPL must either construct the EGU or repower the alternative energy production facility under the approved rate-making principles, or not at all.

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

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

| Alliant Energy | | | 2,998 | | | | | | 1,732 | | | | | | 58% | | |

| IPL | | | 1,043 | | | | | | 759 | | | | | | 73% | | |

| WPL | | | 1,003 | | | | | | 860 | | | | | | 86% | | |

Our efforts to advance employee engagement in our workforce include:

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

- Listening and responding: We collect and act upon feedback through employee sentiment surveys;

- Empowering: We promote and foster an engaged workforce, providing opportunities to collaborate, network, and share their insights and talents; and

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

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

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

Refer to “[Rate Matters](#i1fc9d0e18c654199a6dadea9bc41997a_106)” in MDA for discussion of IPL’s retail electric base rate moratorium from October 2025 through September 2029 approved by the IUC in IPL’s most recent retail electric rate review.

The IUC’s 2023 order for the advance rate-making principles for IPL’s 400 MW of solar generation projects placed in service in 2024 included a consumer protection plan, which monitors IPL’s achievement of certain aggregate summer capacity factors for those projects during June, July and August each calendar year over 30 years.

Actual three-year rolling average summer capacity factors will be compared to target capacity factors, which may result in surpluses or deficits that would be offset against one another and contribute to an accumulated balance in a given calendar year.

Surpluses or deficits will be capped at $3 million in aggregate per year.

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

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

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

If WPL’s coal-fired Columbia Energy Center is retired by the end of 2029, the final rule would not be applicable; however, if WPL converts Columbia Unit 1 and/or Unit 2 to natural gas, then the final rule would be applicable for the EGUs that are converted.

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

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

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

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

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

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

Alliant Energy, IPL and WPL are currently evaluating the final rule and are unable to predict with certainty future compliance impacts, including resolution of ongoing litigation; however, costs to comply with this rule could have a material impact on their financial condition and results of operations.

In May 2024, the EPA revised the CCR Rule, which significantly expands the scope of regulation, and as discussed in [Note 1](#i1fc9d0e18c654199a6dadea9bc41997a_313)[3](#i1fc9d0e18c654199a6dadea9bc41997a_313), Alliant Energy, IPL and WPL recorded additional AROs in 2024.

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

Beginning with the June 1, 2028 through May 31, 2029 planning period, MISO will implement a Direct Loss of Load methodology to determine capacity accreditation, which will incorporate forward-looking analysis, and historical resource-specific performance during periods of high system risk over the previous three years.

| Required installed capacity reserve margin | | | 15.7% | | | | | | 25.3% | | | | | | 38.6% | | | | | | 38.8% | | |

| Required unforced capacity reserve margin | | | 7.9% | | | | | | 14.9% | | | | | | 18.4% | | | | | | 25.3% | | |

| | | | 2024 | | | | | | 2023 | | | | | | 2022 | | | | | | 2024 | | | | | | 2023 | | | | | | 2022 | | |

| Revenue per KWh sold to retail customers (cents) | | | $12.20 | | | | | | $11.94 | | | | | | $12.24 | | | | | | $12.30 | | | | | | $12.21 | | | | | | $11.42 | | |

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | 15 | | | | | |

[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

| | | | 2024 | | | | | | 2023 | | | | | | 2022 | | | | | | 2024 | | | | | | 2023 | | | | | | 2022 | | |

IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa.

| Alliant Energy | | | 3,281 | | | | | | 1,755 | | | | | | 53% | | |

| IPL | | | 1,116 | | | | | | 774 | | | | | | 69% | | |

| WPL | | | 1,045 | | | | | | 868 | | | | | | 83% | | |

Alliant Energy’s corporate officers group currently has approximately 44% gender diversity and 25% ethnic diversity.

Our efforts to create a diverse, equitable and inclusive workplace have focused on reducing bias, building diverse teams, and listening to and acting on employee feedback, and include:

- learning opportunities for employees, such as inviting employees to participate in area diversity summits and supporting company-wide listening sessions, speakers and programs;

- Employee Resource Groups that foster a diverse, equitable and inclusive workplace that supports employee well-being while promoting professional development and enhancing community relationships; and

- a DEI&B Leadership Team that partners with the Human Resources department and hiring managers to attract more diverse applicants that represent the diversity of the communities we serve.

Our DEI&B initiatives also include a focus on building a diverse Board of Directors.

We believe it is in our shareowners’ best interest to have a diverse Board representing a wide breadth of experiences and perspectives.

Our Board currently has approximately 40% gender diversity and 20% ethnic diversity.

Our 2023 DEI&B accomplishments include:

- received a perfect score on the Corporate Equality Index administered by the Human Rights Campaign Foundation to benchmark LGBTQ+ rights, policies and practices;

- selected for the 2023 Bloomberg Gender-Equality Index; and

- held our fourth annual Day of Understanding, with 88% voluntary company-wide participation, where leaders facilitated conversations around creating a culture of inclusion and belonging, helping to ensure employees are seen, heard and valued.

Alliant Energy’s short- and long-term incentive compensation plans include diversity metrics to drive leadership accountability for efforts to advance a diverse and inclusive culture.

These include tuition reimbursement, and online, instructor-led and on-the-job learning formats, as well as leadership development and succession planning.

WPL is not obligated to file

While the EPA’s rules to regulate GHG issued under the authority of the CAA remain subject to further review, growing emphasis on climate change and evolving energy technologies are driving efforts to decarbonize the environment through voluntary emissions reductions.

*Clean Air Act Section 111(d)* - In 2015, the EPA issued the Clean Power Plan rule under Section 111(d) of the CAA to reduce CO2 emissions from existing fossil-fueled EGUs through broad electricity system-wide measures.

This was replaced by the Affordable Clean Energy rule in 2019, to reduce CO2 emissions from existing coal-fired EGUs through heat rate improvements.

In 2021, the U.S. Court of Appeals for the District of Columbia vacated and remanded the Affordable Clean Energy rule to the EPA for reconsideration.

In 2022, the Supreme Court issued a decision limiting the extent of the EPA’s authority under Section 111(d) to emissions reduction technologies and operational improvements.

In May 2023, the EPA proposed the revised Section 111(d) rule, which would establish emission guidelines for states to implement Best System of Emission Reduction standards for GHG emissions from existing fossil-fueled EGUs and certain combustion turbines.

The proposed requirements would be phased in beginning in 2030.

The EPA also proposed to repeal the Affordable Clean Energy rule.

The proposed standards could impact IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, Prairie Creek Generating Station Unit 3 and Louisa Generating Station, and IPL’s natural gas-fired Burlington Generating Station and Prairie Creek Generating Station Unit 4.

The proposed standards are currently not expected to impact WPL’s coal-fired Columbia Energy Center or Edgewater Generating Station given current plans to retire these EGUs prior to the proposed 2030 implementation deadline.

The EPA plans to finalize the revised Section 111(d) rule in 2024.

IPL’s Marshalltown Generating Station and WPL’s West Riverside Energy Center are currently subject to the EPA’s Section 111(b) regulation and thus would be impacted by these revised standards.

The EPA plans to finalize the revised Section 111(b) rule in 2024.

could be included in a future rule.

In 2020, revised effluent limitation guidelines (2020 Reconsideration Rule) became effective, which incorporated flexibility to the 2015 rule, including a new subcategory for coal-fired EGUs that will be retired or converted to no longer burn coal before 2028.

In 2021, the current Presidential Administration issued an Executive Order requiring the review and possible revision of environmental regulations issued during the prior Administration.

As a result, in March 2023, the EPA published a proposed supplemental rule (2023 Supplemental Rule) to revise the guidelines for steam-electric generating facilities.

The 2023 Supplemental Rule proposes to tighten some of the flexibility offered in the 2020 Reconsideration Rule for certain waste streams, while additionally proposing a newly defined legacy wastewater waste stream.

