Item 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

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Item 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions, except per share amounts)
Revenues:
Electric utility$853$791
Gas utility240205
Other utility1313
Non-utility2222
Total revenues1,1281,031
Operating expenses:
Electric production fuel and purchased power175163
Electric transmission service158152
Cost of gas sold137114
Other operation and maintenance160160
Depreciation and amortization211189
Taxes other than income taxes3031
Total operating expenses871809
Operating income257222
Other (income) and deductions:
Interest expense119107
Equity income from unconsolidated investments, net(13)(15)
Allowance for funds used during construction(18)(19)
Other31
Total other (income) and deductions9174
Income before income taxes166148
Income tax benefit(47)(10)
Net income attributable to Alliant Energy common shareowners$213$158
Weighted average number of common shares outstanding:
Basic256.8256.2
Diluted257.2256.5
Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)$0.83$0.62

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

March 31, 2025December 31, 2024
(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents$25$81
Accounts receivable, less allowance for expected credit losses361427
Production fuel, at weighted average cost5354
Gas stored underground, at weighted average cost1655
Materials and supplies, at weighted average cost196186
Regulatory assets172210
Other146171
Total current assets9691,184
Property, plant and equipment, net19,02218,701
Investments:
ATC Holdings426415
Other224224
Total investments650639
Other assets:
Regulatory assets2,1022,064
Deferred charges and other108126
Total other assets2,2102,190
Total assets$22,851$22,714
LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt$1,371$1,171
Commercial paper678558
Accounts payable405532
Regulatory liabilities10969
Other325385
Total current liabilities2,8882,715
Long-term debt, net (excluding current portion)8,5808,677
Other liabilities:
Deferred tax liabilities2,1472,188
Regulatory liabilities974959
Pension and other benefit obligations210224
Other959947
Total other liabilities4,2904,318
Commitments and contingencies (Note 12)
Equity:
Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 256,876,299 and 256,690,222 shares outstanding33
Additional paid-in capital3,0663,060
Retained earnings4,0373,954
Accumulated other comprehensive income—1
Shares in deferred compensation trust - 347,775 and 372,116 shares at a weighted average cost of $37.17 and $36.56 per share(13)(14)
Total Alliant Energy Corporation common equity7,0937,004
Total liabilities and equity$22,851$22,714

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions)
Cash flows from operating activities:
Net income$213$158
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization211189
Deferred tax benefit and tax credits(51)(12)
Other1(6)
Other changes in assets and liabilities:
Accounts receivable(128)(116)
Gas stored underground3927
Derivative assets630
Regulatory assets(12)35
Accounts payable(45)12
Regulatory liabilities53(14)
Other(38)4
Net cash flows from operating activities249307
Cash flows used for investing activities:
Construction and acquisition expenditures:
Utility business(554)(478)
Other(28)(32)
Cash receipts on sold receivables192155
Other(14)2
Net cash flows used for investing activities(404)(353)
Cash flows from financing activities:
Common stock dividends(130)(123)
Proceeds from issuance of long-term debt—597
Payments to retire long-term debt—(300)
Net change in commercial paper220(141)
Other9(15)
Net cash flows from financing activities9918
Net decrease in cash, cash equivalents and restricted cash(56)(28)
Cash, cash equivalents and restricted cash at beginning of period8163
Cash, cash equivalents and restricted cash at end of period$25$35
Supplemental cash flows information:
Cash paid during the period for:
Interest($139)($97)
Income taxes, net$—($2)
Significant non-cash investing and financing activities:
Accrued capital expenditures$144$204
Beneficial interest obtained in exchange for securitized accounts receivable$86$184

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions)
Revenues:
Electric utility$430$392
Gas utility118108
Steam and other1213
Total revenues560513
Operating expenses:
Electric production fuel and purchased power6767
Electric transmission service108103
Cost of gas sold6560
Other operation and maintenance8286
Depreciation and amortization11596
Taxes other than income taxes1516
Total operating expenses452428
Operating income10885
Other (income) and deductions:
Interest expense4742
Allowance for funds used during construction(9)(10)
Total other (income) and deductions3832
Income before income taxes7053
Income tax benefit(40)(10)
Net income$110$63

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of IPL’s common stock outstanding during the periods presented.

