UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

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

For the quarterly period ended ~~September 30, 2023~~March 31, 2024

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

For the transition period from to

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

ALLIANT ENERGY CORPORATION

(a Wisconsin Corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 1-9894

IRS Employer Identification Number - 39-1380265

INTERSTATE POWER & LIGHT COMPANY

(an Iowa corporation)

Alliant Energy Tower

Cedar Rapids, Iowa 52401

Telephone (319) 786-4411

Commission File Number - 1-4117

IRS Employer Identification Number - 42-0331370

WISCONSIN POWER & LIGHT COMPANY

(a Wisconsin corporation)

4902 N. Biltmore Lane

Madison, Wisconsin 53718

Telephone (608) 458-3311

Commission File Number - 0-337

IRS Employer Identification Number - 39-0714890

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

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

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

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

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

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

Alliant Energy Corporation - Yes ☒ No ☐

Interstate Power and Light Company - Yes ☒ No ☐

Wisconsin Power and Light Company - Yes ☒ No ☐

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

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

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

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

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

Alliant Energy Corporation ☐

Interstate Power and Light Company ☐

Wisconsin Power and Light Company ☐

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

Alliant Energy Corporation - Yes ☐ No ☒

Interstate Power and Light Company - Yes ☐ No ☒

Wisconsin Power and Light Company - Yes ☐ No ☒

Number of shares outstanding of each class of common stock as of ~~September 30, 2023:~~March 31, 2024:

Alliant Energy Corporation, Common Stock, $0.01 par value, ~~255,179,087~~256,379,032 shares outstanding

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

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

Table of Contents

TABLE OF CONTENTS


			Page
Definitions			1
Forward-looking Statements			1
Part I. Financial Information			3
Item 1. Condensed Consolidated Financial Statements (Unaudited)			3
Alliant Energy Corporation			3
Interstate Power and Light Company			6
Wisconsin Power and Light Company			9
Combined Notes to Condensed Consolidated Financial Statements			12
1. Summary of Significant Accounting Policies			12
2. Regulatory Matters			12
3. Property, Plant and Equipment			13
4 . Receivables			13
5 . Investments			1413
6 . Common Equity			1413
7 . Debt			1615
8 . Revenues			1815
9 . Income Taxes			1816
10 . Benefit Plans			1916

1 1 . Derivative Instruments			2017
1 2 . Fair Value Measurements			2118
1 3 . Commitments and Contingencies			2420
1 4 . Segments of Business			2522
1 5 . Related Parties			2722
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations			2723
Item 3. Quantitative and Qualitative Disclosures About Market Risk			3729
Item 4. Controls and Procedures			3729
Part II. Other Information			3729
Item 1. Legal Proceedings			3729
Item 1A. Risk Factors			3729
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds			3729
Item 5. Other Information			3730
Item 6. Exhibits			3830
Signatures			3830

Table of Contents

DEFINITIONS

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


Abbreviation or Acronym	Definition	Abbreviation or Acronym	Definition
~~2022~~2023 Form 10-K	Combined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, ~~2022~~2023	IUB	Iowa Utilities Board
AEF	Alliant Energy Finance, LLC	MDA	Management’s Discussion and Analysis of Financial Condition and Results of Operations
AFUDC	Allowance for funds used during construction	MISO	Midcontinent Independent System Operator, Inc.
Alliant Energy	Alliant Energy Corporation	MW	Megawatt
ATC	American Transmission Company LLC	MWh	Megawatt-hour
ATC Holdings	Interest in American Transmission Company LLC and ATC Holdco LLC	N/A	Not applicable
Corporate Services	Alliant Energy Corporate Services, Inc.	Note(s)	Combined Notes to Condensed Consolidated Financial Statements
Dth	Dekatherm	OPEB	Other postretirement benefits
EGU	Electric generating unit	PPA	Purchased power agreement
EPA	U.S. Environmental Protection Agency	PSCW	Public Service Commission of Wisconsin
EPS	Earnings per weighted average common share	SEC	Securities and Exchange Commission
Financial Statements	Condensed Consolidated Financial Statements	U.S.	United States of America
FTR	Financial transmission right	West Riverside	West Riverside Energy Center and Solar Facility
GAAP	U.S. generally accepted accounting principles	Whiting Petroleum	Whiting Petroleum Corporation
IPL	Interstate Power and Light Company	WPL	Wisconsin Power and Light Company

FORWARD-LOOKING STATEMENTS

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

•the direct or indirect effects resulting from cybersecurity incidents or attacks on Alliant Energy, IPL, WPL, or their suppliers, contractors and partners, or responses to such incidents;

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

•economic conditions and the impact of business or facility closures in IPL’s and WPL’s service territories;

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

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

•~~inflation and higher interest rates;~~

•changes in the price of delivered natural gas, transmission, purchased electricity and delivered coal, particularly during elevated market prices, and any resulting changes to counterparty credit risk, due to shifts in supply and demand caused by market conditions, regulations and MISO’s seasonal resource adequacy process;

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

•weather effects on utility sales volumes and operations;

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

•the ability to obtain regulatory approval for construction projects with acceptable conditions;

•the ability to complete construction of renewable generation and storage projects by planned in-service dates and within the cost targets set by regulators due to cost increases of and access to materials, equipment and commodities, which could result from tariffs, duties or other assessments, such as any additional tariffs resulting from U.S. Department of Commerce investigations into and any decisions made regarding the sourcing of solar project materials and equipment from certain countries, labor issues or supply shortages, the ability to successfully resolve warranty issues or contract disputes, the ability to achieve the expected level of tax benefits based on tax guidelines, project costs and the level of electricity output generated by qualifying generating facilities, and the ability to efficiently utilize the renewable generation and storage project tax benefits for the benefit of customers;

•WPL’s ability to obtain rate relief to allow for the return on costs of solar generation projects that exceed initial cost estimates;

•the impacts of changes in the tax code, including tax rates, minimum tax rates, adjustments made to deferred tax assets and liabilities, and changes impacting the availability of and ability to transfer renewable tax credits;

•the ability to utilize tax credits generated to date, and those that may be generated in the future, before they expire, as well as the ability to transfer tax credits that may be generated in the future at adequate pricing;

•disruptions to ongoing operations and the supply of materials, services, equipment and commodities needed to construct solar generation, battery storage and electric and gas distribution projects, which may result from geopolitical issues, supplier manufacturing constraints, regulatory requirements, labor issues or transportation issues, and thus affect the ability to meet capacity requirements and result in increased capacity expense;

•inflation and higher interest rates;


			1

Table of Contents

•the future development of technologies related to electrification, and the ability to reliably store and manage electricity;

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

•~~the impacts of~~orders and changes in ~~the tax code, including tax rates, minimum tax rates, adjustments made to deferred tax assets and liabilities, and changes impacting the availability of renewable tax credits;~~public policy;


			1

~~Table~~ of ~~Contents~~

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

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

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

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

•impacts that terrorist attacks may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities, or on the operations of Alliant Energy’s investments;

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

•~~weather effects on results of utility operations;~~

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

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

•issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits and future changes in environmental laws and regulations, including ~~changes to~~ the Coal Combustion Residuals Rule, Cross-State Air Pollution Rule and federal, state or local regulations for greenhouse gases emissions reductions from new and existing fossil-fueled EGUs under the Clean Air Act, and litigation associated with environmental requirements;

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

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

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

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

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

•~~the direct or indirect effects resulting from the ongoing novel coronavirus (COVID-19) pandemic and the spread of variant strains;~~

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

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

•material changes in employee-related benefit and compensation costs, including settlement losses related to pension plans;

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

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

•impacts on equity income from unconsolidated investments from changes in valuations of the assets held, as well as potential changes to ATC’s authorized return on equity;

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

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

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

•the direct or indirect effects resulting from pandemics;

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

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

•other factors listed in MDA and Risk Factors in Item 1A in the ~~2022~~2023 Form 10-K.

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

Available Information. Alliant Energy routinely posts important information on its website and considers the Investors section of its website, www.alliantenergy.com/investors, a channel of distribution for material information. Information contained on Alliant Energy’s website is not incorporated ~~herein.~~herein by reference.


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Table of Contents

PART I. FINANCIAL INFORMATION

ITEM 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)


		For the Three Months
		For the Three Months
		For the Three Months
		Ended March 31,
		Ended March 31,
		Ended March 31,
		2024
		2024
		2024
		(in millions, except per share amounts)
		(in millions, except per share amounts)
		(in millions, except per share amounts)
Revenues:
Electric utility
Electric utility
Electric utility
Gas utility
Gas utility
Gas utility
Other utility
Other utility
Other utility
Non-utility
Non-utility
Non-utility
Total revenues
Total revenues
Total revenues
Operating expenses:
Operating expenses:
Operating expenses:
Electric production fuel and purchased power
Electric production fuel and purchased power
Electric production fuel and purchased power
Electric transmission service
Electric transmission service
Electric transmission service
Cost of gas sold
Cost of gas sold
Cost of gas sold
Other operation and maintenance
Other operation and maintenance
Other operation and maintenance
Depreciation and amortization
Depreciation and amortization
Depreciation and amortization
Taxes other than income taxes
Taxes other than income taxes
Taxes other than income taxes
Total operating expenses
Total operating expenses
Total operating expenses
Operating income
Operating income
Operating income
Other (income) and deductions:
Other (income) and deductions:
Other (income) and deductions:
Interest expense
Interest expense
Interest expense
Equity income from unconsolidated investments, net
Equity income from unconsolidated investments, net
Equity income from unconsolidated investments, net
Allowance for funds used during construction
Allowance for funds used during construction
Allowance for funds used during construction
Other
Other
Other
Total other (income) and deductions
Total other (income) and deductions
Total other (income) and deductions
Income before income taxes
Income before income taxes
Income before income taxes
Income tax benefit
Income tax benefit
Income tax benefit

		For the Three Months		For the Nine Months
		Ended September 30,		Ended September 30,
		2023	2022	2023	2022
Net income attributable to Alliant Energy common shareowners
		(in millions, except per share amounts)
Revenues:
Electric utility		$995	$1,039	$2,562	$2,624
Gas utility		47	62	400	418
Other utility		13	11	38	35
Non-utility		22	23	66	70
Total revenues		1,077	1,135	3,066	3,147
Operating expenses:
Electric production fuel and purchased power		231	274	553	633
Electric transmission service		154	157	438	428
Cost of gas sold		12	26	226	242
Other operation and maintenance		160	172	499	492
Depreciation and amortization		170	169	503	501
Taxes other than income taxes		28	28	87	82
Total operating expenses		755	826	2,306	2,378
Operating income		322	309	760	769
Other (income) and deductions:
Interest expense		99	83	289	235
Equity income from unconsolidated investments, net		(14)	(5)	(45)	(37)
Allowance for funds used during construction		(28)	(10)	(71)	(34)
Other		1	—	2	—
Total other (income) and deductions		58	68	175	164
Income before income taxes		264	241	585	605
Income tax expense		5	14	3	26

Net income attributable to Alliant Energy common shareowners

Net income attributable to Alliant Energy common shareowners	Net income attributable to Alliant Energy common shareowners	$259	$227	$582	$579
Weighted average number of common shares outstanding:	Weighted average number of common shares outstanding:
Weighted average number of common shares outstanding:
Weighted average number of common shares outstanding:
Basic
Basic
Basic	Basic	253.5	251.0	252.1	250.8
Diluted	Diluted	253.8	251.3	252.4	251.1
Diluted
Diluted

Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)

Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)

Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)	Earnings per weighted average common share attributable to Alliant Energy common shareowners (basic and diluted)	$1.02	$0.90	$2.31	$2.31

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


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ALLIANT ENERGY CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)


		September 30, 2023	December 31, 2022
		(in millions, except per share and share amounts)
	March 31, 2024					March 31, 2024				December 31, 2023
	(in millions, except per share and share amounts)								(in millions, except per share and share amounts)
ASSETS	ASSETS
Current assets:	Current assets:
Current assets:
Current assets:
Cash and cash equivalents
Cash and cash equivalents
Cash and cash equivalents	Cash and cash equivalents	$206	$20	$32			$62
Accounts receivable, less allowance for expected credit losses	Accounts receivable, less allowance for expected credit losses	486	516	Accounts receivable, less allowance for expected credit losses	426			475

Production fuel, at weighted average cost
Production fuel, at weighted average cost
Production fuel, at weighted average cost	Production fuel, at weighted average cost	44	53	60			62
Gas stored underground, at weighted average cost	Gas stored underground, at weighted average cost	87	132	Gas stored underground, at weighted average cost	52			79
Materials and supplies, at weighted average cost	Materials and supplies, at weighted average cost	196	140	Materials and supplies, at weighted average cost	208			202
Regulatory assets	Regulatory assets	179	166	Regulatory assets	218			232

Other	Other	174	223
Other
Other					112			160
Total current assets	Total current assets	1,372	1,250	Total current assets	1,108			1,272
Property, plant and equipment, net	Property, plant and equipment, net	16,633	16,247	Property, plant and equipment, net	17,354			17,157
Investments:	Investments:
ATC Holdings
ATC Holdings
ATC Holdings	ATC Holdings	380	358	392			386
Other	Other	214	201	Other	219			216
Total investments	Total investments	594	559	Total investments	611			602
Other assets:	Other assets:
Regulatory assets	Regulatory assets	2,090	1,880
Regulatory assets
Regulatory assets					2,002			2,029
Deferred charges and other	Deferred charges and other	215	227	Deferred charges and other	173			177
Total other assets	Total other assets	2,305	2,107	Total other assets	2,175			2,206
Total assets	Total assets	$20,904	$20,163	Total assets	$21,248			$21,237


LIABILITIES AND EQUITY	LIABILITIES AND EQUITY
Current liabilities:	Current liabilities:
Current liabilities:
Current liabilities:
Current maturities of long-term debt
Current maturities of long-term debt
Current maturities of long-term debt	Current maturities of long-term debt	$409	$408	$809		$809
Commercial paper	Commercial paper	451	642	Commercial paper	334		475
Other short-term borrowings		50	—

Accounts payable
Accounts payable
Accounts payable	Accounts payable	604	756	438		611

Regulatory liabilities
Regulatory liabilities
Regulatory liabilities	Regulatory liabilities	92	206	100		107
Other	Other	329	351	Other	303		302
Total current liabilities	Total current liabilities	1,935	2,363	Total current liabilities	1,984		2,304
Long-term debt, net (excluding current portion)	Long-term debt, net (excluding current portion)	8,429	7,668	Long-term debt, net (excluding current portion)	8,524		8,225
Other liabilities:	Other liabilities:
Deferred tax liabilities
Deferred tax liabilities
Deferred tax liabilities	Deferred tax liabilities	1,913	1,943	2,038		2,042
Regulatory liabilities	Regulatory liabilities	1,095	1,118	Regulatory liabilities	1,036		1,023
Pension and other benefit obligations	Pension and other benefit obligations	262	277	Pension and other benefit obligations	245		249
Other	Other	544	518	Other	604		617
Total other liabilities	Total other liabilities	3,814	3,856	Total other liabilities	3,923		3,931
Commitments and contingencies (Note 1 3)	Commitments and contingencies (Note 1 3)			Commitments and contingencies (Note 1 3)
Equity:	Equity:
Alliant Energy Corporation common equity:	Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 255,179,087 and 251,134,966 shares outstanding		3	3
Alliant Energy Corporation common equity:
Alliant Energy Corporation common equity:
Common stock - $0.01 par value - 480,000,000 shares authorized; 256,379,032 and 256,096,848 shares outstanding
Common stock - $0.01 par value - 480,000,000 shares authorized; 256,379,032 and 256,096,848 shares outstanding
Common stock - $0.01 par value - 480,000,000 shares authorized; 256,379,032 and 256,096,848 shares outstanding					3		3
Additional paid-in capital	Additional paid-in capital	2,982	2,777	Additional paid-in capital	3,033		3,030
Retained earnings	Retained earnings	3,750	3,509	Retained earnings	3,791		3,756
Accumulated other comprehensive income	Accumulated other comprehensive income	4	—	Accumulated other comprehensive income	2		1
Shares in deferred compensation trust - 393,781 and 402,134 shares at a weighted average cost of $34.13 and $32.63 per share		(13)	(13)
Shares in deferred compensation trust - 341,937 and 379,006 shares at a weighted average cost of $34.96 and $34.48 per share				Shares in deferred compensation trust - 341,937 and 379,006 shares at a weighted average cost of $34.96 and $34.48 per share	(12)		(13)
Total Alliant Energy Corporation common equity	Total Alliant Energy Corporation common equity	6,726	6,276	Total Alliant Energy Corporation common equity	6,817		6,777

Total liabilities and equity	Total liabilities and equity	$20,904	$20,163

Total liabilities and equity

Total liabilities and equity					$21,248		$21,237

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								For the Three Months
	Ended March 31,								Ended March 31,
	2024					2024				2023
	(in millions)								(in millions)
Cash flows from operating activities:
Net income
Net income
Net income					$158			$163
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization
Depreciation and amortization
Depreciation and amortization					189			166