The 2020 Reconsideration Rule will remain in effect while the 2023 Supplemental Rule continues through the rule-making process.

In May 2023, the EPA published proposed amendments to the CCR Rule that would expand the scope of regulation to include coal ash ponds at sites that no longer produce electricity and inactive landfills, including some IPL and WPL facilities.

General - Electric utility operations represent the largest operating segment for Alliant Energy, IPL and WPL.

Refer to [Note [removed: 17(c)](#i1fc9d0e18c654199a6dadea9bc41997a_337)] [added: 1](#i1fc9d0e18c654199a6dadea9bc41997a_337)[6](#i1fc9d0e18c654199a6dadea9bc41997a_337)[(c)](#i1fc9d0e18c654199a6dadea9bc41997a_337)] for discussion of legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business.

For the fiscal year ended December 31, [removed: 2023][added: 2024]

[removed: ][added: ]

The aggregate market value of the voting and non-voting common equity held by nonaffiliates as of June 30, [removed: 2023:][added: 2024:]

Alliant Energy Corporation - [removed: $13.2] [added: $13.0] billion

Number of shares outstanding of each class of common stock as of January 31, [removed: 2024:][added: 2025:]

Alliant Energy Corporation, Common Stock, $0.01 par value, [removed: 256,100,293] [added: 256,692,381] shares outstanding

Portions of the Proxy Statement relating to Alliant Energy Corporation’s [removed: 2024] [added: 2025] Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.

| | | | [Item 1A. Risk Factors](#i1fc9d0e18c654199a6dadea9bc41997a_64) | | | | | | | | | | | | | | | [removed: [15](#i1fc9d0e18c654199a6dadea9bc41997a_64)] [added: [16](#i1fc9d0e18c654199a6dadea9bc41997a_64)] | | |

| | | | [Item 1B. Unresolved Staff Comments](#i1fc9d0e18c654199a6dadea9bc41997a_67) | | | | | | | | | | | | | | | [removed: [21](#i1fc9d0e18c654199a6dadea9bc41997a_67)] [added: [22](#i1fc9d0e18c654199a6dadea9bc41997a_67)] | | |

| | | | [Item 1](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[C](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[.](#i1fc9d0e18c654199a6dadea9bc41997a_3381) [Cybe](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[r](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[s](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[ec](#i1fc9d0e18c654199a6dadea9bc41997a_3381)[urity](#i1fc9d0e18c654199a6dadea9bc41997a_3381) | | | | | | | | | | | | | | | [removed: [21](#i1fc9d0e18c654199a6dadea9bc41997a_3381)] [added: [23](#i1fc9d0e18c654199a6dadea9bc41997a_3381)] | | |

| | | | [Item 2. Properties](#i1fc9d0e18c654199a6dadea9bc41997a_70) | | | | | | | | | | | | | | | [removed: [22](#i1fc9d0e18c654199a6dadea9bc41997a_70)] [added: [24](#i1fc9d0e18c654199a6dadea9bc41997a_70)] | | |

| | | | [Item 3. Legal Proceedings](#i1fc9d0e18c654199a6dadea9bc41997a_73) | | | | | | | | | | | | | | | [removed: [25](#i1fc9d0e18c654199a6dadea9bc41997a_73)] [added: [26](#i1fc9d0e18c654199a6dadea9bc41997a_73)] | | |

| | | | [Item 4. Mine Safety Disclosures](#i1fc9d0e18c654199a6dadea9bc41997a_76) | | | | | | | | | | | | | | | [removed: [25](#i1fc9d0e18c654199a6dadea9bc41997a_76)] [added: [26](#i1fc9d0e18c654199a6dadea9bc41997a_76)] | | |

| | | | [Information About Executive Officers](#i1fc9d0e18c654199a6dadea9bc41997a_79) | | | | | | | | | | | | | | | [removed: [25](#i1fc9d0e18c654199a6dadea9bc41997a_79)] [added: [26](#i1fc9d0e18c654199a6dadea9bc41997a_79)] | | |

| [Part II.](#i1fc9d0e18c654199a6dadea9bc41997a_82) | | | [Item 5. Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities](#i1fc9d0e18c654199a6dadea9bc41997a_85) | | | | | | | | | | | | | | | [removed: [26](#i1fc9d0e18c654199a6dadea9bc41997a_85)] [added: [27](#i1fc9d0e18c654199a6dadea9bc41997a_85)] | | |

| | | | [Item 6.](#i1fc9d0e18c654199a6dadea9bc41997a_88) [\[Reserv](#i1fc9d0e18c654199a6dadea9bc41997a_88)[ed](#i1fc9d0e18c654199a6dadea9bc41997a_88)[\]](#i1fc9d0e18c654199a6dadea9bc41997a_88) | | | | | | | | | | | | | | | [removed: [26](#i1fc9d0e18c654199a6dadea9bc41997a_88)] [added: [27](#i1fc9d0e18c654199a6dadea9bc41997a_88)] | | |

| | | | [Item 7A. Quantitative and Qualitative Disclosures About Market Risk](#i1fc9d0e18c654199a6dadea9bc41997a_127) | | | | | | | | | | | | | | | [removed: [44](#i1fc9d0e18c654199a6dadea9bc41997a_127)] [added: [46](#i1fc9d0e18c654199a6dadea9bc41997a_127)] | | |

| | | | [Item 8. Financial Statements and Supplementary Data](#i1fc9d0e18c654199a6dadea9bc41997a_130) | | | | | | | | | | | | | | | [removed: [44](#i1fc9d0e18c654199a6dadea9bc41997a_130)] [added: [46](#i1fc9d0e18c654199a6dadea9bc41997a_130)] | | |

| | | | | | | [Alliant Energy Corporation](#i1fc9d0e18c654199a6dadea9bc41997a_133) | | | | | | | | | | | | [removed: [45](#i1fc9d0e18c654199a6dadea9bc41997a_133)] [added: [47](#i1fc9d0e18c654199a6dadea9bc41997a_133)] | | |

| | | | | | | [Interstate Power and Light Company](#i1fc9d0e18c654199a6dadea9bc41997a_157) | | | | | | | | | | | | [removed: [51](#i1fc9d0e18c654199a6dadea9bc41997a_157)] [added: [53](#i1fc9d0e18c654199a6dadea9bc41997a_157)] | | |

| | | | | | | [Wisconsin Power and Light Company](#i1fc9d0e18c654199a6dadea9bc41997a_178) | | | | | | | | | | | | [removed: [57](#i1fc9d0e18c654199a6dadea9bc41997a_178)] [added: [59](#i1fc9d0e18c654199a6dadea9bc41997a_178)] | | |

| | | | | | | [Combined Notes to Consolidated Financial Statements](#i1fc9d0e18c654199a6dadea9bc41997a_199) | | | | | | | | | | | | [removed: [63](#i1fc9d0e18c654199a6dadea9bc41997a_199)] [added: [65](#i1fc9d0e18c654199a6dadea9bc41997a_199)] | | |

| | | | | | | | | | [1. Summary of Significant Accounting Policies](#i1fc9d0e18c654199a6dadea9bc41997a_202) | | | | | | | | | [removed: [63](#i1fc9d0e18c654199a6dadea9bc41997a_202)] [added: [65](#i1fc9d0e18c654199a6dadea9bc41997a_202)] | | |

| | | | | | | | | | [2. Regulatory Matters](#i1fc9d0e18c654199a6dadea9bc41997a_250) | | | | | | | | | [removed: [68](#i1fc9d0e18c654199a6dadea9bc41997a_250)] [added: [71](#i1fc9d0e18c654199a6dadea9bc41997a_250)] | | |

| | | | | | | | | | [3. Property, Plant and Equipment](#i1fc9d0e18c654199a6dadea9bc41997a_253) | | | | | | | | | [removed: [71](#i1fc9d0e18c654199a6dadea9bc41997a_253)] [added: [74](#i1fc9d0e18c654199a6dadea9bc41997a_253)] | | |