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

March 31, 2025December 31, 2024
(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents$12$29
Accounts receivable, less allowance for expected credit losses112192
Production fuel, at weighted average cost2730
Gas stored underground, at weighted average cost525
Materials and supplies, at weighted average cost121113
Regulatory assets7177
Other4443
Total current assets392509
Property, plant and equipment, net9,5849,336
Other assets:
Regulatory assets1,5221,509
Deferred charges and other4253
Total other assets1,5641,562
Total assets$11,540$11,407
LIABILITIES AND EQUITY
Current liabilities:
Current maturities of long-term debt$300$300
Commercial paper10950
Accounts payable193263
Accounts payable to associated companies3947
Accrued taxes7877
Accrued interest3848
Regulatory liabilities7654
Other7289
Total current liabilities905928
Long-term debt, net (excluding current portion)3,8913,790
Other liabilities:
Deferred tax liabilities1,1711,179
Regulatory liabilities485492
Pension and other benefit obligations4546
Other516511
Total other liabilities2,2172,228
Commitments and contingencies (Note 12)
Equity:
Interstate Power and Light Company common equity:
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding3333
Additional paid-in capital3,2573,212
Retained earnings1,2371,216
Total Interstate Power and Light Company common equity4,5274,461
Total liabilities and equity$11,540$11,407

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions)
Cash flows from operating activities:
Net income$110$63
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization11596
Deferred tax benefit and tax credits(30)(5)
Other(6)(6)
Other changes in assets and liabilities:
Accounts receivable(112)(119)
Accounts payable(21)(7)
Other354
Net cash flows from operating activities5976
Cash flows used for investing activities:
Construction and acquisition expenditures(376)(253)
Cash receipts on sold receivables192155
Other(6)(9)
Net cash flows used for investing activities(190)(107)
Cash flows from (used for) financing activities:
Common stock dividends(89)(50)
Capital contributions from parent4550
Net change in commercial paper159—
Other(1)(10)
Net cash flows from (used for) financing activities114(10)
Net decrease in cash, cash equivalents and restricted cash(17)(41)
Cash, cash equivalents and restricted cash at beginning of period2953
Cash, cash equivalents and restricted cash at end of period$12$12
Supplemental cash flows information:
Cash paid during the period for:
Interest($58)($32)
Income taxes, net$—($2)
Significant non-cash investing and financing activities:
Accrued capital expenditures$81$110
Beneficial interest obtained in exchange for securitized accounts receivable$86$184

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions)
Revenues:
Electric utility$423$399
Gas utility12297
Other1—
Total revenues546496
Operating expenses:
Electric production fuel and purchased power10896
Electric transmission service5049
Cost of gas sold7253
Other operation and maintenance6763
Depreciation and amortization9390
Taxes other than income taxes1414
Total operating expenses404365
Operating income142131
Other (income) and deductions:
Interest expense4341
Allowance for funds used during construction(9)(9)
Other31
Total other (income) and deductions3733
Income before income taxes10598
Income tax expense (benefit)(5)6
Net income$110$92

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of WPL’s common stock outstanding during the periods presented.

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

March 31, 2025December 31, 2024
(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents$11$51
Accounts receivable, less allowance for expected credit losses235220
Production fuel, at weighted average cost2624
Gas stored underground, at weighted average cost1130
Materials and supplies, at weighted average cost7069
Regulatory assets101133
Prepaid gross receipts tax3951
Other4057
Total current assets533635
Property, plant and equipment, net8,9378,861
Other assets:
Regulatory assets580555
Deferred charges and other5155
Total other assets631610
Total assets$10,101$10,106
LIABILITIES AND EQUITY
Current liabilities:
Commercial paper$212$183
Accounts payable155209
Accrued interest4144
Regulatory liabilities3315
Other8594
Total current liabilities526545
Long-term debt, net3,3713,370
Other liabilities:
Deferred tax liabilities828865
Regulatory liabilities489467
Pension and other benefit obligations92102
Other659656
Total other liabilities2,0682,090
Commitments and contingencies (Note 12)
Equity:
Wisconsin Power and Light Company common equity:
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding6666
Additional paid-in capital2,5332,533
Retained earnings1,5371,502
Total Wisconsin Power and Light Company common equity4,1364,101
Total liabilities and equity$10,101$10,106