		For the Nine Months
		Ended September 30,
Other
		2023	2022
		(in millions)
Cash flows from operating activities:
Net income		$582	$579
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization		503	501
Other

Equity component of allowance for funds used during construction		(53)	(25)

Other	Other	15	25	(18)			(6)
Other changes in assets and liabilities:	Other changes in assets and liabilities:
Accounts receivable	Accounts receivable	(279)	(425)
Materials and supplies		(56)	(13)
Accounts receivable
Accounts receivable					(116)			(86)

Gas stored underground
Gas stored underground
Gas stored underground					27			68
Derivative assets	Derivative assets	102	(184)	Derivative assets	30			115
Regulatory assets	Regulatory assets	40	(102)	Regulatory assets	35			(32)
Accounts payable	Accounts payable	(91)	90	Accounts payable	12			(97)
Derivative liabilities		(13)	89

Regulatory liabilities
Regulatory liabilities
Regulatory liabilities	Regulatory liabilities	(126)	89	(14)			(95)

Other

Other

Other	Other	(2)	(139)	4			(8)
Net cash flows from operating activities	Net cash flows from operating activities	622	485	Net cash flows from operating activities	307			188
Cash flows used for investing activities:	Cash flows used for investing activities:
Construction and acquisition expenditures:	Construction and acquisition expenditures:
Construction and acquisition expenditures:
Construction and acquisition expenditures:
Utility business
Utility business
Utility business	Utility business	(1,201)	(873)	(478)			(417)
Other	Other	(92)	(69)	Other	(32)			(34)
Cash receipts on sold receivables	Cash receipts on sold receivables	306	358	Cash receipts on sold receivables	155			173
Proceeds from sales of partial ownership interest in West Riverside		120	—
Proceeds from sale of partial ownership interest in West Riverside				Proceeds from sale of partial ownership interest in West Riverside	—			25
Other	Other	(85)	(15)	Other	2			(10)
Net cash flows used for investing activities	Net cash flows used for investing activities	(952)	(599)	Net cash flows used for investing activities	(353)			(263)
Cash flows from financing activities:	Cash flows from financing activities:
Common stock dividends	Common stock dividends	(341)	(322)
Proceeds from issuance of common stock, net		201	19
Common stock dividends
Common stock dividends					(123)			(113)

Proceeds from issuance of long-term debt
Proceeds from issuance of long-term debt
Proceeds from issuance of long-term debt	Proceeds from issuance of long-term debt	1,158	1,238	597			862
Payments to retire long-term debt	Payments to retire long-term debt	(404)	(379)	Payments to retire long-term debt	(300)			—
Net change in commercial paper and other short-term borrowings	Net change in commercial paper and other short-term borrowings	(141)	(132)	Net change in commercial paper and other short-term borrowings	(141)			(532)
Contributions from noncontrolling interest		—	29
Distributions to noncontrolling interest		—	(29)

Other

Other

Other	Other	42	(3)	(15)			(5)
Net cash flows from financing activities	Net cash flows from financing activities	515	421	Net cash flows from financing activities	18			212
Net increase in cash, cash equivalents and restricted cash		185	307
Net increase (decrease) in cash, cash equivalents and restricted cash				Net increase (decrease) in cash, cash equivalents and restricted cash	(28)			137
Cash, cash equivalents and restricted cash at beginning of period	Cash, cash equivalents and restricted cash at beginning of period	24	40	Cash, cash equivalents and restricted cash at beginning of period	63			24
Cash, cash equivalents and restricted cash at end of period	Cash, cash equivalents and restricted cash at end of period	$209	$347	Cash, cash equivalents and restricted cash at end of period	$35			$161
Supplemental cash flows information:	Supplemental cash flows information:
Cash paid during the period for:	Cash paid during the period for:
Cash paid during the period for:
Cash paid during the period for:
Interest
Interest
Interest	Interest	($280)	($220)	($97)			($93)
Income taxes, net	Income taxes, net	($6)	($7)	Income taxes, net	($2)			$—
Significant non-cash investing and financing activities:	Significant non-cash investing and financing activities:
Accrued capital expenditures	Accrued capital expenditures	$287	$403
Accrued capital expenditures
Accrued capital expenditures					$204			$254
Beneficial interest obtained in exchange for securitized accounts receivable	Beneficial interest obtained in exchange for securitized accounts receivable	$236	$248	Beneficial interest obtained in exchange for securitized accounts receivable	$184			$153

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


			5

Table of Contents

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)


		For the Three Months		For the Nine Months
		Ended September 30,		Ended September 30,
		2023	2022	2023	2022
		(in millions)
		For the Three Months
		For the Three Months
		For the Three Months
		Ended March 31,
		Ended March 31,
		Ended March 31,
		2024
		2024
		2024
		(in millions)
		(in millions)
		(in millions)
Revenues:	Revenues:
Electric utility	Electric utility	$551	$596	$1,370	$1,438
Electric utility
Electric utility
Gas utility
Gas utility
Gas utility	Gas utility	31	33	224	224
Steam and other	Steam and other	12	11	36	34
Steam and other
Steam and other
Total revenues
Total revenues
Total revenues	Total revenues	594	640	1,630	1,696
Operating expenses:	Operating expenses:
Operating expenses:
Operating expenses:
Electric production fuel and purchased power
Electric production fuel and purchased power
Electric production fuel and purchased power	Electric production fuel and purchased power	99	140	213	290
Electric transmission service	Electric transmission service	115	115	316	303
Electric transmission service
Electric transmission service
Cost of gas sold
Cost of gas sold
Cost of gas sold	Cost of gas sold	12	14	127	126
Other operation and maintenance	Other operation and maintenance	84	90	264	260
Other operation and maintenance
Other operation and maintenance
Depreciation and amortization
Depreciation and amortization
Depreciation and amortization	Depreciation and amortization	97	95	288	285
Taxes other than income taxes	Taxes other than income taxes	14	15	43	43
Taxes other than income taxes
Taxes other than income taxes
Total operating expenses
Total operating expenses
Total operating expenses	Total operating expenses	421	469	1,251	1,307
Operating income	Operating income	173	171	379	389
Operating income
Operating income
Other (income) and deductions:
Other (income) and deductions:
Other (income) and deductions:	Other (income) and deductions:
Interest expense	Interest expense	38	37	113	111
Interest expense
Interest expense
Allowance for funds used during construction
Allowance for funds used during construction
Allowance for funds used during construction	Allowance for funds used during construction	(6)	(3)	(13)	(8)
Other	Other	2	(1)	3	(2)
Other
Other
Total other (income) and deductions
Total other (income) and deductions
Total other (income) and deductions	Total other (income) and deductions	34	33	103	101
Income before income taxes	Income before income taxes	139	138	276	288
Income before income taxes
Income before income taxes
Income tax benefit
Income tax benefit
Income tax benefit	Income tax benefit	(31)	(16)	(55)	(39)

Net income	Net income	$170	$154	$331	$327

Net income

Net income

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.


			6

Table of Contents

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)


		September 30, 2023	December 31, 2022
		(in millions, except per share and share amounts)
	March 31, 2024					March 31, 2024				December 31, 2023
	(in millions, except per share and share amounts)								(in millions, except per share and share amounts)
ASSETS	ASSETS
Current assets:	Current assets:
Current assets:
Current assets:
Cash and cash equivalents
Cash and cash equivalents
Cash and cash equivalents	Cash and cash equivalents	$188	$15	$12			$53
Accounts receivable, less allowance for expected credit losses	Accounts receivable, less allowance for expected credit losses	258	259	Accounts receivable, less allowance for expected credit losses	204			242

Production fuel, at weighted average cost
Production fuel, at weighted average cost
Production fuel, at weighted average cost	Production fuel, at weighted average cost	22	23	29			27
Gas stored underground, at weighted average cost	Gas stored underground, at weighted average cost	40	60	Gas stored underground, at weighted average cost	17			35
Materials and supplies, at weighted average cost	Materials and supplies, at weighted average cost	111	83	Materials and supplies, at weighted average cost	126			122
Regulatory assets	Regulatory assets	86	85	Regulatory assets	85			93
Other	Other	70	93	Other	42			51
Total current assets	Total current assets	775	618	Total current assets	515			623
Property, plant and equipment, net	Property, plant and equipment, net	8,042	8,046	Property, plant and equipment, net	8,450			8,298
Other assets:	Other assets:
Regulatory assets	Regulatory assets	1,504	1,301
Regulatory assets
Regulatory assets					1,482			1,484
Deferred charges and other	Deferred charges and other	106	110	Deferred charges and other	85			84
Total other assets	Total other assets	1,610	1,411	Total other assets	1,567			1,568
Total assets	Total assets	$10,427	$10,075	Total assets	$10,532			$10,489


LIABILITIES AND EQUITY	LIABILITIES AND EQUITY
Current liabilities:	Current liabilities:

Current liabilities:
Current liabilities:
Current maturities of long-term debt
Current maturities of long-term debt
Current maturities of long-term debt					$500		$500

Accounts payable	Accounts payable	$255	$239
Accounts payable to associated companies		59	28
Accounts payable
Accounts payable					213		262

Accrued taxes
Accrued taxes
Accrued taxes	Accrued taxes	68	52	61		50
Accrued interest	Accrued interest	41	35	Accrued interest	49		40
Regulatory liabilities	Regulatory liabilities	63	114	Regulatory liabilities	79		72
Other	Other	84	113	Other	97		101
Total current liabilities	Total current liabilities	570	581	Total current liabilities	999		1,025
Long-term debt, net		3,944	3,646
Long-term debt, net (excluding current portion)				Long-term debt, net (excluding current portion)	3,445		3,445
Other liabilities:	Other liabilities:
Deferred tax liabilities
Deferred tax liabilities
Deferred tax liabilities	Deferred tax liabilities	987	1,047	1,098		1,091
Regulatory liabilities	Regulatory liabilities	592	640	Regulatory liabilities	569		572
Pension and other benefit obligations	Pension and other benefit obligations	59	62	Pension and other benefit obligations	49		51
Other	Other	286	291	Other	335		331
Total other liabilities	Total other liabilities	1,924	2,040	Total other liabilities	2,051		2,045
Commitments and contingencies (Note 1 3)	Commitments and contingencies (Note 1 3)			Commitments and contingencies (Note 1 3)
Equity:	Equity:
Interstate Power and Light Company common equity:	Interstate Power and Light Company common equity:
Interstate Power and Light Company common equity:
Interstate Power and Light Company common equity:
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding	Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding	33	33	33		33
Additional paid-in capital	Additional paid-in capital	2,867	2,807	Additional paid-in capital	2,937		2,887
Retained earnings	Retained earnings	1,089	968	Retained earnings	1,067		1,054
Total Interstate Power and Light Company common equity	Total Interstate Power and Light Company common equity	3,989	3,808	Total Interstate Power and Light Company common equity	4,037		3,974

Total liabilities and equity	Total liabilities and equity	$10,427	$10,075

Total liabilities and equity

Total liabilities and equity					$10,532		$10,489

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


			7

Table of Contents

INTERSTATE POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)


	For the Three Months								For the Three Months
	Ended March 31,								Ended March 31,
	2024					2024				2023
	(in millions)								(in millions)
Cash flows from operating activities:
Net income
Net income
Net income					$63			$72
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization
Depreciation and amortization
Depreciation and amortization					96			96

Other

Other

Other					(11)			1
Other changes in assets and liabilities:
Accounts receivable
Accounts receivable
Accounts receivable					(119)			(106)

Gas stored underground

Gas stored underground

Gas stored underground					18			34
Derivative assets				Derivative assets	20			69

Accounts payable
Accounts payable
Accounts payable					(7)			(56)

Regulatory liabilities
Regulatory liabilities
Regulatory liabilities					4			(59)

		For the Nine Months
		Ended September 30,
Other
		2023	2022
		(in millions)
Cash flows from operating activities:
Net income		$331	$327
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization		288	285
Other

Deferred tax benefit and tax credits		(17)	(24)
Other		(6)	(8)
Other changes in assets and liabilities:
Accounts receivable		(306)	(397)

Derivative assets		53	(118)
Regulatory assets		55	18
Accounts payable		(45)	71
Derivative liabilities		(25)	62
Regulatory liabilities		(90)	61

Deferred income taxes		(44)	(30)

Other	Other	(3)	(81)	12			(27)
Net cash flows from operating activities	Net cash flows from operating activities	191	166	Net cash flows from operating activities	76			24
Cash flows from (used for) investing activities:	Cash flows from (used for) investing activities:
Construction and acquisition expenditures	Construction and acquisition expenditures	(427)	(269)
Construction and acquisition expenditures
Construction and acquisition expenditures					(253)			(101)
Cash receipts on sold receivables	Cash receipts on sold receivables	306	358	Cash receipts on sold receivables	155			173
Other	Other	(56)	(5)	Other	(9)			(2)
Net cash flows from (used for) investing activities	Net cash flows from (used for) investing activities	(177)	84	Net cash flows from (used for) investing activities	(107)			70
Cash flows from (used for) financing activities:
Cash flows used for financing activities:
Common stock dividends
Common stock dividends
Common stock dividends	Common stock dividends	(210)	(240)	(50)			(70)
Capital contributions from parent	Capital contributions from parent	60	—	Capital contributions from parent	50			—
Proceeds from issuance of long-term debt		296	—

Other	Other	13	1
Net cash flows from (used for) financing activities		159	(239)
Net increase in cash, cash equivalents and restricted cash		173	11

Other

Other					(10)			(4)
Net cash flows used for financing activities				Net cash flows used for financing activities	(10)			(74)
Net increase (decrease) in cash, cash equivalents and restricted cash				Net increase (decrease) in cash, cash equivalents and restricted cash	(41)			20
Cash, cash equivalents and restricted cash at beginning of period	Cash, cash equivalents and restricted cash at beginning of period	15	34	Cash, cash equivalents and restricted cash at beginning of period	53			15
Cash, cash equivalents and restricted cash at end of period	Cash, cash equivalents and restricted cash at end of period	$188	$45	Cash, cash equivalents and restricted cash at end of period	$12			$35
Supplemental cash flows information:	Supplemental cash flows information:
Cash (paid) refunded during the period for:
Cash paid during the period for:
Cash paid during the period for:
Cash paid during the period for:
Interest
Interest
Interest	Interest	($107)	($111)	($32)			($37)
Income taxes, net	Income taxes, net	$36	$33	Income taxes, net	($2)			$—
Significant non-cash investing and financing activities:	Significant non-cash investing and financing activities:
Accrued capital expenditures	Accrued capital expenditures	$108	$43
Accrued capital expenditures
Accrued capital expenditures					$110			$98
Beneficial interest obtained in exchange for securitized accounts receivable	Beneficial interest obtained in exchange for securitized accounts receivable	$236	$248	Beneficial interest obtained in exchange for securitized accounts receivable	$184			$153

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


			8

Table of Contents

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)


		For the Three Months		For the Nine Months
		Ended September 30,		Ended September 30,
		2023	2022	2023	2022
		(in millions)
		For the Three Months
		For the Three Months
		For the Three Months
		Ended March 31,
		Ended March 31,
		Ended March 31,
		2024
		2024
		2024
		(in millions)
		(in millions)
		(in millions)
Revenues:	Revenues:
Electric utility	Electric utility	$444	$443	$1,192	$1,186
Electric utility
Electric utility
Gas utility	Gas utility	16	29	176	194
Other		1	—	2	1
Gas utility
Gas utility

Total revenues

Total revenues

Total revenues	Total revenues	461	472	1,370	1,381
Operating expenses:	Operating expenses:
Operating expenses:
Operating expenses:
Electric production fuel and purchased power
Electric production fuel and purchased power
Electric production fuel and purchased power	Electric production fuel and purchased power	132	134	341	343
Electric transmission service	Electric transmission service	39	42	122	125
Electric transmission service
Electric transmission service
Cost of gas sold
Cost of gas sold
Cost of gas sold	Cost of gas sold	—	13	99	117
Other operation and maintenance	Other operation and maintenance	64	70	197	193
Other operation and maintenance
Other operation and maintenance
Depreciation and amortization
Depreciation and amortization
Depreciation and amortization	Depreciation and amortization	71	71	208	211
Taxes other than income taxes	Taxes other than income taxes	13	11	40	35
Taxes other than income taxes
Taxes other than income taxes
Total operating expenses
Total operating expenses
Total operating expenses	Total operating expenses	319	341	1,007	1,024
Operating income	Operating income	142	131	363	357
Operating income
Operating income
Other (income) and deductions:	Other (income) and deductions:
Other (income) and deductions:
Other (income) and deductions:
Interest expense
Interest expense
Interest expense	Interest expense	38	31	110	86

Allowance for funds used during construction	Allowance for funds used during construction	(22)	(7)	(58)	(26)

Allowance for funds used during construction

Allowance for funds used during construction
Other
Other
Other	Other	(2)	—	(3)	—
Total other (income) and deductions	Total other (income) and deductions	14	24	49	60
Total other (income) and deductions
Total other (income) and deductions
Income before income taxes
Income before income taxes
Income before income taxes	Income before income taxes	128	107	314	297
Income tax expense	Income tax expense	21	16	47	50
Income tax expense
Income tax expense
Net income
Net income
Net income	Net income	$107	$91	$267	$247

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.