| | | | | | | | | | [4. Jointly-owned Electric Utility Plant](#i1fc9d0e18c654199a6dadea9bc41997a_256) | | | | | | | | | [removed: [73](#i1fc9d0e18c654199a6dadea9bc41997a_256)] [added: [75](#i1fc9d0e18c654199a6dadea9bc41997a_256)] | | |

| | | | | | | | | | [5. Receivables](#i1fc9d0e18c654199a6dadea9bc41997a_259) | | | | | | | | | [removed: [73](#i1fc9d0e18c654199a6dadea9bc41997a_259)] [added: [76](#i1fc9d0e18c654199a6dadea9bc41997a_259)] | | |

| | | | | | | | | | [6. Investments](#i1fc9d0e18c654199a6dadea9bc41997a_268) | | | | | | | | | [removed: [74](#i1fc9d0e18c654199a6dadea9bc41997a_268)] [added: [77](#i1fc9d0e18c654199a6dadea9bc41997a_268)] | | |

| | | | | | | | | | [7. Common Equity](#i1fc9d0e18c654199a6dadea9bc41997a_274) | | | | | | | | | [removed: [75](#i1fc9d0e18c654199a6dadea9bc41997a_274)] [added: [77](#i1fc9d0e18c654199a6dadea9bc41997a_274)] | | |

| | | | | | | | | | [removed: [9.] [added: [8](#i1fc9d0e18c654199a6dadea9bc41997a_280)[.] Debt](#i1fc9d0e18c654199a6dadea9bc41997a_280) | | | | | | | | | [removed: [75](#i1fc9d0e18c654199a6dadea9bc41997a_280)] [added: [78](#i1fc9d0e18c654199a6dadea9bc41997a_280)] | | |

| | | | | | | | | | [removed: [10.] [added: [9](#i1fc9d0e18c654199a6dadea9bc41997a_292)[.] Leases](#i1fc9d0e18c654199a6dadea9bc41997a_292) | | | | | | | | | [removed: [78](#i1fc9d0e18c654199a6dadea9bc41997a_292)] [added: [81](#i1fc9d0e18c654199a6dadea9bc41997a_292)] | | |

| | | | | | | | | | [removed: [11.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_295)[0](#i1fc9d0e18c654199a6dadea9bc41997a_295)[.] Revenues](#i1fc9d0e18c654199a6dadea9bc41997a_295) | | | | | | | | | [removed: [79](#i1fc9d0e18c654199a6dadea9bc41997a_295)] [added: [82](#i1fc9d0e18c654199a6dadea9bc41997a_295)] | | |

| | | | | | | | | | [removed: [12.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_298)[1](#i1fc9d0e18c654199a6dadea9bc41997a_298)[.] Income Taxes](#i1fc9d0e18c654199a6dadea9bc41997a_298) | | | | | | | | | [removed: [80](#i1fc9d0e18c654199a6dadea9bc41997a_298)] [added: [83](#i1fc9d0e18c654199a6dadea9bc41997a_298)] | | |

| | | | | | | | | | [removed: [13.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_301)[2](#i1fc9d0e18c654199a6dadea9bc41997a_301)[.] Benefit Plans](#i1fc9d0e18c654199a6dadea9bc41997a_301) | | | | | | | | | [removed: [82](#i1fc9d0e18c654199a6dadea9bc41997a_301)] [added: [85](#i1fc9d0e18c654199a6dadea9bc41997a_301)] | | |

| | | | | | | | | | [removed: [14.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_313)[3](#i1fc9d0e18c654199a6dadea9bc41997a_313)[.] Asset Retirement Obligations](#i1fc9d0e18c654199a6dadea9bc41997a_313) | | | | | | | | | [removed: [91](#i1fc9d0e18c654199a6dadea9bc41997a_313)] [added: [94](#i1fc9d0e18c654199a6dadea9bc41997a_313)] | | |

| | | | | | | | | | [removed: [15.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_316)[4](#i1fc9d0e18c654199a6dadea9bc41997a_316)[.] Derivative Instruments](#i1fc9d0e18c654199a6dadea9bc41997a_316) | | | | | | | | | [removed: [91](#i1fc9d0e18c654199a6dadea9bc41997a_316)] [added: [94](#i1fc9d0e18c654199a6dadea9bc41997a_316)] | | |

| | | | | | | | | | [removed: [16.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_322)[5](#i1fc9d0e18c654199a6dadea9bc41997a_322)[.] Fair Value Measurements](#i1fc9d0e18c654199a6dadea9bc41997a_322) | | | | | | | | | [removed: [92](#i1fc9d0e18c654199a6dadea9bc41997a_322)] [added: [95](#i1fc9d0e18c654199a6dadea9bc41997a_322)] | | |

| | | | | | | | | | [removed: [17.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_328)[6](#i1fc9d0e18c654199a6dadea9bc41997a_328)[.] Commitments and Contingencies](#i1fc9d0e18c654199a6dadea9bc41997a_328) | | | | | | | | | [removed: [94](#i1fc9d0e18c654199a6dadea9bc41997a_328)] [added: [97](#i1fc9d0e18c654199a6dadea9bc41997a_328)] | | |

| | | | | | | | | | [removed: [18.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_352)[7](#i1fc9d0e18c654199a6dadea9bc41997a_352)[.] Segments of Business](#i1fc9d0e18c654199a6dadea9bc41997a_352) | | | | | | | | | [removed: [97](#i1fc9d0e18c654199a6dadea9bc41997a_352)] [added: [100](#i1fc9d0e18c654199a6dadea9bc41997a_352)] | | |

| | | | | | | | | | [removed: [19.] [added: [1](#i1fc9d0e18c654199a6dadea9bc41997a_355)[8](#i1fc9d0e18c654199a6dadea9bc41997a_355)[.] Related Parties](#i1fc9d0e18c654199a6dadea9bc41997a_355) | | | | | | | | | [removed: [99](#i1fc9d0e18c654199a6dadea9bc41997a_355)] [added: [101](#i1fc9d0e18c654199a6dadea9bc41997a_355)] | | |

| FTR | | | Financial transmission right | | | WPL | | | Wisconsin Power and Light Company | | |

- the impact of IPL’s retail electric base rate moratorium;

- the ability and cost to provide sufficient generation and the ability of ITC and ATC to provide sufficient transmission capacity for potential load growth, including significant new commercial or industrial customers, such as data centers;

- the ability of potential large load growth customers to timely construct new facilities, as well as the resulting higher system load demand by expected levels and timeframes;

- the ability to achieve the expected level of tax benefits based on tax guidelines, timely in-service dates, compliance with prevailing wage and apprenticeship requirements, project costs and the level of electricity output generated by qualifying generating facilities, and the ability to efficiently utilize the renewable generation and energy storage project tax benefits to achieve IPL’s authorized rate of return and for the benefit of IPL’s and WPL’s customers;

- the timely development of technologies, innovations and advancements to provide cost effective alternatives to traditional energy sources;

| | | | | | | | | | [8. Preferred Stock](#i1fc9d0e18c654199a6dadea9bc41997a_277) | | | | | | | | | [75](#i1fc9d0e18c654199a6dadea9bc41997a_277) | | |

| FTR | | | Financial transmission right | | | Whiting Petroleum | | | Whiting Petroleum Corporation | | |

- the ability to obtain deferral treatment for the recovery of and a return on prudently incurred costs in between rate reviews;

- WPL’s ability to obtain adequate and timely rate relief to allow for the recovery of and/or the return on costs of solar generation projects that exceed initial cost estimates;

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | 22 | | | | | |

[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

Cybersecurity risks are identified [added: as key risks] through the enterprise risk management (ERM) [removed: program as key risks we face.][added: program.]