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

For the Three Months
Ended March 31,
20252024
(in millions)
Cash flows from operating activities:
Net income$110$92
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization9390
Other(22)(11)
Other changes in assets and liabilities:
Regulatory assets629
Accounts payable(24)15
Regulatory liabilities37(18)
Deferred income taxes(24)(7)
Other1451
Net cash flows from operating activities190241
Cash flows used for investing activities:
Construction and acquisition expenditures(178)(225)
Other(7)12
Net cash flows used for investing activities(185)(213)
Cash flows used for financing activities:
Common stock dividends(75)(49)
Capital contributions from parent—55
Proceeds from issuance of long-term debt—297
Net change in commercial paper29(318)
Other1(9)
Net cash flows used for financing activities(45)(24)
Net increase (decrease) in cash, cash equivalents and restricted cash(40)4
Cash, cash equivalents and restricted cash at beginning of period517
Cash, cash equivalents and restricted cash at end of period$11$11
Supplemental cash flows information:
Cash paid during the period for:
Interest($47)($40)
Significant non-cash investing and financing activities:
Accrued capital expenditures$56$91

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

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ALLIANT ENERGY CORPORATION

INTERSTATE POWER AND LIGHT COMPANY

WISCONSIN POWER AND LIGHT COMPANY

COMBINED NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2024 Form 10-K.

In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the three months ended March 31, 2025 are not necessarily indicative of results that may be expected for the year ending December 31, 2025.

A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.

NOTE 2. REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

Regulatory assets were comprised of the following items (in millions):

Alliant EnergyIPLWPL
March 31, 2025December 31, 2024March 31, 2025December 31, 2024March 31, 2025December 31, 2024
Tax-related$1,011$989$884$870$127$119
Asset retirement obligations414401289281125120
Pension and OPEB costs312315156157156158
Assets retired early1731801621681112
Commodity cost recovery5668225466
Derivatives536011154245
Non-service pension and OPEB costs535120193332
WPL’s Western Wisconsin gas distribution expansion investments4142——4142
Other16116869749294
$2,274$2,274$1,593$1,586$681$688

Derivatives - Refer to Note 10 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three months ended March 31, 2025, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.

Regulatory liabilities were comprised of the following items (in millions):

Alliant EnergyIPLWPL
March 31, 2025December 31, 2024March 31, 2025December 31, 2024March 31, 2025December 31, 2024
Tax-related$595$582$276$286$319$296
Cost of removal obligations341347201205140142
Derivatives615331293024
Commodity cost recovery40172712135
Other462926142015
$1,083$1,028$561$546$522$482
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NOTE 3. RECEIVABLES

Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of March 31, 2025, IPL had no available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three months ended March 31 were as follows (in millions):

20252024
Maximum outstanding aggregate cash proceeds$110$79
Average outstanding aggregate cash proceeds10824

The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

March 31, 2025December 31, 2024
Customer accounts receivable$139$137
Unbilled utility revenues72108
Receivables sold to third party211245
Less: cash proceeds11070
Deferred proceeds101175
Less: allowance for expected credit losses1512
Fair value of deferred proceeds$86$163

As of March 31, 2025, outstanding receivables past due under the Receivables Agreement were $27 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three months ended March 31 were as follows (in millions):

20252024
Collections$607$557
Write-offs, net of recoveries33

NOTE 4. INVESTMENTS

Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):

20252024
ATC Holdings($14)($12)
Other1(3)
($13)($15)

NOTE 5. COMMON EQUITY

Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:

Shares outstanding, January 1, 2025256,690,222
Shareowner Direct Plan99,700
Equity-based compensation plans86,377
Shares outstanding, March 31, 2025256,876,299
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Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant EnergyAccumulatedShares in
AdditionalOtherDeferredTotal
CommonPaid-InRetainedComprehensiveCompensationCommon
StockCapitalEarningsIncome (Loss)TrustEquity
Three Months Ended March 31, 2025
Beginning balance, December 31, 2024$3$3,060$3,954$1($14)$7,004
Net income attributable to Alliant Energy common shareowners213213
Common stock dividends ($0.5075 per share)(130)(130)
Shareowner Direct Plan issuances66
Equity-based compensation plans and other11
Other comprehensive loss, net of tax(1)(1)
Ending balance, March 31, 2025$3$3,066$4,037$—($13)$7,093
Three Months Ended March 31, 2024
Beginning balance, December 31, 2023$3$3,030$3,756$1($13)$6,777
Net income attributable to Alliant Energy common shareowners158158
Common stock dividends ($0.48 per share)(123)(123)
Shareowner Direct Plan issuances66
Equity-based compensation plans and other(3)1(2)
Other comprehensive income, net of tax11
Ending balance, March 31, 2024$3$3,033$3,791$2($12)$6,817
IPLAdditionalTotal
CommonPaid-InRetainedCommon
StockCapitalEarningsEquity
Three Months Ended March 31, 2025
Beginning balance, December 31, 2024$33$3,212$1,216$4,461
Net income110110
Common stock dividends(89)(89)
Capital contributions from parent4545
Ending balance, March 31, 2025$33$3,257$1,237$4,527
Three Months Ended March 31, 2024
Beginning balance, December 31, 2023$33$2,887$1,054$3,974
Net income6363
Common stock dividends(50)(50)
Capital contributions from parent5050
Ending balance, March 31, 2024$33$2,937$1,067$4,037
WPLAdditionalTotal
CommonPaid-InRetainedCommon
StockCapitalEarningsEquity
Three Months Ended March 31, 2025
Beginning balance, December 31, 2024$66$2,533$1,502$4,101
Net income110110
Common stock dividends(75)(75)
Ending balance, March 31, 2025$66$2,533$1,537$4,136
Three Months Ended March 31, 2024
Beginning balance, December 31, 2023$66$2,478$1,353$3,897
Net income9292
Common stock dividends(49)(49)
Capital contributions from parent5555
Ending balance, March 31, 2024$66$2,533$1,396$3,995
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NOTE 6. DEBT

NOTE 6(a) Short-term Debt - In March 2025, Alliant Energy, IPL and WPL reallocated credit facility capacity amounts to $550 million for Alliant Energy at the parent company level, $350 million for IPL and $400 million for WPL, within the $1.3 billion total commitment. Information regarding commercial paper classified as short-term debt was as follows (dollars in millions):

March 31, 2025Alliant EnergyIPLWPL
Amount outstanding$678$109$212
Weighted average interest rates4.6%4.6%4.6%
Available credit facility capacity (a)$522$141$188
Alliant EnergyIPLWPL
Three Months Ended March 31202520242025202420252024
Maximum amount outstanding (based on daily outstanding balances)$678$632$127$14$224$390
Average amount outstanding (based on daily outstanding balances)$541$487$53$1$159$255
Weighted average interest rates4.5%5.5%4.6%5.5%4.5%5.5%

(a)Alliant Energy’s and IPL’s available credit facility capacities reflect outstanding commercial paper classified as both short- and long-term debt at March 31, 2025.

NOTE 6(b) Long-term Debt - In March 2025, AEF entered into a $300 million variable rate (5% as of March 31, 2025) term loan credit agreement (with Alliant Energy as guarantor), which expires in March 2026. This term loan credit agreement amended and restated the term loan credit agreement that expired in March 2025, and retired the $300 million variable rate term loan set forth therein. AEF’s restated term loan credit agreement includes an option to increase the amount outstanding with one or more additional term loans in an aggregate amount not to exceed $100 million.

As of March 31, 2025, $100 million of commercial paper was recorded in “Long-term debt, net” on Alliant Energy’s and IPL’s balance sheets due to the existence of the long-term single credit facility that back-stops this commercial paper balance, along with Alliant Energy’s and IPL’s intent and ability to refinance these balances on a long-term basis. As of March 31, 2025, this commercial paper balance had a 4.6% interest rate. In the second quarter of 2025, Alliant Energy’s and IPL’s commercial paper classified as long-term debt increased $50 million.