			9

Table of Contents

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

September 30,
2023 December 31,
2022
(in millions, except per
share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents $16 $5
Accounts receivable, less allowance for expected credit losses 214 244
Production fuel, at weighted average cost 21 29
Gas stored underground, at weighted average cost 47 73
Materials and supplies, at weighted average cost 82 54
Regulatory assets 93 81
Prepaid gross receipts tax 36 42
Other 50 60
Total current assets 559 588
Property, plant and equipment, net 8,085 7,722
Other assets:
Regulatory assets 586 579
Deferred charges and other 71 98
Total other assets 657 677
Total assets $9,301 $8,987
LIABILITIES AND EQUITY
Current liabilities:
Commercial paper $120 $290
Accounts payable 281 456
Regulatory liabilities 29 92
Other 117 111
Total current liabilities 547 949
Long-term debt, net 3,069 2,770
Other liabilities:
Deferred tax liabilities 796 789
Regulatory liabilities 503 478
Pension and other benefit obligations 128 140
Other 393 370
Total other liabilities 1,820 1,777
Commitments and contingencies (Note 1 3)
Equity:
Wisconsin Power and Light Company common equity:
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding 66 66
Additional paid-in capital 2,478 2,233
Retained earnings 1,321 1,192
Total Wisconsin Power and Light Company common equity 3,865 3,491
Total liabilities and equity $9,301 $8,987


	March 31, 2024	December 31, 2023
	(in millions, except per share and share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$11	$7
Accounts receivable, less allowance for expected credit losses	209	219
Production fuel, at weighted average cost	31	35
Gas stored underground, at weighted average cost	35	44
Materials and supplies, at weighted average cost	78	77
Regulatory assets	133	139
Prepaid gross receipts tax	38	49
Other	19	43
Total current assets	554	613
Property, plant and equipment, net	8,450	8,415
Other assets:
Regulatory assets	520	545
Deferred charges and other	57	61
Total other assets	577	606
Total assets	$9,581	$9,634


LIABILITIES AND EQUITY
Current liabilities:

Commercial paper	$—	$318

Accounts payable	174	293

Accrued interest	42	40
Regulatory liabilities	21	35
Other	105	89
Total current liabilities	342	775
Long-term debt, net	3,367	3,070
Other liabilities:
Deferred tax liabilities	811	827
Regulatory liabilities	467	451

Pension and other benefit obligations	119	121
Other	480	493
Total other liabilities	1,877	1,892
Commitments and contingencies (Note 1 3)
Equity:
Wisconsin Power and Light Company common equity:
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding	66	66
Additional paid-in capital	2,533	2,478
Retained earnings	1,396	1,353
Total Wisconsin Power and Light Company common equity	3,995	3,897


Total liabilities and equity	$9,581	$9,634

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


			10

Table of Contents

WISCONSIN POWER AND LIGHT COMPANY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)


		For the Nine Months
		Ended September 30,
		2023	2022
		(in millions)
	For the Three Months								For the Three Months
	Ended March 31,								Ended March 31,
	2024					2024				2023
	(in millions)								(in millions)
Cash flows from operating activities:	Cash flows from operating activities:
Net income
Net income
Net income	Net income	$267	$247	$92			$88
Adjustments to reconcile net income to net cash flows from operating activities:	Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	Depreciation and amortization	208	211
Equity component of allowance for funds used during construction		(43)	(19)
Depreciation and amortization
Depreciation and amortization					90			68

Other

Other

Other	Other	5	23	(11)			(12)
Other changes in assets and liabilities:	Other changes in assets and liabilities:

Gas stored underground

Gas stored underground

Gas stored underground					9			35
Derivative assets	Derivative assets	55	(66)	Derivative assets	12			46
Regulatory assets	Regulatory assets	(16)	(120)	Regulatory assets	29			(37)
Accounts payable	Accounts payable	(55)	5	Accounts payable	15			(48)

Derivative liabilities				Derivative liabilities	(4)			28
Regulatory liabilities	Regulatory liabilities	(37)	28	Regulatory liabilities	(18)			(35)

Other

Other

Other	Other	53	(30)	27			52
Net cash flows from operating activities	Net cash flows from operating activities	437	279	Net cash flows from operating activities	241			185
Cash flows used for investing activities:	Cash flows used for investing activities:
Construction and acquisition expenditures	Construction and acquisition expenditures	(774)	(604)
Proceeds from sales of partial ownership interest in West Riverside		120	—
Construction and acquisition expenditures
Construction and acquisition expenditures					(225)			(316)
Proceeds from sale of partial ownership interest in West Riverside				Proceeds from sale of partial ownership interest in West Riverside	—			25
Other	Other	(26)	(8)	Other	12			(4)
Net cash flows used for investing activities	Net cash flows used for investing activities	(680)	(612)	Net cash flows used for investing activities	(213)			(295)
Cash flows from financing activities:
Cash flows from (used for) financing activities:
Common stock dividends
Common stock dividends
Common stock dividends	Common stock dividends	(138)	(133)	(49)			(46)
Capital contributions from parent	Capital contributions from parent	245	420	Capital contributions from parent	55			180
Proceeds from issuance of long-term debt	Proceeds from issuance of long-term debt	297	588	Proceeds from issuance of long-term debt	297			297

Net change in commercial paper	Net change in commercial paper	(170)	(236)
Contributions from noncontrolling interest		—	29
Distributions to noncontrolling interest		—	(29)
Net change in commercial paper
Net change in commercial paper					(318)			(230)

Other	Other	20	(9)
Net cash flows from financing activities		254	630

Other

Other					(9)			(10)
Net cash flows from (used for) financing activities				Net cash flows from (used for) financing activities	(24)			191
Net increase in cash, cash equivalents and restricted cash	Net increase in cash, cash equivalents and restricted cash	11	297	Net increase in cash, cash equivalents and restricted cash	4			81
Cash, cash equivalents and restricted cash at beginning of period	Cash, cash equivalents and restricted cash at beginning of period	5	2	Cash, cash equivalents and restricted cash at beginning of period	7			5
Cash, cash equivalents and restricted cash at end of period	Cash, cash equivalents and restricted cash at end of period	$16	$299	Cash, cash equivalents and restricted cash at end of period	$11			$86
Supplemental cash flows information:	Supplemental cash flows information:
Cash paid during the period for:	Cash paid during the period for:
Cash paid during the period for:
Cash paid during the period for:
Interest	Interest	($106)	($78)
Income taxes, net		($63)	($51)
Interest
Interest					($40)			($40)

Significant non-cash investing and financing activities:
Significant non-cash investing and financing activities:
Significant non-cash investing and financing activities:	Significant non-cash investing and financing activities:
Accrued capital expenditures	Accrued capital expenditures	$172	$355
Accrued capital expenditures
Accrued capital expenditures					$91			$152

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.


			11

Table of Contents

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

NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. 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 ~~2022~~2023 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 ~~nine~~three months ended ~~September 30, 2023~~March 31, 2024 are not necessarily indicative of results that may be expected for the year ending December 31, ~~2023.~~2024.

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 1(b) Cash and Cash Equivalents -~~ At September 30, 2023, Alliant Energy’s, IPL’s and WPL’s cash and cash equivalents included $189 million, $180 million and $9 million of money market fund investments, respectively, with weighted average interest rates of 5%.

NOTE 2. REGULATORY MATTERS

Regulatory Assets and Regulatory Liabilities -

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

Alliant Energy IPL WPL
September 30,
2023 December 31,
2022 September 30,
2023 December 31,
2022 September 30,
2023 December 31,
2022
Tax-related $919 $929 $825 $848 $94 $81
Pension and OPEB costs 371 392 187 197 184 195
Assets retired early 282 70 267 53 15 17
Asset retirement obligations (AROs) 199 151 155 110 44 41
Commodity cost recovery 138 160 11 1 127 159
Derivatives 72 84 27 48 45 36
IPL’s Duane Arnold Energy Center PPA amendment 48 66 48 66 — —
WPL’s Western Wisconsin gas distribution expansion investments 46 48 — — 46 48
Other 194 146 70 63 124 83
$2,269 $2,046 $1,590 $1,386 $679 $660

~~Tax-related -~~ ~~Refer to~~ ~~Note 9~~ ~~for discussion of Iowa Tax Reform, which resulted in a decrease in Alliant Energy’s and IPL’s tax-related regulatory assets in the third quarter of 2023.~~

~~Assets retired early and Asset retirement obligations -~~ In May 2023, IPL retired the coal-fired Lansing Generating Station and reclassified the remaining net book value of this EGU from property, plant and equipment to a regulatory asset (assets retired early) on Alliant Energy’s and IPL’s balance sheets. The related regulatory asset balance as of September 30, 2023 was $221 million, which is currently included in IPL’s rate base and IPL is earning a return of and a return on the remaining balance. In September 2023, the Federal Energy Regulatory Commission approved continued recovery of the remaining net book value of Lansing from IPL’s wholesale customers. IPL’s retail electric rate review for the October 2024 through September 2025 forward-looking Test Period includes a request for continued recovery of the remaining net book value of Lansing through 2037. In addition, IPL reclassified the remaining net book value of the associated AROs from property, plant and equipment to a regulatory asset (AROs) on Alliant Energy’s and IPL’s balance sheets.


	Alliant Energy		IPL		WPL
	March 31, 2024	December 31, 2023	March 31, 2024	December 31, 2023	March 31, 2024	December 31, 2023
Tax-related	$939	$934	$839	$831	$100	$103
Pension and OPEB costs	340	347	168	171	172	176
Assets retired early	267	273	253	259	14	14
Asset retirement obligations (AROs)	200	194	165	160	35	34
Commodity cost recovery	100	120	5	12	95	108
Derivatives	97	102	33	34	64	68
WPL’s Western Wisconsin gas distribution expansion investments	44	44	—	—	44	44
IPL’s Duane Arnold Energy Center PPA amendment	36	42	36	42	—	—


Other	197	205	68	68	129	137
	$2,220	$2,261	$1,567	$1,577	$653	$684

Derivatives - Refer to Note 111 0 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the ~~nine~~three months ended ~~September 30, 2023,~~March 31, 2024, which resulted in comparable changes to regulatory assets/liabilities on the balance sheets.


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


		Alliant Energy		IPL		WPL
		September 30, 2023	December 31, 2022	September 30, 2023	December 31, 2022	September 30, 2023	December 31, 2022
	Alliant Energy											Alliant Energy				IPL				WPL
	March 31, 2024									March 31, 2024			December 31, 2023		March 31, 2024			December 31, 2023		March 31, 2024		December 31, 2023
Tax-related	Tax-related	$569	$579	$301	$303	$268	$276	Tax-related	$563		$566			$297			$299		$266		$267
Cost of removal obligations	Cost of removal obligations	397	398	249	259	148	139	Cost of removal obligations	380		366			241			242		139		124
Derivatives	Derivatives	91	210	52	115	39	95	Derivatives	49		65			28			34		21		31
Commodity cost recovery	Commodity cost recovery	41	40	11	38	30	2	Commodity cost recovery	61		48			25			13		36		35
WPL’s West Riverside liquidated damages		9	32	—	—	9	32
Electric transmission cost recovery		6	20	6	10	—	10

Other	Other	74	45	36	29	38	16
		$1,187	$1,324	$655	$754	$532	$570

Other

Other									83		85			57			56		26		29
	$1,136									$1,136			$1,130		$648			$644		$488		$486

~~WPL’s West Riverside liquidated damages -~~ Pursuant to PSCW authorization, WPL’s amortization of liquidated damages related to West Riverside construction procurement contracts was used to offset increases in WPL’s retail electric 2022/2023 Test Period revenue requirement, which resulted in decreases in regulatory liabilities on Alliant Energy’s and WPL’s balance sheets and decreases in depreciation and amortization expenses in Alliant Energy’s and WPL’s income statements for the three and nine months ended September 30, 2023.


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NOTE 3. PROPERTY, PLANT AND EQUIPMENT

WPL currently expects construction costs associated with its approximately 1,100 MW of new solar generation will exceed the construction cost estimates previously approved by the PSCW by approximately $180 million. In February 2024, the PSCW issued an order approving deferral of the incremental solar generation construction costs. The PSCW’s order did not authorize a deferral for the return on such costs. In March ~~2023~~2024, WPL filed for judicial review of the PSCW’s retail electric rate review order (2024/2025 forward-looking Test Period) and ~~June 2023, Madison Gas~~solar generation construction cost deferral order related to the recovery and ~~Electric Company~~deferral of the return on the incremental solar generation construction costs in 2024 and ~~WEC~~2025. Alliant Energy ~~Group, Inc., respectively, acquired partial ownership interests in West Riverside. The related proceeds are included in “Proceeds from sales~~and WPL concluded that there was not a probable disallowance of ~~partial ownership interest in West Riverside” in investing activities in Alliant Energy’s~~anticipated higher rate base amounts as of March 31, 2024 given construction costs were reasonably and ~~WPL’s cash flows statements for the nine months ended September 30, 2023. As a result of these transactions, WPL’s undivided current ownership interest in West Riverside is 73.8%.~~prudently incurred.

NOTE 4. RECEIVABLES

~~NOTE 4(a) - Accounts Receivable -~~ ~~For the three and nine months ended September 30, 2023, Alliant Energy’s, IPL’s and WPL’s gross write-offs for accounts receivable were as follows (in millions):~~

Originated in 2022 Originated in 2023
Three Months Nine Months Three Months Nine Months
Alliant Energy $3 $11 $6 $8
IPL 2 7 4 5
WPL 1 4 2 3

~~NOTE 4(b) -~~ 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. In March ~~2023,~~2024, IPL amended and extended through March ~~2024~~2026 the purchase commitment from the third party to which it sells its receivables. ~~The limit on cash proceeds fluctuates between $5 million and $110 million, which IPL may change periodically throughout the year.~~ The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of ~~September 30, 2023,~~March 31, 2024, IPL had ~~$109~~$92 million of 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 ~~and nine~~ months ended ~~September 30~~March 31 were as follows (in millions):


		Three Months		Nine Months
		2024
		2023	2022	2023	2022
		2024

		2024
Maximum outstanding aggregate cash proceeds
Maximum outstanding aggregate cash proceeds
Maximum outstanding aggregate cash proceeds	Maximum outstanding aggregate cash proceeds	$94	$36	$110	$66
Average outstanding aggregate cash proceeds	Average outstanding aggregate cash proceeds	46	3	68	8
Average outstanding aggregate cash proceeds
Average outstanding aggregate cash proceeds

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


		September 30, 2023	December 31, 2022
	March 31, 2024					March 31, 2024		December 31, 2023
Customer accounts receivable	Customer accounts receivable	$161	$145	Customer accounts receivable	$125		$130
Unbilled utility revenues	Unbilled utility revenues	88	132	Unbilled utility revenues	89		98
Other receivables	Other receivables	1	—	Other receivables	1		1
Receivables sold to third party	Receivables sold to third party	250	277	Receivables sold to third party	215		229
Less: cash proceeds	Less: cash proceeds	1	80	Less: cash proceeds	18		1
Deferred proceeds	Deferred proceeds	249	197	Deferred proceeds	197		228
Less: allowance for expected credit losses	Less: allowance for expected credit losses	13	12	Less: allowance for expected credit losses	13		12
Fair value of deferred proceeds	Fair value of deferred proceeds	$236	$185	Fair value of deferred proceeds	$184		$216


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~~Table~~ of ~~Contents~~

As of ~~September 30, 2023,~~March 31, 2024, outstanding receivables past due under the Receivables Agreement were ~~$18~~$22 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three ~~and nine~~ months ended ~~September 30~~March 31 were as follows (in millions):


		Three Months		Nine Months
		2024
		2023	2022	2023	2022
		2024

		2024
Collections
Collections
Collections	Collections	$616	$670	$1,720	$1,731
Write-offs, net of recoveries	Write-offs, net of recoveries	5	3	9	6
Write-offs, net of recoveries
Write-offs, net of recoveries

Effective ~~October 2023,~~April 2024, the limit on cash proceeds under the Receivables Agreement is $5$80 million.