These risks could include use of malicious code, employee theft or misuse, advanced persistent threats, vulnerabilities, fraud attempts, and phishing attacks that could cause, among others, an [added: operations or] information technology system failure, or breach or loss of sensitive information.

We maintain a cybersecurity program that includes development and implementation of policies, procedures and tools designed to help ensure availability of critical [added: operations,] information technology and telecommunication systems and safeguard sensitive information.

The cybersecurity program is assessed against industry standards, including [removed: the] [added: certain] Center for Internet Security critical security controls.

We also periodically collaborate with [added: federal and state] law enforcement experts, external assessors, consultants, industry peers and other third parties in connection with understanding market and threat conditions used to identify, assess and mitigate cybersecurity risks.

- [added: operations,] information technology and telecommunication systems implemented with segmentation and multiple levels of access controls;

Our cybersecurity program is overseen by our Senior Vice President and CIO, who has nearly [removed: two] [added: four] decades of experience in information technology, [added: including two decades as a CIO,] having previously held CIO roles with other organizations, as well as experience in the utility sector.

Management, including the CIO, provides reports approximately quarterly to the Board regarding risks, threats, the threat landscape, assessments of and improvements to the cybersecurity [removed: program] [added: program,] and internal response preparedness.

| | | | 23 | | | | | |

| | | | 21 | | | | | |

Electric - At December 31, [removed: 2023,] [added: 2024,] IPL’s and WPL’s facilities by primary fuel type were as follows:

| Marshalltown Generating Station (Units 1-3); Marshalltown, IA | | | | | | | | | | | | 2017 | | | | | | | | | | | | | | | | | | [removed: 656] [added: 652] | | |

| Emery Generating Station (Units 1-3); Mason City, IA | | | | | | | | | | | | 2004 | | | | | | | | | | | | | | | | | | [removed: 533] [added: 531] | | |

| Marshalltown Combustion Turbines (Units 1-3); Marshalltown, IA | | | | | | | | | | | | 1978 | | | | | | | | | | | | | | | | | | [removed: 162] [added: 105] | | |

| Burlington Generating Station (Unit 1); Burlington, IA | | | | | | | | | | | | 1968 | | | | | | | | | | | | | | | | | | [removed: 160] [added: 131] | | |

| Prairie Creek Generating Station (Unit 4); Cedar Rapids, IA | | | | | | | | | | | | 1967 | | | | | | | | | | | | | | | | | | [removed: 114] [added: 126] | | |

| Burlington Combustion Turbines (Units 1-4); Burlington, IA | | | | | | | | | | | | 1994-1996 | | | | | | | | | | | | | | | | | | [removed: 36] [added: 37] | | |

| Total Gas | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 1,661] [added: 1,582] | | |

| Ottumwa Generating Station (Unit 1); Ottumwa, IA (b) | | | | | | | | | | | | 1981 | | | | | | | | | | | | | | | | | | [removed: 348] [added: 339] | | |

| George Neal Generating Station (Unit 4); Sioux City, IA (c) | | | | | | | | | | | | 1979 | | | | | | | | | | | | | | | | | | [removed: 166] [added: 167] | | |

| George Neal Generating Station (Unit 3); Sioux City, IA (d) | | | | | | | | | | | | 1975 | | | | | | | | | | | | | | | | | | [removed: 143] [added: 140] | | |

| Prairie Creek Generating Station (Units 1 and 3); Cedar Rapids, IA | | | | | | | | | | | | 1958-1997 | | | | | | | | | | | | | | | | | | [removed: 36] [added: 30] | | |

| Total Coal | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 723] [added: 706] | | |

| Lime Creek Combustion Turbines (Units 1-2); Mason City, IA | | | | | | | | | | | | 1991 | | | | | | | | | | | | | | | | | | [removed: 71] [added: 70] | | |

| Total Oil | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 71] [added: 70] | | |

| [removed: Dubuque Solar Facility;] [added: Dubuque;] Dubuque, IA | | | | | | | | | | | | 2017 | | | | | | | | | | | | | | | | | | 5 | | |

| [removed: Marshalltown Solar Facility;] [added: Marshalltown;] Marshalltown, IA | | | | | | | | | | | | 2020 | | | | | | | | | | | | | | | | | | 3 | | |

| Total Solar | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 8] [added: 419] | | |

| [removed: Battery] [added: Energy] Storage; various locations in IA | | | | | | | | | | | | 2019-2023 | | | | | | | | | | | | | | | | | | 9 | | |

| Total [removed: Battery] [added: Energy] Storage | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 9 | | |

| Total capacity | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 3,774] [added: 4,088] | | |

| Riverside Energy Center (Units 1-3); Beloit, WI | | | | | | | | | | | | 2004 | | | | | | | | | | | | | | | | | | [removed: 530] [added: 536] | | |

| West Riverside Energy Center (Units 1-3); Beloit, WI (f) | | | | | | | | | | | | 2020 | | | | | | | | | | | | | | | | | | [removed: 508] [added: 387] | | |

| Neenah Energy Facility (Units 1-2); Neenah, WI | | | | | | | | | | | | 2000 | | | | | | | | | | | | | | | | | | [removed: 299] [added: 292] | | |

| South Fond du Lac Combustion Turbines (2 Units); Fond du Lac, WI (g) | | | | | | | | | | | | 1994 | | | | | | | | | | | | | | | | | | [removed: 164] [added: 163] | | |

| Total Gas | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 1,501] [added: 1,378] | | |

| Columbia Energy Center (Units 1-2); Portage, WI (i) | | | | | | | | | | | | 1975-1978 | | | | | | | | | | | | | | | | | | [removed: 606] [added: 598] | | |

| Total Coal | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [removed: 1,012] [added: 1,004] | | |

| Wood [removed: County Solar Facility,] [added: County,] Wood Co., WI | | | | | | | | | | | | 2022 | | | | | | | | | | | | | | | | | | 150 | | |

| Onion [removed: River Solar Facility,] [added: River,] Sheboygan Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 150 | | |

| [removed: Springfield Solar Facility,] [added: Springfield,] Dodge Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 100 | | |

| [removed: Wautoma Solar Facility,] [added: Wautoma,] Waushara Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 99 | | |

| Crawfish [removed: River Solar Facility,] [added: River,] Jefferson Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 75 | | |

| [removed: Paddock Solar Facility,] [added: Paddock,] Rock Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 65 | | |

| Bear [removed: Creek Solar Facility,] [added: Creek,] Richland Co., WI | | | | | | | | | | | | 2022 | | | | | | | | | | | | | | | | | | 50 | | |

| North [removed: Rock Solar Facility,] [added: Rock,] Rock Co., WI | | | | | | | | | | | | 2022 | | | | | | | | | | | | | | | | | | 50 | | |

| [removed: Albany Solar Facility,] [added: Albany,] Green Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 50 | | |

| Beaver [removed: Dam Solar Facility,] [added: Dam,] Dodge Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 50 | | |

| [removed: Cassville Solar Facility,] [added: Cassville,] Grant Co., WI | | | | | | | | | | | | 2023 | | | | | | | | | | | | | | | | | | 50 | | |

| West [removed: Riverside Solar Facility,] [added: Riverside,] Beloit, WI (f) | | | | | | | | | | | | 2021 | | | | | | | | | | | | | | | | | | [removed: 3] [added: 2] | | |

| Pleasant Creek (Units 1-2), Linn Co., IA | | | | | | | | | | | | 2024 | | | | | | | | | | | | | | | | | | 200 | | |

| Wever; Lee Co., IA | | | | | | | | | | | | 2024 | | | | | | | | | | | | | | | | | | 150 | | |

| Creston; Union Co., IA | | | | | | | | | | | | 2024 | | | | | | | | | | | | | | | | | | 50 | | |

| Customer-hosted and Community Solar; various locations in IA | | | | | | | | | | | | 2024 | | | | | | | | | | | | | | | | | | 11 | | |

| Grant County, Grant Co., WI | | | | | | | | | | | | 2024 | | | | | | | | | | | | | | | | | | 200 | | |

| Total Energy Storage | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 9 | | |