Convertible Senior Notes - As of March 31, 2025, the conditions allowing holders of Alliant Energy’s convertible senior notes due 2026 (the Notes) to convert their Notes were not met, and the Notes were classified as “Current maturities of long-term debt” on Alliant Energy’s balance sheet. As of March 31, 2025, the net carrying amount of the Notes was $572 million, with unamortized debt issuance costs of $3 million, and the estimated fair value (Level 2) of the Notes was $617 million. As of March 31, 2025, there were no shares of Alliant Energy’s common stock related to the potential conversion of the Notes included in diluted EPS based on Alliant Energy’s average stock prices and the relevant terms of the Notes.

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NOTE 7. REVENUES

Disaggregation of revenues from contracts with customers is provided for each reportable segment (IPL and WPL), as well as by customer class within electric and gas sales, as follows (in millions):

Alliant EnergyIPLWPL
Three Months Ended March 31202520242025202420252024
Electric Utility:
Retail - residential$323$297$155$150$168$147
Retail - commercial2131861351147872
Retail - industrial237223119112118111
Wholesale484714133434
Bulk power and other3238732535
Total Electric Utility853791430392423399
Gas Utility:
Retail - residential14512673687258
Retail - commercial736132304131
Retail - industrial653332
Transportation/other161310766
Total Gas Utility24020511810812297
Other Utility:
Steam10121012——
Other utility31211—
Total Other Utility131312131—
Non-Utility and Other:
Travero and other2222————
Total Non-Utility and Other2222————
Total revenues$1,128$1,031$560$513$546$496

NOTE 8. INCOME TAXES

Income Tax Rates - Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, investment tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. Alliant Energy’s, IPL’s and WPL’s effective income tax rates were lower in the first quarter of 2025 compared to the same period in 2024 primarily due to the additional tax credits from renewable generation and energy storage projects placed in service in 2024 and/or expected to be placed in service in 2025.

Alliant EnergyIPLWPL
202520242025202420252024
Overall income tax rate(28%)(7%)(57%)(19%)(5%)6%

Deferred Tax Assets and Liabilities -

Carryforwards - At March 31, 2025, the carryforwards and expiration dates were estimated as follows (in millions):

Range of Expiration DatesAlliant EnergyIPLWPL
State net operating losses2025-2045$336$7$1
Federal tax credits2033-2045701473215

NOTE 9. BENEFIT PLANS

NOTE 9(a) Pension and OPEB Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

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Defined Benefit Pension PlansOPEB Plans
Alliant Energy2025202420252024
Service cost$1$1$—$—
Interest cost111122
Expected return on plan assets(13)(13)(1)(1)
Amortization of actuarial loss66——
$5$5$1$1
Defined Benefit Pension PlansOPEB Plans
IPL2025202420252024
Service cost$1$1$—$—
Interest cost5511
Expected return on plan assets(6)(7)(1)(1)
Amortization of actuarial loss22——
$2$1$—$—
Defined Benefit Pension PlansOPEB Plans
WPL2025202420252024
Interest cost$5$5$1$1
Expected return on plan assets(6)(6)——
Amortization of actuarial loss33——
$2$2$1$1

NOTE 9(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):

Alliant EnergyIPLWPL
202520242025202420252024
Compensation expense$4$4$2$2$2$2
Income tax benefits1111——

As of March 31, 2025, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $22 million, $11 million and $10 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.

For the three months ended March 31, 2025, performance shares and restricted stock units were granted to key employees under the equity-based compensation plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.