NOTE 5. INVESTMENTS

Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three ~~and nine~~ months ended ~~September 30~~March 31 was as follows (in millions):


		Three Months		Nine Months
		2024
		2023	2022	2023	2022
		2024

		2024
ATC Holdings
ATC Holdings
ATC Holdings	ATC Holdings	($12)	($7)	($37)	($29)

Other	Other	(2)	2	(8)	(8)
		($14)	($5)	($45)	($37)

Other

Other
		($15)
		($15)
		($15)

NOTE 6. COMMON EQUITY

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


Shares outstanding, January 1, ~~2023~~2024			~~251,134,966~~256,096,848
~~At-the-market offering program~~			~~3,569,937~~

Shareowner Direct Plan			~~339,850~~127,917
Equity-based compensation plans			~~134,334~~154,267

Shares outstanding, ~~September 30, 2023~~March 31, 2024			~~255,179,087~~256,379,032


			13

~~At-the-Market Offering Program -~~ ~~In December 2022, Alliant Energy filed a prospectus supplement under which it may sell up to $225 million~~ Table of its common stock through an at-the-market offering program. As of September 30, 2023, Alliant Energy issued 3,569,937 shares of common stock through this program and received cash proceeds of $183 million, net of $2 million in commissions and fees. The proceeds from the issuances of common stock were used for general corporate purposes. Contents

Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy Total Alliant Energy Common Equity
Accumulated Shares in
Additional Other Deferred
Common Paid-In Retained Comprehensive Compensation Noncontrolling Total
Stock Capital Earnings Income Trust Interest Equity
Three Months Ended September 30, 2023
Beginning balance, June 30, 2023 $3 $2,854 $3,606 $3 ($14) $— $6,452
Net income attributable to Alliant Energy common shareowners 259 259
Common stock dividends ($0.4525 per share) (115) (115)
At-the-market offering program and Shareowner Direct Plan issuances 125 125
Equity-based compensation plans and other 3 1 4
Other comprehensive income, net of tax 1 1
Ending balance, September 30, 2023 $3 $2,982 $3,750 $4 ($13) $— $6,726
Three Months Ended September 30, 2022
Beginning balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166
Net income attributable to Alliant Energy common shareowners 227 227
Common stock dividends ($0.4275 per share) (106) (106)
Shareowner Direct Plan issuances 6 6
Equity-based compensation plans and other 2 (1) 1
Distributions to noncontrolling interest (29) (29)
Ending balance, September 30, 2022 $3 $2,767 $3,508 $— ($13) $— $6,265



Alliant Energy				Accumulated	Shares in
		Additional		Other	Deferred	Total
	Common	Paid-In	Retained	Comprehensive	Compensation	Common
	Stock	Capital	Earnings	Income (Loss)	Trust	Equity
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 shareowners			158			158
Common stock dividends ($0.48 per share)			(123)			(123)
Shareowner Direct Plan issuances		6				6
Equity-based compensation plans and other		(3)			1	(2)



Other comprehensive income, net of tax				1		1
Ending balance, March 31, 2024	$3	$3,033	$3,791	$2	($12)	$6,817
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$3	$2,777	$3,509	$—	($13)	$6,276
Net income attributable to Alliant Energy common shareowners			163			163
Common stock dividends ($0.4525 per share)			(113)			(113)
Shareowner Direct Plan issuances		6				6
Equity-based compensation plans and other		(3)				(3)



Other comprehensive loss, net of tax				(1)		(1)
Ending balance, March 31, 2023	$3	$2,780	$3,559	($1)	($13)	$6,328



IPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2024
Beginning balance, December 31, 2023	$33	$2,887	$1,054	$3,974
Net income			63	63
Common stock dividends			(50)	(50)
Capital contributions from parent		50		50
Ending balance, March 31, 2024	$33	$2,937	$1,067	$4,037
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$33	$2,807	$968	$3,808
Net income			72	72
Common stock dividends			(70)	(70)

Ending balance, March 31, 2023	$33	$2,807	$970	$3,810



WPL		Additional		Total
	Common	Paid-In	Retained	Common
	Stock	Capital	Earnings	Equity
Three Months Ended March 31, 2024
Beginning balance, December 31, 2023	$66	$2,478	$1,353	$3,897
Net income			92	92
Common stock dividends			(49)	(49)
Capital contributions from parent		55		55



Ending balance, March 31, 2024	$66	$2,533	$1,396	$3,995
Three Months Ended March 31, 2023
Beginning balance, December 31, 2022	$66	$2,233	$1,192	$3,491
Net income			88	88
Common stock dividends			(46)	(46)
Capital contributions from parent		180		180



Ending balance, March 31, 2023	$66	$2,413	$1,234	$3,713


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Table of Contents

Alliant Energy Total Alliant Energy Common Equity
Accumulated Shares in
Additional Other Deferred
Common Paid-In Retained Comprehensive Compensation Noncontrolling Total
Stock Capital Earnings Income Trust Interest Equity
Nine Months Ended September 30, 2023
Beginning balance, December 31, 2022 $3 $2,777 $3,509 $— ($13) $— $6,276
Net income attributable to Alliant Energy common shareowners 582 582
Common stock dividends ($1.3575 per share) (341) (341)
At-the-market offering program and Shareowner Direct Plan issuances 201 201
Equity-based compensation plans and other 4 4
Other comprehensive income, net of tax 4 4
Ending balance, September 30, 2023 $3 $2,982 $3,750 $4 ($13) $— $6,726
Nine Months Ended September 30, 2022
Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990
Net income attributable to Alliant Energy common shareowners 579 579
Common stock dividends ($1.2825 per share) (322) (322)
Shareowner Direct Plan issuances 19 19
Equity-based compensation plans and other (1) 1 (1) (1)
Contributions from noncontrolling interest 29 29
Distributions to noncontrolling interest (29) (29)
Ending balance, September 30, 2022 $3 $2,767 $3,508 $— ($13) $— $6,265

IPL Additional Total
Common Paid-In Retained Common
Stock Capital Earnings Equity
Three Months Ended September 30, 2023
Beginning balance, June 30, 2023 $33 $2,847 $989 $3,869
Net income 170 170
Common stock dividends (70) (70)
Capital contributions from parent 20 20
Ending balance, September 30, 2023 $33 $2,867 $1,089 $3,989
Three Months Ended September 30, 2022
Beginning balance, June 30, 2022 $33 $2,807 $942 $3,782
Net income 154 154
Common stock dividends (80) (80)
Ending balance, September 30, 2022 $33 $2,807 $1,016 $3,856

IPL Additional Total
Common Paid-In Retained Common
Stock Capital Earnings Equity
Nine Months Ended September 30, 2023
Beginning balance, December 31, 2022 $33 $2,807 $968 $3,808
Net income 331 331
Common stock dividends (210) (210)
Capital contributions from parent 60 60
Ending balance, September 30, 2023 $33 $2,867 $1,089 $3,989
Nine Months Ended September 30, 2022
Beginning balance, December 31, 2021 $33 $2,807 $929 $3,769
Net income 327 327
Common stock dividends (240) (240)
Ending balance, September 30, 2022 $33 $2,807 $1,016 $3,856


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~~Table~~ of ~~Contents~~

WPL Total WPL Common Equity
Additional
Common Paid-In Retained Noncontrolling Total
Stock Capital Earnings Interest Equity
Three Months Ended September 30, 2023
Beginning balance, June 30, 2023 $66 $2,413 $1,260 $— $3,739
Net income 107 107
Common stock dividends (46) (46)
Capital contributions from parent 65 65
Ending balance, September 30, 2023 $66 $2,478 $1,321 $— $3,865
Three Months Ended September 30, 2022
Beginning balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183
Net income 91 91
Common stock dividends (44) (44)
Capital contributions from parent 155 155
Distributions to noncontrolling interest (29) (29)
Ending balance, September 30, 2022 $66 $2,123 $1,167 $— $3,356

WPL Total WPL Common Equity
Additional
Common Paid-In Retained Noncontrolling Total
Stock Capital Earnings Interest Equity
Nine Months Ended September 30, 2023
Beginning balance, December 31, 2022 $66 $2,233 $1,192 $— $3,491
Net income 267 267
Common stock dividends (138) (138)
Capital contributions from parent 245 245
Ending balance, September 30, 2023 $66 $2,478 $1,321 $— $3,865
Nine Months Ended September 30, 2022
Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823
Net income 247 247
Common stock dividends (133) (133)
Capital contributions from parent 420 420
Contributions from noncontrolling interest 29 29
Distributions to noncontrolling interest (29) (29)
Other (1) (1)
Ending balance, September 30, 2022 $66 $2,123 $1,167 $— $3,356

NOTE 7. DEBT

NOTE 7(a) Short-term Debt - In March ~~2023,~~2024, Alliant Energy, IPL and WPL ~~extended their single credit facility agreement, which currently expires in December 2027, and~~ reallocated credit facility capacity amounts to ~~$450~~$500 million for Alliant Energy at the parent company level, ~~$250~~$200 million for IPL and $300 million for WPL, within the $1 billion total commitment. Information regarding ~~Alliant Energy’s, IPL’s and WPL’s~~ commercial paper classified as short-term debt was as follows (dollars in millions):


September 30, 2023		Alliant Energy	IPL	WPL
March 31, 2024					March 31, 2024	Alliant Energy	IPL		WPL
Amount outstanding	Amount outstanding	$451	$—	$120	Amount outstanding	$334		$—
Weighted average interest rates	Weighted average interest rates	5.5%	—%	5.4%	Weighted average interest rates	5.5%		—%
Available credit facility capacity	Available credit facility capacity	$549	$250	$180	Available credit facility capacity	$666	$200		$300

Alliant Energy IPL WPL
Three Months Ended September 30 2023 2022 2023 2022 2023 2022
Maximum amount outstanding (based on daily outstanding balances) $474 $449 $7 $— $125 $251
Average amount outstanding (based on daily outstanding balances) $440 $353 $— $— $86 $110
Weighted average interest rates 5.5% 2.4% 5.5% —% 5.4% 2.0%
Nine Months Ended September 30
Maximum amount outstanding (based on daily outstanding balances) $793 $577 $70 $— $349 $252
Average amount outstanding (based on daily outstanding balances) $367 $377 $2 $— $135 $160
Weighted average interest rates 5.1% 1.2% 5.3% —% 4.9% 0.9%


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~~Table~~ of ~~Contents~~

In January 2023, AEF received $50 million of proceeds from its December 2022 term loan credit agreement, which was classified as “Other short-term borrowings” on Alliant Energy’s balance sheet as of September 30, 2023.


	Alliant Energy		IPL		WPL
Three Months Ended March 31	2024	2023	2024	2023	2024	2023
Maximum amount outstanding (based on daily outstanding balances)	$632	$793	$14	$—	$390	$349
Average amount outstanding (based on daily outstanding balances)	$487	$574	$1	$—	$255	$304
Weighted average interest rates	5.5%	4.8%	5.5%	—%	5.5%	4.8%

NOTE 7(b) Long-term Debt - In ~~September 2023, IPL issued~~March 2024, AEF entered into a $300 million variable rate (6% as of ~~5.70% senior debentures due 2033. The net proceeds from IPL’s issuance were used~~March 31, 2024) term loan credit agreement (with Alliant Energy as guarantor), which expires in March 2025. This term loan credit agreement amends and restates the term loan credit agreement that expired in March 2024, and retired the $300 million variable rate term loan set forth therein. AEF’s restated term loan credit agreement includes an option to ~~reduce cash amounts received from its sales of accounts receivable program, reduce commercial paper classified as long-term debt, for general corporate purposes and/~~increase the amount outstanding with one or ~~were placed~~more additional term loans in ~~money market fund investments. In June 2023, AEF retired its $400 million 3.75% senior notes.~~an aggregate amount not to exceed $100 million. In March ~~2023,~~2024, WPL issued $300 million of ~~4.95%~~5.375% debentures due ~~2033.~~2034. WPL’s debentures were issued as green bonds, and an amount equal to or in excess of the net proceeds ~~were~~will be allocated or disbursed for the development and acquisition of ~~its~~WPL’s solar EGUs.

Convertible Senior Notes - In March 2023, Alliant Energy issued $575 million of 3.875% convertible senior notes (the Notes), which are senior unsecured obligations, and used the net proceeds from the issuance for general corporate purposes. The Notes will mature on March 15, 2026 unless earlier converted or repurchased, and no sinking fund is provided for the Notes. Alliant Energy may not redeem the Notes prior to the maturity date. Holders may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding December 15, 2025 only under the following circumstances:

•during any calendar quarter commencing after the calendar quarter ending on June 30, 2023 (and only during such calendar quarter), if the last reported sale price of Alliant Energy’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day during such period;

•during the 5 business day period after any 10 consecutive trading day period (the “measurement period”) in which the trading price (as defined in the related Indenture) per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of Alliant Energy’s common stock and the conversion rate on each such trading day; or

•~~upon the occurrence of specified corporate events.~~

On or after December 15, 2025 until the close of business on the business day immediately preceding the maturity date, holders may convert all or any portion of their Notes at any time, regardless of the foregoing circumstances. Upon conversion of the Notes, Alliant Energy will pay cash up to the aggregate principal amount of the Notes to be converted and pay or deliver, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted.

The initial conversion rate is 15.5461 shares of common stock per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $64.32 per share of Alliant Energy’s common stock). The conversion rate is subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date, Alliant Energy will, in certain circumstances, increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event.

If Alliant Energy undergoes a fundamental change (as defined in the related Indenture), then, subject to certain conditions, holders of the Notes may require Alliant Energy to repurchase for cash all or any portion of its Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

As of ~~September 30, 2023,~~March 31, 2024, the conditions allowing holders of ~~the Notes~~Alliant Energy’s convertible senior notes due 2026 (the Notes) to convert their Notes were not met, and as a result, the Notes were classified as “Long-term debt, net” on Alliant Energy’s balance sheet. As of ~~September 30, 2023,~~March 31, 2024, the net carrying amount of the Notes was ~~$567~~$569 million, with unamortized debt issuance costs of $8$6 million, and the estimated fair value (Level 2) of the Notes was ~~$556~~$567 million. As of ~~September 30, 2023,~~March 31, 2024, 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.


			17

~~Table~~ of ~~Contents~~

NOTE 8. REVENUES

Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):


		Alliant Energy		IPL		WPL
Three Months Ended September 30		2023	2022	2023	2022	2023	2022
	Alliant Energy											Alliant Energy				IPL				WPL
Three Months Ended March 31								Three Months Ended March 31	2024		2023			2024			2023		2024			2023
Electric Utility:	Electric Utility:
Retail - residential
Retail - residential
Retail - residential	Retail - residential	$374	$376	$209	$222	$165	$154	$297		$285			$150		$143			$147			$142
Retail - commercial	Retail - commercial	241	243	158	165	83	78	Retail - commercial	186		185			114			112		72			73
Retail - industrial	Retail - industrial	280	289	153	172	127	117	Retail - industrial	223		216			112			107		111			109
Wholesale	Wholesale	59	68	21	19	38	49	Wholesale	47		46			13			12		34			34
Bulk power and other	Bulk power and other	41	63	10	18	31	45	Bulk power and other	38		36			3			14		35			22
Total Electric Utility	Total Electric Utility	995	1,039	551	596	444	443	Total Electric Utility	791		768			392			388		399			380
Gas Utility:	Gas Utility:
Retail - residential	Retail - residential	23	28	14	14	9	14
Retail - residential
Retail - residential									126		167			68			93		58			74
Retail - commercial	Retail - commercial	12	18	9	8	3	10	Retail - commercial	61		88			30			44		31			44
Retail - industrial	Retail - industrial	2	4	2	3	—	1	Retail - industrial	5		7			3			4		2			3
Transportation/other	Transportation/other	10	12	6	8	4	4	Transportation/other	13		14			7			9		6			5
Total Gas Utility	Total Gas Utility	47	62	31	33	16	29	Total Gas Utility	205		276			108			150		97			126
Other Utility:	Other Utility:
Steam	Steam	11	9	11	9	—	—
Steam
Steam									12		10			12			10		—			—
Other utility	Other utility	2	2	1	2	1	—	Other utility	1		1			1			1		—			—
Total Other Utility	Total Other Utility	13	11	12	11	1	—	Total Other Utility	13		11			13			11		—			—
Non-Utility and Other:	Non-Utility and Other:
Travero and other	Travero and other	22	23	—	—	—	—
Travero and other
Travero and other									22		22			—			—		—			—

Total Non-Utility and Other	Total Non-Utility and Other	22	23	—	—	—	—
Total Non-Utility and Other
Total Non-Utility and Other									22		22			—			—		—			—
Total revenues	Total revenues	$1,077	$1,135	$594	$640	$461	$472	Total revenues	$1,031		$1,077			$513			$549		$496			$506

Alliant Energy IPL WPL
Nine Months Ended September 30 2023 2022 2023 2022 2023 2022
Electric Utility:
Retail - residential $943 $956 $503 $529 $440 $427
Retail - commercial 627 628 399 411 228 217
Retail - industrial 740 743 389 418 351 325
Wholesale 154 168 47 49 107 119
Bulk power and other 98 129 32 31 66 98
Total Electric Utility 2,562 2,624 1,370 1,438 1,192 1,186
Gas Utility:
Retail - residential 233 237 131 127 102 110
Retail - commercial 122 127 65 62 57 65
Retail - industrial 12 15 8 10 4 5
Transportation/other 33 39 20 25 13 14
Total Gas Utility 400 418 224 224 176 194
Other Utility:
Steam 32 29 32 29 — —
Other utility 6 6 4 5 2 1
Total Other Utility 38 35 36 34 2 1
Non-Utility and Other:
Travero and other 66 70 — — — —
Total Non-Utility and Other 66 70 — — — —
Total revenues $3,066 $3,147 $1,630 $1,696 $1,370 $1,381


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Table of Contents

NOTE 9. INCOME TAXES

Income Tax Rates - Overall effective income tax rates for the three ~~and nine~~ months ended ~~September 30,~~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, amortization of excess deferred taxes and the effect of rate-making on property-related differences.