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[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

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| | | | 23 | | | | | |

| [removed: John O. Larsen] [added: Lisa M. Barton] | | | | | | [removed: 60] [added: 59] | | | | | | Alliant Energy | | | | | | [removed: Mr. Larsen] [added: Ms. Barton] has served as [removed: a director since February 2019,] [added: President] and [removed: as] [added: Chief] Executive [removed: Chairman] [added: Officer (CEO)] and [removed: Chairman of the Board] [added: as a director] since January 2024. [removed: He] [added: She] previously served as [removed: Chair of the Board] [added: President] and Chief [removed: Executive] [added: Operating] Officer [removed: (CEO)] [added: (COO)] since February 2023, as [removed: Chair of the Board,] [added: Executive Vice] President [added: (VP)] and [removed: CEO] [added: COO of American Electric Power Company, Inc. (AEP)] from [removed: July 2019] [added: January 2021] to [removed: February 2023,] [added: November 2022,] and as [removed: President and Chief Operating Officer (COO)] [added: Executive VP - Utilities of AEP] from January [removed: 2019] [added: 2020] to [removed: July 2019.] [added: December 2020.] | | |

| Robert J. Durian | | | | | | [removed: 53] [added: 54] | | | | | | Alliant Energy, IPL and WPL | | | | | | Mr. Durian has served as Executive VP and Chief Financial Officer (CFO) since February 2020. He previously served as Senior VP and CFO since February [removed: 2019; and as Senior VP, CFO and Treasurer from January 2018 to February] 2019. | | |

| David A. de Leon | | | | | | [removed: 61] [added: 62] | | | | | | Alliant Energy and IPL | | | | | | Mr. de Leon has served as Senior VP since January 2019. | | |

| Mayuri N. Farlinger | | | | | | [removed: 41] [added: 42] | | | | | | Alliant Energy and WPL | | | | | | Ms. Farlinger has served as Vice President since January 2022. She previously served as Director of Operations from January 2020 to December [removed: 2021, as Director of Revenue Management from February 2019 to January 2020, and as Manager - Customer Support Center, Billing Integrity from May 2018 to February 2019.] [added: 2021.] | | |

| | | | | | | | | | | | | IPL | | | | | | Ms. Farlinger has served as [removed: Vice] President since [removed: January 2022. She was selected to become President of IPL effective] May [removed: 1,] 2024. | | |

| Benjamin M. Bilitz | | | | | | [removed: 48] [added: 50] | | | | | | Alliant Energy, IPL and WPL | | | | | | Mr. Bilitz has served as Chief Accounting Officer and Controller since December 2016. | | |

| | | | 26 | | | | | |

| Dylan M. Syse | | | | | | 39 | | | | | | Alliant Energy, IPL and WPL | | | | | | Mr. Syse was selected to become Chief Accounting Officer and Controller effective March 2, 2025. He has served as Assistant Controller since November 2021, as Manager - Accounting and Reporting from May 2020 to November 2021, and as Manager - Accounting from May 2018 to April 2020. | | |

| | | | | | | | | | | | | IPL and WPL | | | | | | Mr. Larsen has served as a director since February 2019, and as Executive Chairman and Chairman of the Board since January 2024. He previously served as Chair of the Board since July 2019, and as CEO from January 2019 to February 2023. | | |

| Lisa M. Barton | | | | | | 58 | | | | | | Alliant Energy | | | | | | Ms. Barton has served as President and CEO and as a director since January 2024. She previously served as President and COO since February 2023, as Executive Vice President (VP) and COO of American Electric Power Company, Inc. (AEP) from January 2021 to November 2022, as Executive VP - Utilities of AEP from January 2020 to December 2020, and as Executive VP - Transmission of AEP from 2011 to 2019. | | |

| | | | 25 | | | | | |

| Terry L. Kouba | | | | | | 65 | | | | | | Alliant Energy and WPL | | | | | | Mr. Kouba has served as Senior VP since January 2019. Mr. Kouba plans to retire effective May 1, 2024. | | |

| | | | | | | | | | | | | IPL | | | | | | Mr. Kouba has served as President since January 2019. | | |

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, [removed: 2023] [added: 2024] was [removed: $51.30.][added: $59.14.]

Shareowners - At December 31, [removed: 2023,] [added: 2024,] there were [removed: 20,547] [added: 19,293] holders of record of Alliant Energy’s common stock, including holders through Alliant Energy’s Shareowner Direct Plan.

Dividends - In [removed: November 2023,] [added: October 2024,] Alliant Energy announced an increase in its targeted [removed: 2024] [added: 2025] annual common stock dividend to [removed: $1.92] [added: $2.03] per share, which is equivalent to a quarterly rate of [removed: $0.48] [added: $0.5075] per share, beginning with the February [removed: 2024] [added: 2025] dividend payment.

The timing and amount of future dividends is subject to [removed: an approved] [added: approval of quarterly] dividend [removed: declaration] [added: declarations] from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

Common Stock Repurchases - A summary of Alliant Energy common stock repurchases for the quarter ended December 31, [removed: 2023] [added: 2024] was as follows:

| October 1 to October 31 | | | | | | 6,487 | | | | | | $59.67 | | | | | | — | | | | | | N/A | | |

| November 1 to November 30 | | | | | | 2,933 | | | | | | 62.65 | | | | | | — | | | | | | N/A | | |

| December 1 to December 31 | | | | | | 19 | | | | | | 59.99 | | | | | | — | | | | | | N/A | | |

| | | | | | | 9,439 | | | | | | 60.60 | | | | | | — | | | | | | | | |

| October 1 to October 31 | | | | | | 5,338 | | | | | | $49.75 | | | | | | — | | | | | | N/A | | |

| November 1 to November 30 | | | | | | 3,685 | | | | | | 49.32 | | | | | | — | | | | | | N/A | | |

| December 1 to December 31 | | | | | | 25 | | | | | | 51.16 | | | | | | — | | | | | | N/A | | |

| | | | | | | 9,048 | | | | | | 49.58 | | | | | | — | | | | | | | | |

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[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

We have audited the accompanying consolidated balance sheets of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, [removed: 2023] [added: 2024] and [removed: 2022,] [added: 2023,] the related consolidated statements of income, equity, and cash flows, for each of the three years in the period ended December 31, [removed: 2023,] [added: 2024,] 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, [removed: 2023] [added: 2024] and [removed: 2022,] [added: 2023,] and the results of its operations and its cash flows for each of the three years in the period ended December 31, [removed: 2023,] [added: 2024,] 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, [removed: 2023,] [added: 2024,] 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 [removed: 16, 2024,] [added: 21, 2025,] expressed an unqualified opinion on the Company’s internal control over financial reporting.

Regulatory Accounting - Impact of rate regulation on the financial statements - Refer to Notes [removed: 1, 2,] [added: 1] and [removed: 3] [added: 2] to the financial statements

Regulatory assets [added: generally] represent incurred costs that have been deferred and are probable of recovery in future customer rates.

Regulatory liabilities [added: generally] represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred.

We evaluated the external information and assessed whether there are matters in such information that would be contradictory to management’s assertion of probability of recovery of certain regulatory assets or refund of regulatory [removed: liabilities.][added: liabilities, or impact other recorded balances.]

