COMMITMENTS AND CONTINGENCIES(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including IPL’s and WPL’s expansion of energy storage, improvements at the natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility, and repowering projects at WPL’s Bent Tree Energy Facility. At December 31, 2025, Alliant Energy’s, IPL’s, and WPL’s minimum future commitments in 2026 for these projects were $459 million, $302 million, and $155 million, respectively.(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At December 31, 2025, the related minimum future commitments, excluding amounts for purchased power commitments that do not have minimum thresholds but require payment when electricity is generated by the provider and amounts for future commitments to deliver power to electric customers that do not have current minimum thresholds but will be billed for requirements when power is provided, were as follows (in millions):
Alliant Energy20262027202820292030ThereafterTotal
Natural gas$271$191$163$145$103$245$1,118
Coal764228146
Other (a)571684317105
$404$249$199$149$106$262$1,369
IPL20262027202820292030ThereafterTotal
Natural gas$149$105$85$70$31$52$492
Coal34141058
Other (a)2422221648
$207$121$97$72$33$68$598
WPL20262027202820292030ThereafterTotal
Natural gas$122$86$78$75$72$193$626
Coal42281888
Other (a)25126
$189$115$96$75$72$193$740

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at December 31, 2025.
(c) Legal Proceedings - Alliant Energy, IPL and WPL are involved in legal and administrative proceedings before various courts and agencies with respect to matters arising in the ordinary course of business. Although unable to predict the outcome of these matters, Alliant Energy, IPL and WPL believe that appropriate reserves have been established and final disposition of these actions will not have a material effect on their financial condition or results of operations.(d) Guarantees and Indemnifications -
Whiting Petroleum Corporation (Whiting Petroleum) - In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum, an independent oil and gas company. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, has guaranteed the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations.

Whiting Petroleum previously completed bankruptcy proceedings and business combinations, which substantially reduce the likelihood that Alliant Energy will be obligated to make any payments under these guarantees. As of December 31, 2025, the currently known partnership obligations for the abandonment obligations are estimated at $92 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy is not currently aware of, nor does it currently expect to incur in the future, any material liabilities related to these guarantees and therefore has not recognized any material liabilities related to these guarantees as of December 31, 2025 and 2024.

Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $35 million as of December 31, 2025 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of December 31, 2025 and 2024.

Transfers of Renewable Tax Credits - IPL and WPL have entered into agreements to transfer renewable tax credits from certain wind, solar and energy storage facilities to other corporate taxpayers in exchange for cash. As of December 31, 2025, IPL and WPL provided indemnifications associated with $333 million and $266 million, respectively, of proceeds for renewable tax credits transferred to other corporate taxpayers in the event of an adverse interpretation of tax law, including whether the related tax credits meet the qualification requirements. Alliant Energy, IPL and WPL believe the likelihood of having to make any material cash payments under these indemnifications is remote.

Electric Transmission Infrastructure - IPL and WPL have entered into agreements with their respective electric transmission service providers related to the construction of infrastructure necessary for the data centers that are expected to be built in IPL’s and WPL’s service territories by certain of their customers. If these construction projects were to be terminated prior to the infrastructure being placed in service by the electric transmission service providers, then IPL or WPL must reimburse their respective provider for the related costs incurred to-date. As of December 31, 2025, IPL’s and WPL’s related guarantees were approximately $130 million and $55 million, respectively. Alliant Energy, IPL and WPL are not aware of any material liabilities related to these guarantees that it is probable that they will be obligated to pay and therefore have not recognized any material liabilities related to these guarantees as of December 31, 2025.
(e) Environmental Matters - Alliant Energy, IPL and WPL are subject to environmental regulations as a result of their current and past operations. These regulations are designed to protect public health and the environment and have resulted in compliance, remediation, containment and monitoring obligations, which are recorded as current and non-current environmental liabilities. Substantially all of the environmental liabilities recorded on the balance sheets relate to MGP sites.
Manufactured Gas Plant Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At December 31, 2025, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions):
Alliant EnergyIPLWPL
Range of estimated future costs$7 -$29$5 -$18$2 -$11
Current and non-current environmental liabilities$12$8$4

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential CAA issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed all of the requirements under the Consent Decree. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.

Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: CSAPR, Effluent Limitation Guidelines, CCR Rule, and various legislation and EPA regulations to monitor and regulate the emission of GHG, including the CAA.
(f) Credit Risk - IPL provides retail electric and gas services in Iowa and wholesale electric service in Illinois and Iowa. WPL provides retail electric and gas services and wholesale electric service in Wisconsin. The geographic concentration of IPL’s and WPL’s customers did not contribute significantly to overall credit risk exposure. In addition, as a result of a large customer base, IPL and WPL did not have any significant credit risk concentration for receivables arising from the sale of electricity or gas services.
Alliant Energy, IPL and WPL are subject to credit risk related to the ability of counterparties to meet their contractual payment obligations, including reimbursement of generation and transmission costs from large load growth customers, or the potential non-performance of counterparties to deliver contracted commodities and other goods or services at the contracted price. Credit policies are maintained to mitigate credit risk. These credit policies include evaluation of the financial condition of certain counterparties, use of credit risk-related contingent provisions in certain agreements that require credit support from counterparties not meeting specific criteria, different counterparties to reduce concentrations of credit risk and the use of standardized agreements that facilitate the netting of cash flows associated with certain counterparties. Based on these credit policies and different counterparties, as well as utility cost recovery mechanisms, it is unlikely that counterparty non-performance would have a material effect on financial condition or results of operations. However, there is no assurance that these items will protect against all losses from counterparty non-performance.

Refer to Notes 5(a) and 14 for details of allowances for expected credit losses and credit risk-related contingent features, respectively.
(g) Collective Bargaining Agreements - At December 31, 2025, employees covered by collective bargaining agreements represented 58%, 74% and 86% of total employees of Alliant Energy, IPL and WPL, respectively. In May 2026, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expires, representing 29% and 86% of total employees of Alliant Energy and WPL, respectively.

Historical Timeline

Fiscal YearFiled
2025Feb 20, 2026Showing above
2024Feb 21, 2025
2023Feb 16, 2024
2022Feb 24, 2023
2021Feb 18, 2022
2020Feb 19, 2021

About Commitments Disclosures

Commitments and contingencies disclosures catalog a company's off-balance-sheet obligations and legal exposures — purchase commitments, guarantee arrangements, pending litigation, and regulatory proceedings. These items represent potential future cash outflows that may not appear as liabilities on the balance sheet until they become probable and estimable.

Key signals: litigation reserves and disclosed loss ranges quantify management's estimate of legal exposure, but unquantified "reasonably possible" losses often represent the larger risk. Watch for changes in language around pending cases — shifts from "remote" to "reasonably possible" or increases in estimated loss ranges signal deteriorating outcomes. Unconditional purchase obligations and take-or-pay contracts create fixed cost structures that reduce operational flexibility. Guarantee arrangements for subsidiaries or joint ventures can create cascading obligations. Compare the total commitment schedule against projected free cash flow to assess whether the company can meet its obligations without additional financing.