			18

~~Table~~ of ~~Contents~~

Alliant Energy IPL WPL
Three Months Nine Months Three Months Nine Months Three Months Nine Months
2023 2022 2023 2022 2023 2022 2023 2022 2023 2022 2023 2022
Overall income tax rate 2% 6% 1% 4% (22%) (12%) (20%) (14%) 16% 15% 15% 17%


	Alliant Energy		IPL	WPL

	2024	2023		2024	2023	2024	2023
Overall income tax rate	(7%)	(1%)		(19%)	(18%)	6%	12%

Deferred Tax Assets and Liabilities -

Carryforwards - At ~~September 30, 2023,~~March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):

Range of Expiration Dates Alliant Energy IPL WPL
State net operating losses 2025-2043 $431 $6 $1
Federal tax credits 2031-2043 737 520 208

~~Iowa Tax Reform~~ - Pursuant to Iowa tax reform enacted in 2022, in September 2023, the Iowa Department of Revenue announced an Iowa corporate income tax rate of 7.1%, effective January 1, 2024. Deferred tax assets and liabilities are measured at the enacted tax rate expected to be applied when temporary differences are to be realized or settled. Given the announcement of the new Iowa corporate income tax rate, Alliant Energy’s and IPL’s deferred tax liabilities were remeasured based upon the new rate effective January 1, 2024, which resulted in a $73 million reduction of Alliant Energy’s and IPL’s tax-related regulatory assets and a corresponding decrease in their deferred tax liabilities in the third quarter of 2023. The reduction in tax-related regulatory assets is expected to provide cost benefits to IPL’s customers in the future. Alliant Energy parent company’s deferred tax assets were remeasured based upon the new rate effective January 1, 2024, which resulted in a charge of $8 million recorded to income tax expense in Alliant Energy’s income statement and an increase in deferred tax liabilities on Alliant Energy’s balance sheet in the third quarter of 2023. Based on the remeasurement of Alliant Energy parent company’s deferred tax assets in the third quarter of 2022 for the Iowa corporate income tax rate of 8.4% effective January 1, 2023, a charge of $8 million was recorded to income tax expense in Alliant Energy’s income statement in the third quarter of 2022. Alliant Energy is currently unable to predict with certainty the timing or amount of any future rate reductions.


	Range of Expiration Dates	Alliant Energy	IPL	WPL

State net operating losses	2025-2044	$403	$6	$1
Federal tax credits	2032-2044	685	462	214

NOTE 10. BENEFIT PLANS

NOTE 10(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 ~~and nine~~ months ended ~~September 30~~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.


		Defined Benefit Pension Plans				OPEB Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans								OPEB Plans
		Three Months		Nine Months		Three Months		Nine Months
Alliant Energy	Alliant Energy	2023	2022	2023	2022	2023	2022	2023	2022
Alliant Energy
Alliant Energy
Service cost
Service cost
Service cost	Service cost	$2	$3	$4	$7	$1	$—	$2	$2
Interest cost	Interest cost	12	9	35	27	3	1	7	4
Interest cost
Interest cost
Expected return on plan assets	Expected return on plan assets	(14)	(18)	(40)	(52)	(2)	—	(4)	(3)
Amortization of prior service credit		(1)	—	(1)	—	—	—	—	—
Expected return on plan assets
Expected return on plan assets

Amortization of actuarial loss

Amortization of actuarial loss

Amortization of actuarial loss	Amortization of actuarial loss	7	8	21	24	—	1	1	2

		$5
		$6	$2	$19	$6	$2	$2	$6	$5

		$5

		$5


		Defined Benefit Pension Plans				OPEB Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans								OPEB Plans
		Three Months		Nine Months		Three Months		Nine Months
IPL	IPL	2023	2022	2023	2022	2023	2022	2023	2022
IPL
IPL
Service cost
Service cost
Service cost	Service cost	$—	$1	$2	$4	$—	$—	$—	$1
Interest cost	Interest cost	6	4	16	12	1	1	3	2
Interest cost
Interest cost
Expected return on plan assets
Expected return on plan assets
Expected return on plan assets	Expected return on plan assets	(6)	(7)	(19)	(23)	(1)	(1)	(3)	(3)

Amortization of actuarial loss	Amortization of actuarial loss	2	3	8	10	—	—	1	—
		$2	$1	$7	$3	$—	$—	$1	$—
Amortization of actuarial loss

Amortization of actuarial loss
		$1
		$1
		$1


		Defined Benefit Pension Plans				OPEB Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans
		Defined Benefit Pension Plans								OPEB Plans
		Three Months		Nine Months		Three Months		Nine Months
WPL	WPL	2023	2022	2023	2022	2023	2022	2023	2022
Service cost		$—	$—	$1	$2	$1	$—	$1	$—
WPL
WPL

Interest cost	Interest cost	5	4	15	12	1	1	3	2

Interest cost

Interest cost
Expected return on plan assets
Expected return on plan assets
Expected return on plan assets	Expected return on plan assets	(5)	(7)	(16)	(23)	(1)	—	(1)	—

Amortization of actuarial loss	Amortization of actuarial loss	3	4	10	12	—	—	—	1

Amortization of actuarial loss
		$3	$1	$10	$3	$1	$1	$3	$3
Amortization of actuarial loss

		$2

		$2

		$2


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~~Table~~ of ~~Contents~~

NOTE 10(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 ~~and nine~~ months ended ~~September 30~~March 31 was as follows (in millions):


		Alliant Energy
		Alliant Energy
		Alliant Energy												IPL	WPL
		Alliant Energy				IPL				WPL
		Three Months		Nine Months		Three Months		Nine Months		Three Months		Nine Months
		2023	2022	2023	2022	2023	2022	2023	2022	2023	2022	2023	2022
		2024
		2024
		2024
Compensation expense
Compensation expense
Compensation expense	Compensation expense	$4	$3	$10	$9	$2	$2	$5	$5	$2	$1	$4	$4
Income tax benefits	Income tax benefits	1	1	3	3	1	—	1	1	—	—	1	1
Income tax benefits
Income tax benefits

As of ~~September 30, 2023,~~March 31, 2024, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $22 million, $11 million ~~$6 million~~ and $5$10 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.


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For the ~~nine~~three months ended ~~September 30, 2023,~~March 31, 2024, performance shares ~~performance restricted stock units~~ and restricted stock units were granted to key employees under ~~existing~~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
Grants Grant Date Fair Value
Performance shares 108,513 $55.68
Performance restricted stock units 123,990 52.71
Restricted stock units 105,982 52.77


		Weighted Average
	Grants	Grant Date Fair Value
Performance shares (total shareowner return metric)	123,098	$46.04
Performance shares (net income and diversity metrics) (formerly granted as performance restricted stock units)	140,683	48.40
Restricted stock units	120,557	48.40

As of ~~September 30, 2023, 274,960~~March 31, 2024, 242,680 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

NOTE 11. DERIVATIVE INSTRUMENTS

Commodity Derivatives -

Notional Amounts - As of ~~September 30, 2023,~~March 31, 2024, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):


		Electricity		FTRs		Natural Gas		Coal
		MWhs	Years	MWhs	Years	Dths	Years	Tons	Years
		Electricity
		Electricity
		Electricity
		MWhs
		MWhs
		MWhs
Alliant Energy
Alliant Energy
Alliant Energy	Alliant Energy	1,661	2023-2026	18,122	2023-2024	180,519	2023-2032	370	2023
IPL	IPL	746	2023-2026	8,078	2023-2024	85,457	2023-2030	217	2023
IPL
IPL
WPL	WPL	915	2023-2026	10,044	2023-2024	95,062	2023-2032	153	2023
WPL
WPL

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 Energy		IPL		WPL
		September 30, 2023	December 31, 2022	September 30, 2023	December 31, 2022	September 30, 2023	December 31, 2022
	Alliant Energy											Alliant Energy				IPL				WPL
	March 31, 2024									March 31, 2024			December 31, 2023		March 31, 2024			December 31, 2023		March 31, 2024		December 31, 2023
Current derivative assets	Current derivative assets	$67	$111	$51	$69	$16	$42	Current derivative assets	$16		$44			$12			$30		$4		$14
Non-current derivative assets	Non-current derivative assets	62	126	34	69	28	57	Non-current derivative assets	40		44			22			24		18		20
Current derivative liabilities	Current derivative liabilities	32	59	15	40	17	19	Current derivative liabilities	49		51			23			22		26		29
Non-current derivative liabilities	Non-current derivative liabilities	34	20	6	6	28	14	Non-current derivative liabilities	45		47			7			8		38		39

During the ~~nine~~three months ended ~~September 30, 2023,~~March 31, 2024, Alliant Energy’s, IPL’s and WPL’s derivative assets decreased primarily due to settlements of FTRs, natural gas ~~FTR~~ and electricity contracts, and lower natural gas prices, partially offset by new FTRs resulting from the annual FTR auction in the second quarter of 2023 operated by MISO. Alliant Energy’s and IPL’s derivative liabilities decreased primarily due to settlement of natural gas contracts.prices. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted 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 ~~September 30, 2023~~March 31, 2024 and December 31, ~~2022,~~2023, 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


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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.


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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 Energy		IPL		WPL
		Gross		Gross		Gross
		(as reported)	Net	(as reported)	Net	(as reported)	Net
September 30, 2023
	Alliant Energy											Alliant Energy				IPL				WPL
	Gross
		(as reported)
		(as reported)
		(as reported)									Net			(as reported)			Net		(as reported)			Net
March 31, 2024
Derivative assets
Derivative assets
Derivative assets	Derivative assets	$129	$108	$85	$73	$44	$35	$56		$26			$34		$17			$22			$9
Derivative liabilities	Derivative liabilities	66	45	21	9	45	36	Derivative liabilities	94		64			30			13		64			51
December 31, 2022
December 31, 2023
Derivative assets
Derivative assets
Derivative assets	Derivative assets	237	193	138	108	99	85	88		47			54		32			34			15
Derivative liabilities	Derivative liabilities	79	35	46	16	33	19	Derivative liabilities	98		57			30			8		68			49

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.

Interest Rate Derivative - ~~In January 2023, AEF entered into a $300 million~~The interest rate derivative associated with AEF’s interest rate swap maturing in January 2026 to mitigate interest rate risk. Under the terms of the swap, AEF exchanged a variable interest rate for a fixed interest rate of 3.93% on a portion of its variable-rate term loan borrowings. The related interest rate derivative was valued based on quoted prices that utilize current market interest rate forecasts. As of ~~September 30, 2023,~~March 31, 2024 $6, $3 million of non-current interest rate derivative assets was recorded in “Deferred charges and other” on Alliant Energy’s balance sheet. This interest rate derivative was designated as a cash flow hedge, with changes in fair value recorded as other comprehensive income/loss. As of ~~September 30, 2023,~~March 31, 2024, accumulated other comprehensive income included $4$2 million of income related to the interest rate swap. For the three ~~and nine~~ months ended ~~September 30,~~ March 31, 2024 and 2023, $1 million and $2$1 million, respectively, of reductions to interest expense were recorded in Alliant Energy’s income statement related to the interest rate swap.

NOTE 12. 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 Energy	Alliant Energy	September 30, 2023						December 31, 2022					Alliant Energy	March 31, 2024				December 31, 2023
				Fair Value					Fair Value
		Carrying		Level	Level	Level		Carrying	Level	Level	Level
		Amount		1	2	3	Total	Amount	1	2	3	Total
			Fair Value																	Fair Value					Fair Value
	Carrying
		Amount
		Amount
		Amount													1	2	3		Total		Amount	1	2	3		Total
Assets:	Assets:
Money market fund investments
Money market fund investments
Money market fund investments	Money market fund investments	$189		$189	$—	$—	$189	$10	$10	$—	$—	$10
Commodity derivatives	Commodity derivatives	129		—	80	49	129	237	—	206	31	237
Interest rate derivatives	Interest rate derivatives	6		—	6	—	6	—	—	—	—	—
Deferred proceeds	Deferred proceeds	236		—	—	236	236	185	—	—	185	185
Liabilities:	Liabilities:
Commodity derivatives	Commodity derivatives	66		—	60	6	66	79	—	67	12	79
Commodity derivatives
Commodity derivatives

Long-term debt (incl. current maturities)	Long-term debt (incl. current maturities)	8,838		—	7,863	—	7,863	8,076	—	7,338	1	7,339
Long-term debt (incl. current maturities)
Long-term debt (incl. current maturities)


IPL	March 31, 2024					December 31, 2023
		Fair Value					Fair Value
	Carrying	Level	Level	Level		Carrying	Level	Level	Level
	Amount	1	2	3	Total	Amount	1	2	3	Total
Assets:
Money market fund investments	$6	$6	$—	$—	$6	$45	$45	$—	$—	$45
Commodity derivatives	34	—	26	8	34	54	—	30	24	54
Deferred proceeds	184	—	—	184	184	216	—	—	216	216
Liabilities:
Commodity derivatives	30	—	27	3	30	30	—	25	5	30
Long-term debt (incl. current maturities)	3,945	—	3,607	—	3,607	3,945	—	3,664	—	3,664


			18			21

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IPL September 30, 2023 December 31, 2022
Fair Value Fair Value
Carrying Level Level Level Carrying Level Level Level
Amount 1 2 3 Total Amount 1 2 3 Total
Assets:
Money market fund investments $180 $180 $— $— $180 $10 $10 $— $— $10
Commodity derivatives 85 — 45 40 85 138 — 111 27 138
Deferred proceeds 236 — — 236 236 185 — — 185 185
Liabilities:
Commodity derivatives 21 — 16 5 21 46 — 35 11 46
Long-term debt 3,944 — 3,422 — 3,422 3,646 — 3,228 — 3,228


WPL	WPL	September 30, 2023						December 31, 2022					WPL	March 31, 2024				December 31, 2023
			Fair Value																	Fair Value					Fair Value
	Carrying
		Amount
		Amount
		Amount													1	2	3		Total		Amount	1	2	3		Total
Assets:
				Fair Value					Fair Value
Commodity derivatives
		Carrying		Level	Level	Level		Carrying	Level	Level	Level
		Amount		1	2	3	Total	Amount	1	2	3	Total
Assets:
Commodity derivatives

Commodity derivatives	Commodity derivatives	$44		$—	$35	$9	$44	$99	$—	$95	$4	$99
Liabilities:	Liabilities:
Commodity derivatives	Commodity derivatives	45		—	44	1	45	33	—	32	1	33
Commodity derivatives
Commodity derivatives
Long-term debt	Long-term debt	3,069		—	2,722	—	2,722	2,770	—	2,542	—	2,542

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

Alliant Energy Commodity Contract Derivative
Assets and (Liabilities), net Deferred Proceeds
Three Months Ended September 30 2023 2022 2023 2022
Beginning balance, July 1 $54 $72 $175 $244
Total net gains (losses) included in changes in net assets (realized/unrealized) 17 (1) — —
Sales (1) — — —
Settlements (a) (27) (26) 61 4
Ending balance, September 30 $43 $45 $236 $248
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 September 30 $17 ($1) $— $—

Alliant Energy Commodity Contract Derivative
Assets and (Liabilities), net Deferred Proceeds
Nine Months Ended September 30 2023 2022 2023 2022
Beginning balance, January 1 $19 $29 $185 $214
Total net gains (losses) included in changes in net assets (realized/unrealized) 6 (17) — —
Purchases 62 79 — —
Sales (2) — — —
Settlements (a) (42) (46) 51 34
Ending balance, September 30 $43 $45 $236 $248
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 September 30 $6 ($17) $— $—


Alliant Energy	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended March 31	2024	2023	2024	2023
Beginning balance, January 1	$24	$19	$216	$185
Total net losses included in changes in net assets (realized/unrealized)	(3)	(4)	—	—




Settlements (a)	(14)	(20)	(32)	(32)
Ending balance, March 31	$7	($5)	$184	$153
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	($3)	($4)	$—	$—

~~Table~~ of ~~Contents~~


IPL	Commodity Contract Derivative
	Assets and (Liabilities), net		Deferred Proceeds
Three Months Ended March 31	2024	2023	2024	2023
Beginning balance, January 1	$19	$16	$216	$185
Total net gains (losses) included in changes in net assets (realized/unrealized)	(4)	1	—	—