[removed: February 16, 2024][added: | 2024: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |]

| | | | [removed: 2023] [added: 2024] | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | |

| Electric utility | | | [removed: $3,345] [added: $3,372] | | | | | | [removed: $3,421] [added: $3,345] | | | | | | [removed: $3,081] [added: $3,421] | | |

| Gas utility | | | [removed: 540] [added: 465] | | | | | | [removed: 642] [added: 540] | | | | | | [removed: 456] [added: 642] | | |

| Other utility | | | [removed: 52] [added: 54] | | | | | | [removed: 49] [added: 52] | | | | | | 49 | | |

| Non-utility | | | 90 | | | | | | [removed: 93] [added: 90] | | | | | | [removed: 83] [added: 93] | | |

| Total revenues | | | [removed: 4,027] [added: 3,981] | | | | | | [removed: 4,205] [added: 4,027] | | | | | | [removed: 3,669] [added: 4,205] | | |

| Electric production fuel and purchased power | | | [removed: 736] [added: 628] | | | | | | [removed: 830] [added: 736] | | | | | | [removed: 642] [added: 830] | | |

| Electric transmission service | | | [removed: 583] [added: 613] | | | | | | [removed: 573] [added: 583] | | | | | | [removed: 537] [added: 573] | | |

| Cost of gas sold | | | [removed: 299] [added: 224] | | | | | | [removed: 389] [added: 299] | | | | | | [removed: 258] [added: 389] | | |

| Other operation and [removed: maintenance] [added: maintenance:] | | | [removed: 675] | | | | | | [removed: 704] | | | | | | [removed: 676] | | |

| Depreciation and amortization | | | [removed: 676] [added: 772] | | | | | | [removed: 671] [added: 676] | | | | | | [removed: 657] [added: 671] | | |

| Taxes other than income taxes | | | [removed: 115] [added: 122] | | | | | | [removed: 110] [added: 115] | | | | | | [removed: 104] [added: 110] | | |

| Total operating expenses | | | [removed: 3,084] [added: 3,095] | | | | | | [removed: 3,277] [added: 3,084] | | | | | | [removed: 2,874] [added: 3,277] | | |

| Operating income | | | [removed: 943] [added: 886] | | | | | | [removed: 928] [added: 943] | | | | | | [removed: 795] [added: 928] | | |

| Interest expense | | | [removed: 394] [added: 449] | | | | | | [removed: 325] [added: 394] | | | | | | [removed: 277] [added: 325] | | |

| Equity income from unconsolidated investments, net | | | (61) | | | | | | [removed: (51)] [added: (61)] | | | | | | [removed: (62)] [added: (51)] | | |

| Allowance for funds used during construction | | | [removed: (100)] [added: (75)] | | | | | | [removed: (60)] [added: (100)] | | | | | | [removed: (25)] [added: (60)] | | |

| Other | | | [removed: 3] [added: (3)] | | | | | | [removed: 6] [added: 3] | | | | | | [removed: 5] [added: 6] | | |

| Total other (income) and deductions | | | [removed: 236] [added: 310] | | | | | | [removed: 220] [added: 236] | | | | | | [removed: 195] [added: 220] | | |

| Income before income taxes | | | [removed: 707] [added: 576] | | | | | | [removed: 708] [added: 707] | | | | | | [removed: 600] [added: 708] | | |

| [removed: Income] [added: Income] tax expense [removed: (benefit)] [added: (benefit)] | | | [removed: 4] [added: (58)] | | | | | | [removed: 22] [added: 60] | | | | | | [removed: (74)] [added: 2] | | | [added: | | | 2 | | | | | | 4 | | |]

| Net income attributable to Alliant Energy common shareowners | | | [removed: $703] [added: $690] | | | | | | [removed: $686] [added: $703] | | | | | | [removed: $659] [added: $686] | | |

| Basic | | | [removed: 253.0] [added: 256.5] | | | | | | [removed: 250.9] [added: 253.0] | | | | | | [removed: 250.2] [added: 250.9] | | |

| Diluted | | | [removed: 253.3] [added: 256.8] | | | | | | [removed: 251.2] [added: 253.3] | | | | | | [removed: 250.7] [added: 251.2] | | |

| Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted) | | | [removed: $2.78] [added: $2.69] | | | | | | [removed: $2.73] [added: $2.78] | | | | | | [removed: $2.63] [added: $2.73] | | |

| | | | [removed: 2023] [added: 2024] | | | | | | [added: 2023 | | | | | |] 2022 | | |

| Cash and cash equivalents | | | [removed: $62] [added: $81] | | | | | | [removed: $20] [added: $62] | | |

| Accounts receivable, less allowance for expected credit losses | | | [removed: 475] [added: 427] | | | | | | [removed: 516] [added: 475] | | |

| Production fuel, at weighted average cost | | | [removed: 62] [added: 54] | | | | | | [removed: 53] [added: 62] | | |

| Gas stored underground, at weighted average cost | | | [removed: 79] [added: 55] | | | | | | [removed: 132] [added: 79] | | |

| Materials and supplies, at weighted average cost | | | [removed: 202] [added: 186] | | | | | | [removed: 140] [added: 202] | | |

| Regulatory assets | | | [removed: 232] [added: 210] | | | | | | [removed: 166] [added: 232] | | |

February 21, 2025

| Asset valuation charge for IPL’s Lansing Generating Station | | | 60 | | | | | | — | | | | | | — | | |

| Other | | | 676 | | | | | | 675 | | | | | | 704 | | |

| Depreciation and amortization | | | 772 | | | | | | 676 | | | | | | 671 | | |

| Asset valuation charge for IPL’s Lansing Generating Station | | | 60 | | | | | | — | | | | | | — | | |

| Ending balance | | | $3 | | | | | | $3,060 | | | | | | $3,954 | | | | | | $1 | | | | | | ($14) | | | | | | | | | | | | | | | | | | $7,004 | | |

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

Regulatory assets generally represent incurred costs that have been deferred and are probable of recovery in future customer rates.

Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred.

We evaluated the external information and assessed whether there are matters in such information that would be contradictory to management’s assertion of probability of recovery of certain regulatory assets or refund of regulatory liabilities, or impact other recorded balances.

February 21, 2025

| Asset valuation charge for IPL’s Lansing Generating Station | | | 60 | | | | | | — | | | | | | — | | |

| Other | | | 358 | | | | | | 353 | | | | | | 369 | | |

| | | | 2024 | | | | | | 2023 | | |

| Commercial paper | | | 50 | | | | | | — | | |

| Accounts payable to associated companies | | | 47 | | | | | | 51 | | |

| Commitments and contingencies ([Note 1](#i1fc9d0e18c654199a6dadea9bc41997a_328)[6](#i1fc9d0e18c654199a6dadea9bc41997a_328)) | | | | | | | | | | | |

| Asset valuation charge for IPL’s Lansing Generating Station | | | 60 | | | | | | — | | | | | | — | | |

| Cash receipts on sold receivables | | | 593 | | | | | | 453 | | | | | | 598 | | |

| Payments to retire long-term debt | | | (500) | | | | | | — | | | | | | — | | |

| Beneficial interest obtained in exchange for securitized accounts receivable | | | $163 | | | | | | $216 | | | | | | $185 | | |

| Beginning balance | | | $33 | | | | | | $2,807 | | | | | | $929 | | | | | | | | | | | | $3,769 | | |

| 2024: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Ending balance | | | $33 | | | | | | $3,212 | | | | | | $1,216 | | | | | | | | | | | | $4,461 | | |

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

Regulatory assets generally represent incurred costs that have been deferred and are probable of recovery in future customer rates.

Regulatory liabilities generally represent obligations to make refunds to customers or amounts collected in rates for which the costs have not yet been incurred.

We evaluated the external information and assessed whether there are matters in such information that would be contradictory to management’s assertion of probability of recovery of certain regulatory assets or refund of regulatory liabilities, or impact other recorded balances.