Weighted Average
GrantsGrant Date Fair Value
Performance shares (total shareowner return metric)78,689$69.33
Performance shares (net income and environmental metrics)89,93061.62
Restricted stock units82,64161.62

As of March 31, 2025, 408,289 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

NOTE 10. DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of March 31, 2025, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and financial transmission rights (FTRs) that were accounted for as commodity derivative instruments were as follows (units in thousands; megawatt-hour (MWh); dekatherm (Dth)):

ElectricityFTRsNatural GasDiesel Fuel
MWhsYearsMWhsYearsDthsYearsGallonsYears
Alliant Energy1,8832025-20264,0802025158,4932025-20321,8902025
IPL5442025-20261,432202567,8742025-2030——
WPL1,3392025-20262,648202590,6192025-20321,8902025
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Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

Alliant EnergyIPLWPL
March 31, 2025December 31, 2024March 31, 2025December 31, 2024March 31, 2025December 31, 2024
Current derivative assets$44$41$26$29$18$12
Non-current derivative assets263414191215
Current derivative liabilities16266111015
Non-current derivative liabilities3632423230

Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets result in comparable changes to regulatory assets/liabilities on the balance sheets.

Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At March 31, 2025 and December 31, 2024, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.

Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, derivative assets and derivative liabilities related to commodity contracts would have been presented on the balance sheets as follows (in millions):

Alliant EnergyIPLWPL
GrossGrossGross
(as reported)Net(as reported)Net(as reported)Net
March 31, 2025
Derivative assets$70$59$40$35$30$24
Derivative liabilities52411054236
December 31, 2024
Derivative assets756448432721
Derivative liabilities58471384539

Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.

NOTE 11. FAIR VALUE MEASUREMENTS

Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant EnergyMarch 31, 2025December 31, 2024
Fair ValueFair Value
CarryingLevelLevelLevelCarryingLevelLevelLevel
Amount123TotalAmount123Total
Assets:
Money market fund investments$—$—$—$—$—$52$52$—$—$52
Commodity derivatives70—59117075—482775
Interest rate derivatives—————1—1—1
Deferred proceeds86——8686163——163163
Liabilities:
Commodity derivatives52—5025258—56258
Long-term debt (incl. current maturities)9,951—9,526—9,5269,848—9,577—9,577
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IPLMarch 31, 2025December 31, 2024
Fair ValueFair Value
CarryingLevelLevelLevelCarryingLevelLevelLevel
Amount123TotalAmount123Total
Assets:
Money market fund investments$—$—$—$—$—$9$9$—$—$9
Commodity derivatives40—29114048—262248
Deferred proceeds86——8686163——163163
Liabilities:
Commodity derivatives10—821013—11213
Long-term debt (incl. current maturities)4,191—3,891—3,8914,090—3,736—3,736
WPLMarch 31, 2025December 31, 2024
Fair ValueFair Value
CarryingLevelLevelLevelCarryingLevelLevelLevel
Amount123TotalAmount123Total
Assets:
Money market fund investments$—$—$—$—$—$43$43$—$—$43
Commodity derivatives30—30—3027—22527
Liabilities:
Commodity derivatives42—42—4245—45—45
Long-term debt3,371—3,221—3,2213,370—3,170—3,170

Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions):

Alliant EnergyCommodity Contract Derivative
Assets and (Liabilities), netDeferred Proceeds
Three Months Ended March 312025202420252024
Beginning balance, January 1$25$24$163$216
Total net losses included in changes in net assets (realized/unrealized)(2)(3)——
Settlements (a)(14)(14)(77)(32)
Ending balance, March 31$9$7$86$184
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31($2)($3)$—$—
IPLCommodity Contract Derivative
Assets and (Liabilities), netDeferred Proceeds
Three Months Ended March 312025202420252024
Beginning balance, January 1$20$19$163$216
Total net losses included in changes in net assets (realized/unrealized)—(4)——
Settlements (a)(11)(10)(77)(32)
Ending balance, March 31$9$5$86$184
The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at March 31$—($4)$—$—
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WPLCommodity Contract Derivative
Assets and (Liabilities), net
Three Months Ended March 3120252024
Beginning balance, January 1$5$5
Total net gains (losses) included in changes in net assets (realized/unrealized)(2)1
Settlements(3)(4)
Ending balance, March 31$—$2
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at March 31($2)$1

(a)Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.