Settlements (a)	(10)	(17)	(32)	(32)
Ending balance, March 31	$5	$—	$184	$153
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	($4)	$1	$—	$—

IPL Commodity Contract Derivative
Assets and (Liabilities), net Deferred Proceeds
Three Months Ended September 30 2023 2022 2023 2022
Beginning balance, July 1 $41 $58 $175 $244
Total net gains (losses) included in changes in net assets (realized/unrealized) 12 (6) — —
Sales (1) — — —
Settlements (a) (17) (19) 61 4
Ending balance, September 30 $35 $33 $236 $248
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 September 30 $12 ($6) $— $—

IPL Commodity Contract Derivative
Assets and (Liabilities), net Deferred Proceeds
Nine Months Ended September 30 2023 2022 2023 2022
Beginning balance, January 1 $16 $18 $185 $214
Total net losses included in changes in net assets (realized/unrealized) — (13) — —
Purchases 51 58 — —
Sales (2) — — —
Settlements (a) (30) (30) 51 34
Ending balance, September 30 $35 $33 $236 $248
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 September 30 $— ($14) $— $—


WPL	Commodity Contract Derivative
	Assets and (Liabilities), net
Three Months Ended March 31	2024	2023
Beginning balance, January 1	$5	$3
Total net gains (losses) included in changes in net assets (realized/unrealized)	1	(5)




Settlements	(4)	(3)
Ending balance, March 31	$2	($5)
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	$1	($5)

WPL Commodity Contract Derivative
Assets and (Liabilities), net
Three Months Ended September 30 2023 2022
Beginning balance, July 1 $13 $14
Total net gains included in changes in net assets (realized/unrealized) 5 5
Settlements (10) (7)
Ending balance, September 30 $8 $12
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 $5 $5

WPL Commodity Contract Derivative
Assets and (Liabilities), net
Nine Months Ended September 30 2023 2022
Beginning balance, January 1 $3 $11
Total net gains (losses) included in changes in net assets (realized/unrealized) 6 (4)
Purchases 11 21
Settlements (12) (16)
Ending balance, September 30 $8 $12
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 September 30 $6 ($3)

(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 FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions):

Alliant Energy IPL WPL
Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs
September 30, 2023 $3 $40 $4 $31 ($1) $9
December 31, 2022 (10) 29 (9) 25 (1) 4


	Alliant Energy		IPL		WPL
	Excluding FTRs	FTRs	Excluding FTRs	FTRs	Excluding FTRs	FTRs
March 31, 2024	($1)	$8	($1)	$6	$—	$2
December 31, 2023	3	21	3	16	—	5


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NOTE 13. COMMITMENTS AND CONTINGENCIES

NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of battery storage, IPL’s and WPL’s expansion of solar ~~generation.~~generation, and IPL’s repowering of the existing Franklin County wind farm. At ~~September 30, 2023,~~March 31, 2024, Alliant Energy’s, IPL’s and WPL’s minimum future commitments for these projects were ~~$221~~$191 million, ~~$175~~$80 million and ~~$46~~$111 million, respectively.

NOTE 13(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 ~~September 30, 2023,~~March 31, 2024, 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 Energy	IPL	WPL
	Alliant Energy						Alliant Energy		IPL		WPL
Natural gas	Natural gas	$962	$436	$526	Natural gas	$807		$335		$472
Coal	Coal	188	108	80	Coal	167		110		57

Other (a)	Other (a)	125	52	25
		$1,275	$596	$631
Other (a)
Other (a)						124		52		25
	$1,098						$1,098		$497		$554

(a)Includes individual commitments incurred during the normal course of business that exceeded $1 million at ~~September 30, 2023.~~March 31, 2024.

NOTE 13(c) Guarantees and Indemnifications -

Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee 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.

As of ~~September 30, 2023,~~March 31, 2024, the currently known partnership obligations for the abandonment obligations are estimated at ~~$58~~$49 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the ~~$58~~$49 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to ~~pay; however,~~pay and therefore has not recognized any material liabilities related to this guarantee as of ~~both September 30, 2023~~March 31, 2024 and December 31, 2022, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees.2023.

Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in ~~July~~ 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related guarantees.

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 $51 million as of ~~September 30, 2023~~March 31, 2024 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 ~~September 30, 2023~~March 31, 2024 and December 31, ~~2022.~~2023.

Transfers of Renewable Tax Credits - In 2023, IPL and WPL entered into agreements to transfer renewable tax credits from certain wind, solar and battery storage facilities to other corporate taxpayers in exchange for cash. IPL and WPL provided indemnifications associated with $76 million and $22 million, respectively, of proceeds for renewable tax credits transferred to other corporate taxpayers in 2023 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.


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Table of Contents

NOTE 13(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 ~~September 30, 2023,~~March 31, 2024, 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):


			24

~~Table~~ of ~~Contents~~


		Alliant Energy			IPL			WPL
	Alliant Energy															Alliant Energy					IPL					WPL
Range of estimated future costs	Range of estimated future costs	$9	-	$36	$5	-	$11	$4	-	$25	Range of estimated future costs	$8	-	-	$29		$6	-	-	$18		$2	-	-	$11
Current and non-current environmental liabilities	Current and non-current environmental liabilities	$18			$8			$10			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.

NOTE 13(e) MISO Transmission Owner Return on Equity Complaints - A group of stakeholders, including MISO cooperative and municipal utilities, previously filed complaints with the Federal Energy Regulatory Commission (FERC) requesting a reduction to the base return on equity authorized for MISO transmission owners, including ITC Midwest LLC and ATC. In 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity authorized for the MISO transmission owners to 9.88% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In 2020, FERC issued orders in response to various rehearing requests and increased the base return on equity authorized for the MISO transmission owners from 9.88% to 10.02% for November 12, 2013 through February 11, 2015, and subsequent to September 28, 2016. In ~~August~~ 2022, the U.S. Court of Appeals for the District of Columbia ~~Circuit~~ vacated FERC’s prior orders that established the base return on equity authorized for the MISO transmission owners and remanded the cases to FERC for further proceedings, which may result in additional changes to the base return on equity authorized for the MISO transmission owners. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.

NOTE 13(f) Collective Bargaining Agreements - At March 31, 2024, employees covered by collective bargaining agreements represented 53%, 70% and 83% of total employees of Alliant Energy, IPL and WPL, respectively. In August 2024, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expires, representing 18% and 53% of total employees of Alliant Energy and IPL, respectively.


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Table of Contents

NOTE 14. SEGMENTS OF BUSINESS

Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy ATC Holdings, Alliant
Utility Non-Utility, Energy
Electric Gas Other Total Parent and Other Consolidated
(in millions)
Three Months Ended September 30, 2023
Revenues $995 $47 $13 $1,055 $22 $1,077
Operating income (loss) 319 (4) — 315 7 322
Net income (loss) attributable to Alliant Energy common shareowners 277 (18) 259
Three Months Ended September 30, 2022
Revenues $1,039 $62 $11 $1,112 $23 $1,135
Operating income (loss) 304 (3) 1 302 7 309
Net income (loss) attributable to Alliant Energy common shareowners 245 (18) 227


Alliant Energy					ATC Holdings,	Alliant
	Utility				Non-Utility,	Energy
	Electric	Gas	Other	Total	Parent and Other	Consolidated
	(in millions)
Three Months Ended March 31, 2024
Revenues	$791	$205	$13	$1,009	$22	$1,031
Operating income	164	47	5	216	6	222
Net income attributable to Alliant Energy common shareowners				155	3	158
Three Months Ended March 31, 2023
Revenues	$768	$276	$11	$1,055	$22	$1,077
Operating income	163	50	4	217	5	222
Net income attributable to Alliant Energy common shareowners				160	3	163

~~Table~~ of ~~Contents~~


IPL	Electric	Gas	Other	Total
	(in millions)
Three Months Ended March 31, 2024
Revenues	$392	$108	$13	$513
Operating income	57	22	6	85
Net income				63
Three Months Ended March 31, 2023
Revenues	$388	$150	$11	$549
Operating income	66	27	3	96
Net income				72

Alliant Energy ATC Holdings, Alliant
Utility Non-Utility, Energy
Electric Gas Other Total Parent and Other Consolidated
(in millions)
Nine Months Ended September 30, 2023
Revenues $2,562 $400 $38 $3,000 $66 $3,066
Operating income 682 48 12 742 18 760
Net income (loss) attributable to Alliant Energy common shareowners 598 (16) 582
Nine Months Ended September 30, 2022
Revenues $2,624 $418 $35 $3,077 $70 $3,147
Operating income 680 62 4 746 23 769
Net income attributable to Alliant Energy common shareowners 574 5 579

IPL Electric Gas Other Total
(in millions)
Three Months Ended September 30, 2023
Revenues $551 $31 $12 $594
Operating income (loss) 171 (2) 4 173
Net income 170
Three Months Ended September 30, 2022
Revenues $596 $33 $11 $640
Operating income (loss) 174 (3) — 171
Net income 154
Nine Months Ended September 30, 2023
Revenues $1,370 $224 $36 $1,630
Operating income 342 25 12 379
Net income 331
Nine Months Ended September 30, 2022
Revenues $1,438 $224 $34 $1,696
Operating income 353 33 3 389
Net income 327


WPL	WPL	Electric	Gas	Other	Total	WPL	Electric		Gas		Other			Total
		(in millions)
Three Months Ended September 30, 2023
	(in millions)											(in millions)
Three Months Ended March 31, 2024
Revenues
Revenues
Revenues	Revenues	$444	$16	$1	$461	$399		$97		$—			$496
Operating income (loss)	Operating income (loss)	148	(2)	(4)	142	Operating income (loss)	107		25		(1)			131
Net income	Net income				107	Net income									92
Three Months Ended September 30, 2022
Three Months Ended March 31, 2023
Revenues
Revenues
Revenues	Revenues	$443	$29	$—	$472	$380		$126		$—			$506
Operating income	Operating income	130	—	1	131	Operating income	97		23		1			121
Net income	Net income				91	Net income									88
Nine Months Ended September 30, 2023
Revenues		$1,192	$176	$2	$1,370
Operating income		340	23	—	363
Net income					267
Nine Months Ended September 30, 2022
Revenues		$1,186	$194	$1	$1,381
Operating income		327	29	1	357
Net income					247


			26

~~Table~~ of ~~Contents~~

NOTE 15. 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 ~~and nine~~ months ended ~~September 30~~March 31 were as follows (in millions):


		IPL
		IPL
		IPL								WPL
		IPL				WPL
		Three Months		Nine Months		Three Months		Nine Months
		2023	2022	2023	2022	2023	2022	2023	2022
		2024
		2024
		2024
Corporate Services billings
Corporate Services billings
Corporate Services billings	Corporate Services billings	$46	$45	$134	$136	$40	$39	$120	$117
Sales credited	Sales credited	3	11	11	11	23	31	45	62
Sales credited
Sales credited
Purchases billed	Purchases billed	133	119	320	342	5	42	21	103
Purchases billed
Purchases billed


			22

Table of Contents

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

IPL WPL
September 30, 2023 December 31, 2022 September 30, 2023 December 31, 2022
Net payables to Corporate Services $136 $103 $71 $56

IPL

WPL

March 31, 2024

December 31, 2023

March 31, 2024

December 31, 2023

Net payables to Corporate Services

$132

$129

$70

$72

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 ~~and nine~~ months ended ~~September 30~~March 31 were as follows (in millions):


		Three Months		Nine Months
		2024
		2023	2022	2023	2022
		2024

		2024
ATC billings to WPL
ATC billings to WPL
ATC billings to WPL	ATC billings to WPL	$41	$38	$119	$107
WPL billings to ATC	WPL billings to ATC	5	6	16	14
WPL billings to ATC
WPL billings to ATC

WPL owed ATC net amounts of $9$10 million as of ~~September 30, 2023~~March 31, 2024 and $10 million as of December 31, ~~2022.~~2023.

ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

This MDA includes information relating to Alliant Energy, and IPL and WPL (collectively, the Utilities), as well as ATC Holdings, AEF and Corporate Services. Where appropriate, information relating to a specific entity has been segregated and labeled as such. The following discussion and analysis should be read in conjunction with the Financial Statements and the Notes included in this report, as well as the financial statements, notes and MDA included in the ~~2022~~2023 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.


			27

~~Table~~ of ~~Contents~~

~~2023~~2024 HIGHLIGHTS

Key highlights since the filing of the ~~2022~~2023 Form 10-K include the following:

Customer Investments:

•In ~~2021,~~March 2024, IPL filed for advance rate-making principles with the IUB for up to 400 MW of solar generation and 75 MW of battery storage. In April 2023, the IUB approved advance rate-making principles for up to 200 MW of solar generation. The IUB’s order included a cost target of $1,575/kilowatt, including AFUDC and transmission upgrade costs among other costs. In May 2023, IPL requested reconsideration of certain ratemaking principles for the up to 200 MW of solar generation, including the cost target and return on common equity. In June 2023, IPL and the IUB filed a joint motion for remandcompleted construction of the ~~other 200~~Duane Arnold solar facility (50 MW of solar generation and 75 MW of battery storage for further reconsideration by the IUB, which was granted by the court. In June 2023, the IUB granted reconsideration of advance rate-making principles for the 400 MW of solar generation and 75 MW of battery storage. In October 2023, the IUB issued an order approving a modified non-unanimous settlement agreement with the Iowa Office of Consumer Advocate among other stakeholders, for up to 400 MW of solar generation, subject to a cost target of $1,650/kilowatt, including AFUDC and transmission upgrade costs among other costs, and a related return on common equity of no less than 10.25% with the opportunity to request a higher return on common equity in future IPL retail electric rate review filings. Any reasonable and prudent costs incurred in excess of the cost target are eligible for recovery at the return on common equity determined in IPL retail electric rate review filings. The IUB’s order also included a consumer protection plan, which monitors IPL’s achievement of certain aggregate summer capacity factors for the up to 400 MW of solar generation 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. In November 2023, IPL accepted these advance rate-making principles.Linn County, Iowa).

•In ~~October 2023,~~March 2024 and April 2024, FERC and the PSCW, respectively, approved the sales of WPL’s partial ownership interests in West Riverside to WEC Energy Group, Inc. (100 MW) and Madison Gas and Electric Company (25 MW). These sales are currently expected to occur in June 2024.

•In April 2024, WPL received ~~an oral decision~~orders from the PSCW authorizing WPL ~~to construct, own and operate approximately 99 MW of battery storage at the Edgewater Generating Station.~~

•In August 2023, WPL received an order from the PSCW authorizing WPL to construct, own and operate 175 MW of battery storage, with 100 MW and 75 MW at the Grant County and Wood County solar projects, respectively.

•~~In June 2023, WPL filed requests with the PSCW for approval~~ to construct improvements at the 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 by the second quarter of 2024.~~

•In April ~~2023,~~2024, IPL and WPL entered into agreements to transfer a portion of the ~~IUB issued a certificate of public convenience, use~~renewable tax credits generated in 2024 and ~~necessity (GCU Certificate) granting IPL approval to construct, own~~2025 from certain wind, solar and ~~operate up to 150 MW of solar generation and up to 75 MW of~~ battery storage ~~at the Wever project~~facilities to other corporate taxpayers in Lee County, Iowa. In March 2023, the IUB issued a GCU Certificate granting IPL approval to construct, own and operate up to 50 MW of solar generation and up to 25 MW of battery storage at the Creston project in Union County, Iowa. These solar projects are included in the IUB’s October 2023 order approving advance rate-making principlesexchange for ~~up to 400 MW of solar generation.~~cash.

Rate Matters:

•~~In April 2023, WPL filed a retail electric~~Refer to Note 3 for discussion of WPL’s March 2024 filing for judicial review of PSCW orders related to the recovery and ~~gas rate review with~~deferral of the ~~PSCW for the 2024/2025 forward-looking Test Period. The key drivers for the filing include revenue requirement impacts of increasing electric and gas rate base, including investments in~~return on incremental solar generation ~~and battery storage. The filing requested approval for WPL to implement increases in annual rates for its retail electric and gas customers of $111 million and $17 million~~construction costs in 2024 respectively, with any granted rate changes expected to be effective on January 1, 2024. WPL’s filing also requested approval to implement an additional $71 million increase in annual rates for its retail electric customers in 2025, with any granted rate changes expected to be effective on January 1,and 2025. WPL also requested to maintain its current authorized return on common equity of 10% and implement an approximate 56% common equity component of its regulatory capital structure, as well as receive continued recovery of and a return on the remaining net book value of Edgewater Unit 5, which is currently expected to be retired by June 1, 2025. A decision from the PSCW is currently expected by the end of 2023.