February 21, 2025

| Other | | | 8 | | | | | | (3) | | | | | | (1) | | |

| | | | 2024 | | | | | | 2023 | | |

| Other | | | 57 | | | | | | 43 | | |

| Other | | | 94 | | | | | | 89 | | |

| Commitments and contingencies ([Note 1](#i1fc9d0e18c654199a6dadea9bc41997a_328)[6](#i1fc9d0e18c654199a6dadea9bc41997a_328)) | | | | | | | | | | | |

| Other | | | (28) | | | | | | 12 | | | | | | 25 | | |

| Proceeds from sales of partial ownership interests in West Riverside | | | 123 | | | | | | 120 | | | | | | — | | |

| Other | | | (19) | | | | | | (47) | | | | | | (13) | | |

| Net change in commercial paper | | | (135) | | | | | | 28 | | | | | | 54 | | |

| Other | | | (14) | | | | | | (16) | | | | | | (9) | | |

| Cash (paid) received during the period for: | | | | | | | | | | | | | | | | | |

| | | | 44 | | | | | |

| | | | 45 | | | | | |

- We inspected minutes of the board of directors and other committees of the Company, regulatory orders and other filings with the regulatory agencies to identify evidence that may contradict management’s assertion regarding probability of abandonment or that may have an impact on the recorded balances.

| Net income | | | 703 | | | | | | 686 | | | | | | 674 | | |

| Preferred dividend requirements of Interstate Power and Light Company | | | — | | | | | | — | | | | | | 15 | | |

| | | | | | | | | | | | |

| Payments to redeem cumulative preferred stock of IPL | | | — | | | | | | — | | | | | | (200) | | |

| | | | Total Alliant Energy Common Equity | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| 2021: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Beginning balance | | | $2 | | | | | | $2,704 | | | | | | $2,994 | | | | | | ($1) | | | | | | ($11) | | | | | | $200 | | | | | | | | | | | | $5,888 | | |

| Redemption of IPL’s cumulative preferred stock | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (200) | | | | | | | | | | | | (200) | | |

| Other comprehensive income, net of tax | | | | | | | | | | | | | | | | | | | | | 1 | | | | | | | | | | | | | | | | | | | | | | | | 1 | | |

| Preferred dividend requirements | | | — | | | | | | — | | | | | | 15 | | |

| Materials and supplies | | | (39) | | | | | | (13) | | | | | | (7) | | |

| Payments to redeem cumulative preferred stock | | | — | | | | | | — | | | | | | (200) | | |

| | | | Total IPL Common Equity | | | | | | | | | | | | | | | | | | | | | | | | | | |

| | | | | | | | | | Additional | | | | | | | | | | | | Cumulative | | | | | | | | |

| 2021: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| Beginning balance | | | $33 | | | | | | $2,752 | | | | | | $979 | | | | | | $200 | | | | | | $3,964 | | |

| Net income available for common stock | | | | | | | | | | | | | | | 350 | | | | | | | | | | | | 350 | | |

| Redemption of cumulative preferred stock | | | | | | | | | | | | | | | | | | | | | (200) | | | | | | (200) | | |

| Net income available for common stock | | | | | | | | | | | | | | | 360 | | | | | | | | | | | | 360 | | |

| Ending balance | | | 33 | | | | | | 2,807 | | | | | | 968 | | | | | | — | | | | | | 3,808 | | |

| Other | | | (3) | | | | | | (1) | | | | | | 2 | | |

| Materials and supplies, at weighted average cost | | | 77 | | | | | | 54 | | |

| Other | | | 43 | | | | | | 60 | | |

| Other | | | 89 | | | | | | 73 | | |

| Equity component of allowance for funds used during construction | | | (59) | | | | | | (36) | | | | | | (11) | | |

| Other | | | 25 | | | | | | 21 | | | | | | 22 | | |

| Other | | | 29 | | | | | | (69) | | | | | | (48) | | |

| Other | | | (47) | | | | | | (13) | | | | | | (30) | | |

| Other | | | (16) | | | | | | (9) | | | | | | (12) | | |

| Beginning balance | | | $66 | | | | | | $1,459 | | | | | | $953 | | | | | | | | | | | | $2,478 | | |

The cash received from the transfer of renewable tax credits is recorded in cash flows from operating activities.

At December 31, 2023 and 2022, Alliant Energy’s restricted cash related to requirements in Sheboygan Power, LLC’s debt agreement.

component of rates collected from customers.

| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |

| IPL (Wind generation CWIP) | | | 6.9% | | | | | | 6.9% | | | | | | 7.0% | | |

operations are recorded to regulatory assets on the balance sheets.

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | 99 | | | | | |

[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

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, [removed: 2023] [added: 2024] 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, [removed: 2023.][added: 2024.]

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, [removed: 2023] [added: 2024] that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting.

Alliant Energy’s, IPL’s and WPL’s management assessed the effectiveness of their respective internal control over financial reporting as of December 31, [removed: 2023] [added: 2024] 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, [removed: 2023,] [added: 2024,] their respective internal control over financial reporting was effective.

We have audited the internal control over financial reporting of Alliant Energy Corporation and subsidiaries (the “Company”) as of December 31, [removed: 2023,] [added: 2024,] 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, [removed: 2023,] [added: 2024,] 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, [removed: 2023,] [added: 2024,] of the Company and our report dated February [removed: 16, 2024,] [added: 21, 2025,] expressed an unqualified opinion on the Company’s [removed: 2023] [added: 2024] financial statements.

| | | | 102 | | | | | |

February 21, 2025

| | | | 103 | | | | | |

| | | | 100 | | | | | |

February 16, 2024

| | | | 101 | | | | | |

During the quarter ended December 31, [removed: 2023,] [added: 2024,] no director or officer of Alliant Energy, IPL or WPL adopted or terminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement, as each term is defined in Item 408(a) of Regulation S-K.

The information required by Item 10 relating to directors and nominees for election of directors at the [removed: 2024] [added: 2025] 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, [added: insider trading policies] and [added: procedures, and] Alliant Energy’s, IPL’s and WPL’s Code of Conduct is incorporated herein by reference to the relevant information in the [removed: 2024] [added: 2025] 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.

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 [removed: 2024] [added: 2025] 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, [removed: 2023] [added: 2024] was as follows:

| | | | | | | Number of securities to be | | | | | | [removed: (B)] [added: Weighted-average] | | | | | | Number of securities remaining available | | |

| | | | | | | issued upon exercise of | | | | | | [removed: Weighted-average] exercise [added: price of] | | | | | | for future issuance under equity | | |

| | | | | | | outstanding options, | | | | | | [removed: price of] outstanding options, | | | | | | compensation plans (excluding | | |

(a)Represents performance [removed: shares, performance restricted stock units] [added: shares] and restricted stock units granted under the 2020 OIP, all of which are paid out in shares of Alliant Energy’s common stock.

The performance share [removed: and performance restricted stock unit] awards [removed: included in column (A) of the table] reflect an assumed payout at the maximum performance multiplier of 200%.

[removed: Also included are] [added: The] restricted stock units [removed: granted under the 2020 OIP, which] vest at the expiration of a three-year time-vesting period.

As of December 31, [removed: 2023,] [added: 2024,] there were performance shares and restricted stock units [removed: (performance- and time-vesting)] outstanding under the 2020 OIP, the only plan under which such equity awards are currently granted.

(c)As of December 31, [removed: 2023,] [added: 2024,] there were [removed: 379,006] [added: 372,116] shares of Alliant Energy’s common stock held under the DCP, which is described in [Note [removed: 13(c)](#i1fc9d0e18c654199a6dadea9bc41997a_310).][added: 1](#i1fc9d0e18c654199a6dadea9bc41997a_310)[2](#i1fc9d0e18c654199a6dadea9bc41997a_310)[(c)](#i1fc9d0e18c654199a6dadea9bc41997a_310).]