Commodity Contracts - The fair value of FTRs and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions):

Alliant EnergyIPLWPL
Excluding FTRsFTRsExcluding FTRsFTRsExcluding FTRsFTRs
March 31, 2025($1)$10($1)$10$—$—
December 31, 2024—25—20—5

NOTE 12. COMMITMENTS AND CONTINGENCIES

NOTE 12(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, and improvements at the natural gas-fired Neenah Energy Facility and Sheboygan Falls Energy Facility. At March 31, 2025, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were $301 million, $136 million and $163 million, respectively.

NOTE 12(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 March 31, 2025, the related minimum future commitments, excluding amounts for purchased power commitments that do not have minimum thresholds but will require payment when electricity is generated by the provider, were as follows (in millions):

Alliant EnergyIPLWPL
Natural gas$872$500$372
Coal1126250
Other (a)1305933
$1,114$621$455

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2025.

NOTE 12(c) 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 March 31, 2025, the currently known partnership obligations for the abandonment obligations are estimated at $54 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 March 31, 2025 and December 31, 2024.

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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 purchased power agreement (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 $43 million as of March 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 March 31, 2025 and December 31, 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 March 31, 2025, IPL and WPL provided indemnifications associated with $193 million and $121 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 March 31, 2025, IPL’s and WPL’s related guarantees were approximately $6 million and $15 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 March 31, 2025.

NOTE 12(d) Environmental Matters -

Manufactured Gas Plant (MGP) 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 March 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$8-$30$6-$19$2-$11
Current and non-current environmental liabilities$13$8$5

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 Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. 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: Cross-State Air Pollution Rule, Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.

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NOTE 13. SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s reportable segments, which represents the services provided to their customers, and reconciliation to consolidated amounts, was as follows (in millions):

Utility
TotalAlliant
ReportableEnergy
Three Months Ended March 31, 2025IPLWPLSegmentsOtherConsolidated
Electric utility revenues$430$423$853N/A$853
Gas utility revenues118122240N/A240
Other revenues12113$2235
Total revenues5605461,106221,128
Electric production fuel and purchased power expense67108175N/A175
Electric transmission service expense10850158N/A158
Cost of gas sold expense6572137N/A137
Other operation and maintenance expense826714911160
Other segment items:
Depreciation and amortization expense115932083211
Interest expense47439029119
Equity income from unconsolidated investments, net———(13)(13)
Income tax benefit(40)(5)(45)(2)(47)
Other (a)6814115
Net income (loss)110110220(7)213
Total assets11,54010,10121,6411,21022,851
Investments in equity method subsidiaries51722611633
Construction and acquisition expenditures37617855428582
Utility
TotalAlliant
Three Months Ended March 31, 2024 (amounts may not foot due to rounding)ReportableEnergy
IPLWPLSegmentsOtherConsolidated
Electric utility revenues$392$399$791N/A$791
Gas utility revenues10897205N/A205
Other revenues13—13$2235
Total revenues5134961,009221,031
Electric production fuel and purchased power expense6796163N/A163
Electric transmission service expense10349152N/A152
Cost of gas sold expense6053113N/A114
Other operation and maintenance expense866314911160
Other segment items:
Depreciation and amortization expense96901863189
Interest expense42418324107
Equity income from unconsolidated investments, net———(15)(15)
Income tax expense (benefit)(10)6(4)(6)(10)
Other (a)6612213
Net income63921553158
Total assets10,5329,58120,1131,13521,248
Investments in equity method subsidiaries51621573594
Construction and acquisition expenditures25322547832510

(a)Other segment items for each reportable segment include allowance for funds used during construction, taxes other than income taxes, interest income, and other miscellaneous income and deductions.

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NOTE 14. RELATED PARTIES

Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three months ended March 31 were as follows (in millions):

IPLWPL
2025202420252024
Corporate Services billings$47$43$47$40
Sales credited1—2222
Purchases billed9396197

Net intercompany payables to Corporate Services were as follows (in millions):

IPLWPL
March 31, 2025December 31, 2024March 31, 2025December 31, 2024
Net payables to Corporate Services$125$135$74$64

ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three months ended March 31 were as follows (in millions):

20252024
ATC billings to WPL$38$37
WPL billings to ATC63

WPL owed ATC net amounts of $10 million as of March 31, 2025 and $10 million as of December 31, 2024.

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