Environmental Matters:

•In ~~October 2023, IPL filed a retail electric~~April 2024, the EPA issued the final Section 111(d) rule for certain fossil-fueled EGUs and ~~gas rate review~~repealed the Affordable Clean Energy rule. The final Section 111(d) rule requires states to implement plans to reduce carbon dioxide emissions through various Best System of Emission Reduction measures at affected sources, including retirement, enforceable limits on operational capacity, co-firing with ~~the IUB for the October 2024 through September 2025 forward-looking Test Period. The key drivers for the filing include revenue requirement impacts of increasing electric~~low-GHG fuels, or carbon capture and ~~gas rate base, including investments in solar generation~~storage technology. State plans are subject to EPA approval, and ~~repowering~~must be submitted within 24 months of the ~~existing Franklin County wind farm.~~final rule’s effective date, which has not yet been determined. The ~~filing requested approval for IPL~~final rule’s compliance requirements will be phased in beginning in 2030 and covers fossil-fueled EGUs that utilize steam boilers to ~~implement increases in annual rates for its retail electric~~generate electricity, including IPL’s coal-fired Ottumwa Generating Station, George Neal Generating Station, Prairie Creek Generating Station Unit 3 and ~~gas customers of $160 million~~Louisa Generating Station, and ~~$14 million, respectively, with any granted rate changes~~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 and is not currently expected to be effective on October 1, 2024. IPL’s filing also requested approval to implement an additional $124 million increase in annual rates for its retail electric customers in 2025, with any granted rate changes expected to be effective on October 1, 2025. IPL also requested a return on common equity of 10% and a 52% common equity component of its regulatory capital structure, as well as to receive continued recovery of and a return on the remaining net book value of the Lansingimpact WPL’s coal-fired Columbia Energy Center or Edgewater Generating Station ~~through 2037, which was retired in May 2023. A decision~~given current plans to retire these EGUs prior to this deadline. In addition, the final rule does not impact existing natural gas-fired combustion turbines, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center; however, these EGUs could be subject to future Section 111(d) rules to reduce carbon dioxide emissions from existing combustion turbines. Alliant Energy, IPL and WPL are currently unable to predict with certainty the ~~IUB is currently expected by~~future outcome or impact of these matters, including resolution of ongoing litigation that has been suspended while the ~~third quarter of 2024.~~

•~~In August 2023, the PSCW authorized WPL to collect $117 million in higher rates, plus interest, from~~EPA revised its ~~retail electric customers from October 2023 through December 2025 for fuel-related costs incurred by WPL in 2022 that were higher than fuel-related costs used to determine rates for such period.~~

regulations.


			23			28

Table of Contents

•In April 2024, the EPA issued final revised standards under Section 111(b), which establishes carbon dioxide emissions limits from certain new and reconstructed fossil-fueled EGU combustion turbines that commenced operation after May 23, 2023 with a capacity greater than 25 MW. The final revised standards do not apply to IPL’s Marshalltown Generating Station or WPL’s West Riverside Energy Center, which commenced operation prior to the applicability date of the final revised standards. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these revised standards, including resolution of ongoing litigation that has been suspended while the EPA revised its regulations.

•In April 2024, the EPA issued a final rule that revises discharge limits for specific categories of wastewater from existing coal-fired EGUs. The new limitations will be implemented in each facility’s wastewater discharge permits issued by state agencies and become effective as soon as possible but no later than December 31, 2029. Alliant Energy, IPL and WPL are currently evaluating the final rule and are unable to predict with certainty future compliance impacts.

•In April 2024, the EPA issued revisions to the Coal Combustion Residuals Rule, which significantly 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. Alliant Energy, IPL and WPL are currently evaluating the revised Coal Combustion Residuals Rule and are unable to predict with certainty the future outcome or impact of these updates.

Legislative Matters:

•~~Refer to~~ ~~Note 9~~ ~~for discussion of~~In May 2024, the ~~Iowa corporate income tax rate that will be effective January 1, 2024, pursuant to Iowa tax reform~~Major Economic Growth Attraction program was enacted in ~~2022.~~Iowa, which offers various tax incentives for up to two qualified businesses for c

ertain large-scale projects with capital investments greater than $1 billion constructed on certified sites greater than 250 acres in Iowa.

~~Financings~~The most significant provision of this program for Alliant Energy encourages economic development in IPL’s service territory. Alliant Energy has various development-ready sites throughout Iowa, including the 1,300-acre Big Cedar Industrial Center Mega-site in Cedar Rapids, Iowa, and ~~Common Stock Dividends:~~the 465-acre Prairie View Industrial Center Super Park in Ames, Iowa.

•~~Refer~~In May 2024, legislation was enacted in Iowa related to “~~Results~~the advance rate-making principles for certain investments in Iowa. The most signification provisions of ~~Operations~~”this legislation for ~~discussion~~Alliant Energy would allow IPL to include electric storage and nuclear-fired generation projects in the advance rate-making principles request process prior to making these investments in Iowa, and require IPL to obtain a certificate of ~~expected future issuances of common stock~~public convenience, use and ~~common stock dividends, and expected future issuances and retirements of long-term debt, by~~necessity (GCU Certificate) from the ~~end of 2024.~~IUB in order to construct electric storage projects.

RESULTS OF OPERATIONS

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

Overview
-

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

~~Additionally, the~~ table below includes EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of segment performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance.

~~Financial Results Overview~~ - Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners for the three months ended ~~September 30~~March 31 were as follows (dollars in millions, except per share amounts):


		2024
		2024
		2024
		Income (Loss)
		Income (Loss)
		Income (Loss)
		2023		2022
Utilities and Corporate Services
		Income (Loss)	EPS	Income (Loss)	EPS
Utilities and Corporate Services

Utilities and Corporate Services	Utilities and Corporate Services	$281	$1.11	$249	$0.99
ATC Holdings	ATC Holdings	9	0.03	5	0.02
ATC Holdings
ATC Holdings
Non-utility and Parent
Non-utility and Parent
Non-utility and Parent	Non-utility and Parent	(31)	(0.12)	(27)	(0.11)

Alliant Energy Consolidated	Alliant Energy Consolidated	$259	$1.02	$227	$0.90

Alliant Energy Consolidated

Alliant Energy Consolidated

Alliant Energy’s Utilities and Corporate Services net income increased by $32 million for the three-month period, primarily due to higher revenue requirements and AFUDC from WPL’s capital investments, and lower other operation and maintenance expenses. These items were partially offset by higher interest expense.

~~Alliant Energy’s Non-utility and Parent~~ net income decreased by $4 million for the three-month period, primarily due to lower retail electric and gas sales due to impacts of warmer than normal temperatures during the three months ended March 31, 2024, and higher ~~interest expense.~~financing and depreciation expenses. These items were partially offset by higher revenue requirements from WPL’s capital investments.


			24			29

Table of Contents

For the three and nine months ended September 30, operating income and a reconciliation of utility electric and gas margins to the most directly comparable GAAP measure, operating income, was as follows (in millions):

Alliant Energy IPL WPL
Three Months 2023 2022 2023 2022 2023 2022
Operating income $322 $309 $173 $171 $142 $131
Electric utility revenues $995 $1,039 $551 $596 $444 $443
Electric production fuel and purchased power expenses (231) (274) (99) (140) (132) (134)
Electric transmission service expense (154) (157) (115) (115) (39) (42)
Utility Electric Margin (non-GAAP) 610 608 337 341 273 267
Gas utility revenues 47 62 31 33 16 29
Cost of gas sold expense (12) (26) (12) (14) — (13)
Utility Gas Margin (non-GAAP) 35 36 19 19 16 16
Other utility revenues 13 11 12 11 1 —
Non-utility revenues 22 23 — — — —
Other operation and maintenance expenses (160) (172) (84) (90) (64) (70)
Depreciation and amortization expenses (170) (169) (97) (95) (71) (71)
Taxes other than income taxes expense (28) (28) (14) (15) (13) (11)
Operating income $322 $309 $173 $171 $142 $131

Alliant Energy IPL WPL
Nine Months 2023 2022 2023 2022 2023 2022
Operating income $760 $769 $379 $389 $363 $357
Electric utility revenues $2,562 $2,624 $1,370 $1,438 $1,192 $1,186
Electric production fuel and purchased power expenses (553) (633) (213) (290) (341) (343)
Electric transmission service expense (438) (428) (316) (303) (122) (125)
Utility Electric Margin (non-GAAP) 1,571 1,563 841 845 729 718
Gas utility revenues 400 418 224 224 176 194
Cost of gas sold expense (226) (242) (127) (126) (99) (117)
Utility Gas Margin (non-GAAP) 174 176 97 98 77 77
Other utility revenues 38 35 36 34 2 1
Non-utility revenues 66 70 — — — —
Other operation and maintenance expenses (499) (492) (264) (260) (197) (193)
Depreciation and amortization expenses (503) (501) (288) (285) (208) (211)
Taxes other than income taxes expense (87) (82) (43) (43) (40) (35)
Operating income $760 $769 $379 $389 $363 $357

~~Operating~~Net Income Variances - ~~Variances between periods in operating~~The following items contributed to increased (decreased) net income for the three ~~and nine~~ months ended ~~September 30, 2023~~March 31, 2024 compared to the same ~~periods~~period in ~~2022 were as follows~~2023 (in millions):

Three Months Nine Months
Alliant Energy IPL WPL Alliant Energy IPL WPL
Total higher (lower) utility electric margin variance (Refer to details below) $2 ($4) $6 $8 ($4) $11
Total lower utility gas margin variance (Refer to details below) (1) — — (2) (1) —
Total (higher) lower other operation and maintenance expenses variance (Refer to details below) 12 6 6 (7) (4) (4)
Total (higher) lower depreciation and amortization expenses (Refer to Note 2 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)
(1) (2) — (2) (3) 3
Other 1 2 (1) (6) 2 (4)
$13 $2 $11 ($9) ($10) $6


	Alliant Energy	IPL	WPL
Revenues:
Changes in electric utility (Refer to details below)	$23	$4	$19
Changes in gas utility (Refer to details below)	(71)	(42)	(29)
Changes in other utility	2	2	—

Changes in total revenues	(46)	(36)	(10)
Operating expenses:
Changes in electric production fuel and purchased power (Refer to details below)	(6)	(20)	13
Changes in electric transmission service	(6)	1	(7)
Changes in cost of gas sold (Refer to details below)	67	35	33
Changes in other operation and maintenance (Refer to details below)	14	9	3
Changes in depreciation and amortization (Higher primarily due to WPL’s solar generation placed in service in 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 the first quarter of 2023)	(23)	—	(22)

Changes in total operating expenses	46	25	20
Changes in operating income	—	(11)	10
Other income and deductions:
Changes in interest expense (Higher primarily due to financings completed in 2024 and 2023)	(13)	(5)	(5)
Changes in equity income from unconsolidated investments, net (Refer to Note 5 for details)	(2)	—	—
Changes in AFUDC (Primarily due to changes in levels of CWIP balances related to solar generation and battery storage)	—	7	(7)
Changes in Other	2	1	—
Changes in total other income and deductions	(13)	3	(12)
Changes in income before income taxes	(13)	(8)	(2)
Changes in income taxes (Refer to Note 9 for details)	8	(1)	6


Changes in net income	($5)	($9)	$4


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~~Table~~ of ~~Contents~~

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three ~~and nine~~ months ended ~~September 30~~March 31 were as follows:


Alliant Energy	Alliant Energy	Electric				Gas				Alliant Energy	Electric											Gas
	Revenues														Revenues						MWhs Sold					Revenues						Dths Sold
	2024											2024				2023			2024				2023			2024			2023				2024			2023
		Revenues		MWhs Sold		Revenues		Dths Sold
		2023	2022	2023	2022	2023	2022	2023	2022
Three Months
Retail
Retail
Retail	Retail	$895	$908	6,821	6,788	$37	$50	3,283	3,584	$706			$686				5,989			6,201				$192			$262			20,117				22,310
Sales for resale:	Sales for resale:
Wholesale	Wholesale	59	68	795	774	N/A	N/A	N/A	N/A
Bulk power and other		25	47	1,409	985	N/A	N/A	N/A	N/A
Transportation/Other		16	16	14	16	10	12	29,776	30,982
		$995	$1,039	9,039	8,563	$47	$62	33,059	34,566
Nine Months
Retail		$2,310	$2,327	19,005	19,304	$367	$379	31,897	37,284
Sales for resale:
Wholesale
Wholesale	Wholesale	154	168	2,172	2,172	N/A	N/A	N/A	N/A	47			46				679			698				N/A			N/A			N/A				N/A
Bulk power and other	Bulk power and other	62	83	3,756	2,989	N/A	N/A	N/A	N/A	Bulk power and other	21			23				1,670				1,243			N/A			N/A			N/A				N/A
Transportation/Other	Transportation/Other	36	46	43	46	33	39	88,167	83,241	Transportation/Other	17			13				15				15			13			14			33,908				32,614
	$791											$791				$768			8,353				8,157			$205			$276				54,025			54,924
		$2,562	$2,624	24,976	24,511	$400	$418	120,064	120,525

IPL Electric Gas
Revenues MWhs Sold Revenues Dths Sold
2023 2022 2023 2022 2023 2022 2023 2022
Three Months
Retail $520 $559 3,736 3,736 $25 $25 1,658 1,739
Sales for resale:
Wholesale 21 19 213 208 N/A N/A N/A N/A
Bulk power and other 3 9 332 373 N/A N/A N/A N/A
Transportation/Other 7 9 8 9 6 8 9,999 9,743
$551 $596 4,289 4,326 $31 $33 11,657 11,482
Nine Months
Retail $1,291 $1,358 10,599 10,821 $204 $199 16,065 19,118
Sales for resale:
Wholesale 47 49 578 581 N/A N/A N/A N/A
Bulk power and other 12 4 1,188 1,019 N/A N/A N/A N/A
Transportation/Other 20 27 24 25 20 25 31,588 31,917
$1,370 $1,438 12,389 12,446 $224 $224 47,653 51,035

WPL Electric Gas
Revenues MWhs Sold Revenues Dths Sold
2023 2022 2023 2022 2023 2022 2023 2022
Three Months
Retail $375 $349 3,085 3,052 $12 $25 1,625 1,845
Sales for resale:
Wholesale 38 49 582 566 N/A N/A N/A N/A
Bulk power and other 22 38 1,077 612 N/A N/A N/A N/A
Transportation/Other 9 7 6 7 4 4 19,777 21,239
$444 $443 4,750 4,237 $16 $29 21,402 23,084
Nine Months
Retail $1,019 $969 8,406 8,483 $163 $180 15,832 18,166
Sales for resale:
Wholesale 107 119 1,594 1,591 N/A N/A N/A N/A
Bulk power and other 50 79 2,568 1,970 N/A N/A N/A N/A
Transportation/Other 16 19 19 21 13 14 56,579 51,324
$1,192 $1,186 12,587 12,065 $176 $194 72,411 69,490


IPL	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2024	2023	2024	2023	2024	2023	2024	2023

Retail	$376	$362	3,365	3,544	$101	$141	10,205	11,459
Sales for resale:
Wholesale	13	12	182	187	N/A	N/A	N/A	N/A
Bulk power and other	(3)	7	324	496	N/A	N/A	N/A	N/A
Transportation/Other	6	7	8	8	7	9	11,695	12,035
	$392	$388	3,879	4,235	$108	$150	21,900	23,494


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Table of Contents


WPL	Electric				Gas
	Revenues		MWhs Sold		Revenues		Dths Sold
	2024	2023	2024	2023	2024	2023	2024	2023

Retail	$330	$324	2,624	2,657	$91	$121	9,912	10,851
Sales for resale:
Wholesale	34	34	497	511	N/A	N/A	N/A	N/A
Bulk power and other	24	16	1,346	747	N/A	N/A	N/A	N/A
Transportation/Other	11	6	7	7	6	5	22,213	20,579
	$399	$380	4,474	3,922	$97	$126	32,125	31,430

Sales Trends and Temperatures - Alliant Energy’s retail electric ~~and gas~~ sales volumes ~~increased 1% and~~ decreased ~~8%, respectively,~~3% for the three months ended ~~September 30, 2023~~March 31, 2024 compared to the same period in ~~2022,~~2023, primarily due to changes in ~~temperatures.~~sales volumes to industrial customers due to standby service customers that can use other generation and changes in temperatures, partially offset by an additional day of sales due to leap year in 2024. Alliant Energy’s retail ~~electric and~~ gas sales volumes decreased ~~2% and 14%, respectively,~~10% for the ~~nine~~three months ended ~~September 30, 2023~~March 31, 2024 compared to the same period in ~~2022,~~2023, primarily due to changes in ~~temperatures.~~temperatures, partially offset by an additional day of sales due to leap year in 2024.