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 [removed: 2024] [added: 2025] 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.

| | | | | | | (A) | | | | | | (B) | | | | | | (C) | | |

| Equity compensation plans approved by shareowners | | | | | | 1,529,346 (a) | | | | | | $51.63 | | | | | | 7,107,084 (b) | | |

| | | | | | | 1,529,346 | | | | | | $51.63 | | | | | | 7,107,084 | | |

| | | | 104 | | | | | |

| | | | | | | (A) | | | | | | | | | | | | (C) | | |

| Equity compensation plans approved by shareowners | | | | | | 1,217,445 (a) | | | | | | $52.66 | | | | | | 7,714,741 (b) | | |

| | | | | | | 1,217,445 | | | | | | $52.66 | | | | | | 7,714,741 | | |

| | | | 102 | | | | | |

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 [removed: 2024] [added: 2025] 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 information required by Item 14 is incorporated herein by reference to the relevant information in the [removed: 2024] [added: 2025] Alliant Energy Proxy Statement, which will be filed with the SEC within 120 days after the end of Alliant Energy’s fiscal year.

| Audit fees | | | [removed: $1,468] [added: $1,412] | | | | | | [removed: 95%] [added: 96%] | | | | | | [removed: $1,351] [added: $1,468] | | | | | | 95% | | | | | | [removed: $1,228] [added: $1,242] | | | | | | 92% | | | | | | [removed: $1,096] [added: $1,228] | | | | | | [removed: 91%] [added: 92%] | | |

| Audit-related fees | | | [removed: 57] [added: 59] | | | | | | 4% | | | | | | [removed: 56] [added: 57] | | | | | | 4% | | | | | | 103 | | | | | | 8% | | | | | | [removed: 94] [added: 103] | | | | | | 8% | | |

| Tax fees | | | [removed: 8] [added: 3] | | | | | | [removed: 1%] [added: —%] | | | | | | [removed: 10] [added: 8] | | | | | | 1% | | | | | | [removed: 7] [added: 3] | | | | | | —% | | | | | | [removed: 8] [added: 7] | | | | | | [removed: 1%] [added: —%] | | |

| All other fees | | | [removed: 4] [added: 3] | | | | | | —% | | | | | | [removed: 7] [added: 4] | | | | | | —% | | | | | | [removed: 4] [added: 2] | | | | | | —% | | | | | | [removed: 5] [added: 4] | | | | | | —% | | |

| | | | [removed: $1,537] [added: $1,477] | | | | | | 100% | | | | | | [removed: $1,424] [added: $1,537] | | | | | | 100% | | | | | | [removed: $1,342] [added: $1,350] | | | | | | 100% | | | | | | [removed: $1,203] [added: $1,342] | | | | | | 100% | | |

IPL’s and WPL’s audit fees for [removed: 2023] [added: 2024] and [removed: 2022] [added: 2023] consisted of the respective fees billed for the audits of the financial statements of IPL and its subsidiaries and WPL and its subsidiaries, 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 [removed: 2023] [added: 2024] and [removed: 2022] [added: 2023] audits of Alliant Energy’s financial statements and effectiveness of internal controls over financial reporting.

IPL’s and WPL’s audit-related fees for [removed: 2023] [added: 2024] and [removed: 2022] [added: 2023] 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 [removed: 2023] [added: 2024 consisted of the fees billed for professional services rendered for tax compliance,] and [removed: 2022] [added: 2023] 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 [removed: 2023] [added: 2024] and [removed: 2022] [added: 2023] for IPL and WPL consisted of license fees for accounting research software products and seminars.

| | | | 2024 | | | | | | | | | | | | 2023 | | | | | | | | | | | | 2024 | | | | | | | | | | | | 2023 | | | | | | | | |

| | | | 2023 | | | | | | | | | | | | 2022 | | | | | | | | | | | | 2023 | | | | | | | | | | | | 2022 | | | | | | | | |

| | | | | | | | | |

| --- | --- | --- | --- | --- | --- | --- | --- | --- |

| | | | 103 | | | | | |

[Table of C](#i1fc9d0e18c654199a6dadea9bc41997a_7)[o](#i1fc9d0e18c654199a6dadea9bc41997a_7)[ntents](#i1fc9d0e18c654199a6dadea9bc41997a_7)

| CONDENSED STATEMENTS OF INCOME | | | [removed: 2023] [added: 2024] | | | | | | [removed: 2022] [added: 2023] | | | | | | [removed: 2021] [added: 2022] | | |

| Operating expenses | | | $3 | | | | | | [removed: $9] [added: $3] | | | | | | [removed: $5] [added: $9] | | |

| Operating loss | | | (3) | | | | | | [removed: (9)] [added: (3)] | | | | | | [removed: (5)] [added: (9)] | | |

| Equity earnings from consolidated subsidiaries | | | [removed: (742)] [added: (734)] | | | | | | [removed: (707)] [added: (742)] | | | | | | [removed: (664)] [added: (707)] | | |

| Interest expense | | | [removed: 34] [added: 40] | | | | | | [removed: 6] [added: 34] | | | | | | [removed: 1] [added: 6] | | |

| Other | | | [removed: 4] [added: 5] | | | | | | [removed: 1] [added: 4] | | | | | | 1 | | |

| Total other (income) and deductions | | | [removed: (704)] [added: (689)] | | | | | | [removed: (700)] [added: (704)] | | | | | | [removed: (662)] [added: (700)] | | |

| Income before income taxes | | | [removed: 701] [added: 686] | | | | | | [removed: 691] [added: 701] | | | | | | [removed: 657] [added: 691] | | |

| Income tax expense (benefit) | | | [removed: (5)] [added: (3)] | | | | | | [removed: 2] [added: (5)] | | | | | | [removed: (5)] [added: 2] | | |

| Net income | | | [removed: $706] [added: $689] | | | | | | [removed: $689] [added: $706] | | | | | | [removed: $662] [added: $689] | | |

| CONDENSED BALANCE SHEETS | | | [removed: 2023] [added: 2024] | | | | | | [removed: 2022] [added: 2023] | | |

| Notes receivable from affiliated companies | | | [removed: $96] [added: $103] | | | | | | [removed: $65] [added: $96] | | |

| Other | | | [removed: 1] [added: 2] | | | | | | 1 | | |

| Total current assets | | | [removed: 97] [added: 117] | | | | | | [removed: 66] [added: 97] | | |

| Investments in consolidated subsidiaries | | | [removed: 8,405] [added: 9,123] | | | | | | [removed: 7,801] [added: 8,405] | | |

| Other | | | [removed: 2] [added: 1] | | | | | | 2 | | |

| Total investments | | | [removed: 8,407] [added: 9,124] | | | | | | [removed: 7,803] [added: 8,407] | | |

| Other assets | | | [removed: 90] [added: 84] | | | | | | [removed: 97] [added: 90] | | |

| Total assets | | | [removed: $8,594] [added: $9,325] | | | | | | [removed: $7,966] [added: $8,594] | | |

| Notes payable to affiliated companies | | | [removed: 1,068] [added: 1,401] | | | | | | [removed: 1,318] [added: 1,068] | | |

| Total current liabilities | | | [removed: 1,235] [added: 2,307] | | | | | | [removed: 1,680] [added: 1,235] | | |

| Long-term debt, [removed: net] [added: net (excluding current portion)] | | | [removed: 568] [added: —] | | | | | | [removed: —] [added: 568] | | |

| Other liabilities | | | [removed: 2] [added: 3] | | | | | | [removed: 1] [added: 2] | | |

| Common stock and additional paid-in capital | | | [removed: 3,033] [added: 3,063] | | | | | | [removed: 2,780] [added: 3,033] | | |

| Retained earnings | | | [removed: 3,768] [added: 3,965] | | | | | | [removed: 3,518] [added: 3,768] | | |

| Accumulated other comprehensive income | | | 1 | | | | | | [removed: —] [added: 1] | | |

| Shares in deferred compensation trust | | | [removed: (13)] [added: (14)] | | | | | | (13) | | |

| Total common equity | | | [removed: 6,789] [added: 7,015] | | | | | | [removed: 6,285] [added: 6,789] | | |