Estimated ~~increases (decreases)~~decreases to ~~electric and gas margins~~operating income from the impacts of temperatures for the three ~~and nine~~ months ended ~~September 30~~March 31 were as follows (in millions):


		Electric
		Electric
		Electric												Gas
		Electric Margins						Gas Margins
		Three Months			Nine Months			Three Months			Nine Months
		2023	2022	Change	2023	2022	Change	2023	2022	Change	2023	2022	Change
		2024
		2024
		2024
IPL
IPL
IPL	IPL	$7	$4	$3	$3	$15	($12)	($1)	$—	($1)	($4)	$4	($8)
WPL	WPL	3	—	3	(2)	10	(12)	—	—	—	(4)	2	(6)
WPL
WPL
Total Alliant Energy	Total Alliant Energy	$10	$4	$6	$1	$25	($24)	($1)	$—	($1)	($8)	$6	($14)
Total Alliant Energy
Total Alliant Energy

Electric Sales for Resale - Bulk Power and Other - ~~Electric sales for resale~~Bulk power and other volume changes were ~~largely~~ due to changes in sales in the wholesale energy markets operated by MISO. These changes are impacted by several factors, including the availability and dispatch of Alliant Energy’s EGUs and electricity demand within these wholesale energy markets. Changes in ~~sales for resale~~bulk power and other revenues were largely offset by changes in fuel-related costs, and therefore did not have a significant impact on ~~electric margins.~~operating income.

Gas Transportation/Other -Gas transportation/other sales volume changes were largely due to changes in the gas volumes supplied to Alliant Energy’s natural gas-fired EGUs caused by the availability and dispatch of such EGUs. ~~Changes in these transportation/other revenues did not have a significant impact on gas margins.~~

Electric Utility ~~Electric Margin~~Revenue Variances - The following items contributed to increased (decreased) electric utility ~~electric margins~~revenues for the three ~~and nine~~ months ended ~~September 30, 2023~~March 31, 2024 compared to the same ~~periods~~period in ~~2022 as follows~~2023 (in millions):

Three Months Nine Months
Alliant Energy IPL WPL Alliant Energy IPL WPL
Lower (higher) WPL electric fuel-related costs, net of recoveries ($1) $— ($1) $12 $— $12
Higher (lower) revenues at IPL due to changes in the renewable energy rider (mostly offset by changes in income taxes) (3) (3) — 9 9 —
Estimated changes in sales volumes caused by temperatures 6 3 3 (24) (12) (12)
Other — (4) 4 11 (1) 11
$2 ($4) $6 $8 ($4) $11

~~Utility Gas Margin Variances~~ ~~- The following items contributed to increased (decreased) utility gas margins for the three and nine months ended September 30, 2023 compared to the same periods in 2022 as follows (in millions):~~


	Alliant Energy									Alliant Energy		IPL		WPL

		Three Months			Nine Months
		Alliant Energy	IPL	WPL	Alliant Energy	IPL	WPL

Higher revenue requirements at WPL (a)

Higher revenue requirements at WPL (a)

Higher revenue requirements at WPL (a)									$38		$—		$38
Estimated changes in sales volumes caused by temperatures	Estimated changes in sales volumes caused by temperatures	($1)	($1)	$—	($14)	($8)	($6)	Estimated changes in sales volumes caused by temperatures	(10)		(5)		(5)
Higher revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense)		—	—	—	7	7	—
Higher revenue requirements at WPL (a)		1	—	1	6	—	6
Higher (lower) sales for resale bulk power and other revenues								Higher (lower) sales for resale bulk power and other revenues	(2)		(10)		8
Higher (lower) revenues due to changes in retail electric fuel-related costs (Refer to Electric Production Fuel and Purchased Power Expenses Variances below) (a)								Higher (lower) revenues due to changes in retail electric fuel-related costs (Refer to Electric Production Fuel and Purchased Power Expenses Variances below) (a)	(1)		26		(27)
Other	Other	(1)	1	(1)	(1)	—	—	Other	(2)		(7)		5
		($1)	$—	$—	($2)	($1)	$—
	$23									$23		$4		$19

(a)In December ~~2022,~~2023, the PSCW issued an order authorizing an annual base rate increase of $9$49 million for WPL’s retail ~~gas~~electric customers, covering the ~~2023~~2024 forward-looking Test Period, which reflects ~~changes~~revenue requirement impacts of increasing electric rate base and lower forecasted fuel-related expenses.

Gas Utility Revenue Variances - The following items contributed to increased (decreased) gas utility revenues for the three months ended March 31, 2024 compared to the same period in weighted average cost of capital, updated depreciation rates and modifications to certain regulatory asset and regulatory liability amortizations. These retail gas rate changes were effective on January 1, 2023 ~~and extend through the end of 2023.~~(in millions):


	Alliant Energy	IPL	WPL
Lower revenues due to changes in gas costs (Refer to Cost of Gas Sold Expense Variances below)	($67)	($35)	($33)
Estimated changes in sales volumes caused by temperatures	(5)	(3)	(2)
Higher revenue requirements at WPL (a)	5	—	5

Other	(4)	(4)	1
	($71)	($42)	($29)


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(a)In December 2023, the PSCW issued an order authorizing an annual base rate increase of $13 million for WPL’s retail gas customers, covering the 2024 forward-looking Test Period, which reflects revenue requirement impacts of increasing gas rate base.

Electric Production Fuel and Purchased Power Expenses Variances - The following items contributed to (increased) decreased electric production fuel and purchased power expenses for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):


	Alliant Energy	IPL	WPL
Lower electric production fuel costs (a)	$53	$38	$15
Changes in regulatory recovery of retail electric fuel-related costs	(31)	(38)	7
Higher purchased power expense (b)	(27)	(20)	(7)

Other	(1)	—	(2)
	($6)	($20)	$13

(a)Electric production fuel costs decreased primarily due to lower natural gas prices in the first quarter of 2024 compared to the same period in 2023 and lower natural gas volumes due to lower dispatch of IPL’s natural gas-fired EGUs in 2024, partially offset by higher coal volumes due to higher dispatch of WPL’s coal-fired EGUs in 2024.

(b)Purchased power expense increased primarily due to higher prices for electricity purchased by IPL and WPL.

Cost of Gas Sold Expense Variances - The following items contributed to (increased) decreased cost of gas sold expense for the three months ended March 31, 2024 compared to the same period in 2023 (in millions):


	Alliant Energy	IPL	WPL
Lower natural gas prices and lower retail gas volumes primarily due to changes in temperatures	$75	$50	$25
Changes in the regulatory recovery of gas costs	(6)	(14)	8

Other	(2)	(1)	—
	$67	$35	$33

Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three ~~and nine~~ months ended ~~September 30, 2023~~March 31, 2024 compared to the same ~~periods~~period in ~~2022 as follows~~2023 (in millions):

Three Months Nine Months
Alliant Energy IPL WPL Alliant Energy IPL WPL
Higher energy efficiency expense at IPL (mostly offset by higher revenues) ($1) ($1) $— ($10) ($10) $—
Lower (higher) generation and energy delivery expenses 3 1 2 (8) — (8)
Other 10 6 4 11 6 4
$12 $6 $6 ($7) ($4) ($4)

~~Other Income and Deductions Variances~~ - The following items contributed to (increased) decreased other income and deductions for the three and nine months ended September 30, 2023 compared to the same periods in 2022 as follows (in millions):

Three Months Nine Months
Alliant Energy IPL WPL Alliant Energy IPL WPL
Higher interest expense primarily due to financings completed in 2023 and 2022, and higher interest rates ($16) ($1) ($7) ($54) ($2) ($24)
Higher AFUDC primarily due to changes in construction work in progress balances related to WPL’s solar generation 18 3 15 37 5 32
Other 8 (3) 2 6 (5) 3
$10 ($1) $10 ($11) ($2) $11

~~Income Taxes~~ ~~- Refer to~~ ~~Note~~ 9 ~~for details of effective income tax rates.~~

~~Other Future Considerations~~ ~~- In addition to items discussed in this report, the following key items could impact Alliant Energy’s, IPL’s and WPL’s future financial condition or results of operations:~~

• ~~Financing Plans~~ - Alliant Energy currently expects to issue up to $225 million of common stock in 2024 through one or more offerings and its Shareowner Direct Plan. The amount of common stock issued in 2024 will largely be used to fund capital contributions from Alliant Energy to WPL, which is dependent on the PSCW's decision on WPL's common equity component of its capital structure for the 2024/2025 forward-looking Test Period. IPL and AEF currently expect to issue up to $700 million and $1.0 billion of long-term debt, respectively, by the end of 2024. IPL and AEF have $500 million and $400 million of long-term debt, respectively, and AEF has $50 million of short-term borrowings, maturing in 2024.

• ~~Common Stock Dividends~~ - Alliant Energy announced a 6% increase in its expected targeted 2024 annual common stock dividend to $1.92 per share, which is equivalent to a quarterly rate of $0.48 per share, beginning with the February 2024 dividend payment. The timing and amount of future dividends is subject to approved quarterly dividend declarations from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

• ~~Cash Flows From Operating Activities -~~ Alliant Energy, IPL and WPL currently expect an increase in future cash flows from operating activities resulting from the transfer of future renewable tax credits to other corporate taxpayers pursuant to the Inflation Reduction Act of 2022.

• ~~Higher Earnings on Increasing Rate Base~~ ~~- Alliant Energy, IPL and WPL currently expect an increase in earnings in 2024 compared to 2023 due to impacts from increasing revenue requirements related to investments in the utility business.~~

• ~~Depreciation and Amortization Expense~~ - Alliant Energy, IPL and WPL currently expect an increase in depreciation and amortization expense in 2024 compared to 2023 due to capital projects placed in service in 2023 and 2024 and lower amortization of WPL’s West Riverside liquidated damages. Refer to ~~Note 2~~ ~~for discussion of WPL’s West Riverside liquidated damages.~~

• ~~Interest Expense~~ - Alliant Energy, IPL and WPL currently expect an increase in interest expense in 2024 compared to 2023 due to financings completed in 2023 and planned by the end of 2024 as discussed above, as well as expected higher interest rates.

• ~~AFUDC~~ - Alliant Energy and WPL currently expect a decrease and IPL currently expects an increase in AFUDC in 2024 compared to 2023 largely due to changes in construction work in progress balances related to construction activity on capital projects.



	Alliant Energy	IPL	WPL

Lower generation and energy delivery expenses	$8	$1	$7
Lower energy efficiency expense at IPL (mostly offset by higher revenues)	7	7	—

Other	(1)	1	(4)
	$14	$9	$3

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources summary included in the ~~2022~~2023 Form 10-K has not changed materially, except as described below.


			33

~~Table~~ of ~~Contents~~

Liquidity Position - At ~~September 30, 2023,~~March 31, 2024, Alliant Energy had ~~$206~~$32 million of cash and cash equivalents, ~~$549~~$666 million ($~~119~~166 million at the parent company, ~~$250~~$200 million at IPL and ~~$180~~$300 million at WPL) of available capacity under the single revolving credit facility and ~~$109~~$92 million of available capacity at IPL under its sales of accounts receivable program.

Capital Structure - Capital structures at ~~September 30, 2023~~March 31, 2024 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE)):


			27

Table of Contents

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


		Alliant Energy		IPL		WPL
		2023	2022	2023	2022	2023	2022
	Alliant Energy											Alliant Energy				IPL				WPL
	2024									2024			2023		2024			2023		2024		2023
Cash, cash equivalents and restricted cash, January 1	Cash, cash equivalents and restricted cash, January 1	$24	$40	$15	$34	$5	$2	Cash, cash equivalents and restricted cash, January 1	$63		$24			$53			$15		$7		$5
Cash flows from (used for):	Cash flows from (used for):
Operating activities	Operating activities	622	485	191	166	437	279
Operating activities
Operating activities									307		188			76			24		241		185
Investing activities	Investing activities	(952)	(599)	(177)	84	(680)	(612)	Investing activities	(353)		(263)			(107)			70		(213)		(295)
Financing activities	Financing activities	515	421	159	(239)	254	630	Financing activities	18		212			(10)			(74)		(24)		191
Net increase		185	307	173	11	11	297
Cash, cash equivalents and restricted cash, September 30		$209	$347	$188	$45	$16	$299
Net increase (decrease)								Net increase (decrease)	(28)		137			(41)			20		4		81
Cash, cash equivalents and restricted cash, March 31								Cash, cash equivalents and restricted cash, March 31	$35		$161			$12			$35		$11		$86

Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the ~~nine~~three months ended ~~September 30, 2023~~March 31, 2024 compared to the same period in ~~2022~~2023 (in millions):


		Alliant Energy	IPL	WPL

Timing of WPL’s fuel-related cost recoveries from retail electric customers		$137	$—	$137
Changes in levels of gas stored underground and prepaid gas costs		97	46	51

	Alliant Energy						Alliant Energy		IPL		WPL
Higher collections from WPL’s retail electric and gas base rate increases					Higher collections from WPL’s retail electric and gas base rate increases	$43		$—		$43
Changes in the sales of accounts receivable at IPL	Changes in the sales of accounts receivable at IPL	36	36	—	Changes in the sales of accounts receivable at IPL	18		18		—

Changes in interest payments		(60)	4	(28)

Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales	Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales	(38)	(20)	(18)

Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales

Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales						(15)		(8)		(7)

Other (primarily due to other changes in working capital)	Other (primarily due to other changes in working capital)	(35)	(41)	16
		$137	$25	$158
Other (primarily due to other changes in working capital)
Other (primarily due to other changes in working capital)						73		42		20
	$119						$119		$52		$56

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the ~~nine~~three months ended ~~September 30, 2023~~March 31, 2024 compared to the same period in ~~2022~~2023 (in millions):

Alliant Energy IPL WPL
Higher utility construction and acquisition expenditures (a) ($328) ($158) ($170)
Changes in the amount of cash receipts on sold receivables (52) (52) —
Higher non-utility construction and acquisition expenditures (23) — —
Proceeds from sales of partial ownership interest in West Riverside in 2023 120 — 120
Other (70) (51) (18)
($353) ($261) ($68)


	Alliant Energy	IPL	WPL
(Higher) lower utility construction and acquisition expenditures (a)	($61)	($152)	$91
Proceeds from sale of partial ownership interest in West Riverside in 2023	(25)	—	(25)
Changes in the amount of cash receipts on sold receivables	(18)	(18)	—

Other	14	(7)	16
	($90)	($177)	$82

(a)Largely due to higher expenditures for ~~IPL~~IPL’s solar generation and WPL’s battery storage, partially offset by lower expenditures for WPL’s solar generation.


			34

~~Table~~ of ~~Contents~~

~~Construction and Acquisition Expenditures~~ - Construction and acquisition expenditures and financing plans are reviewed, approved and updated as part of the strategic planning process. Changes may result from a number of reasons, including regulatory requirements, changing legislation, not obtaining favorable and acceptable regulatory approval on certain projects, improvements in technology, and improvements to ensure resiliency and reliability of the electric and gas distribution systems. Construction and acquisition expenditures for 2023 through 2027 are currently anticipated as follows (in millions), which are focused on the transition to cleaner energy and strengthening the resiliency and reliability of IPL’s and WPL’s electric grid, and include renewables and battery storage projects, dispatchable gas generation projects and wind repowering projects. Cost estimates represent Alliant Energy’s, IPL’s and WPL’s portion of construction expenditures and exclude AFUDC and capitalized interest, if applicable.

Alliant Energy IPL WPL
2023 2024 2025 2026 2027 2023 2024 2025 2026 2027 2023 2024 2025 2026 2027
Generation:
Renewables and battery storage projects $790 $1,140 $665 $780 $775 $350 $575 $275 $445 $205 $440 $565 $390 $335 $570
Gas projects 40 120 325 610 500 10 55 135 310 125 30 15 125 295 375
Other 95 100 80 50 40 55 55 40 20 15 40 45 40 30 25
Distribution:
Electric systems 565 610 620 670 685 305 355 365 380 395 260 255 255 290 290
Gas systems 80 85 85 85 85 35 40 40 40 40 45 45 45 45 45
Other 220 220 205 240 280 50 45 50 50 45 35 40 30 25 30
$1,790 $2,275 $1,980 $2,435 $2,365 $805 $1,125 $905 $1,245 $825 $850 $965 $885 $1,020 $1,335

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the ~~nine~~three months ended ~~September 30, 2023~~March 31, 2024 compared to the same period in ~~2022~~2023 (in millions):

Alliant Energy IPL WPL
Higher net proceeds from common stock issuances $182 $— $—
Distributions to noncontrolling interest in 2022 29 — 29
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy — 60 (175)
Higher (lower) net proceeds from issuance of long-term debt (80) 296 (291)
Capital contributions from noncontrolling interest in 2022 (29) — (29)
Higher payments to retire long-term debt (25) — —
(Higher) lower common stock dividends (19) 30 (5)
Net changes in the amount of commercial paper and other short-term borrowings outstanding (9) — 66
Other 45 12 29
$94 $398 ($376)

~~State Regulatory Financing Authorization~~ - In March 2023, WPL received authorization from the PSCW to have up to $500 million of short-term borrowings and/or letters of credit outstanding at any time through the expiration date of WPL’s credit facility agreement.


	Alliant Energy	IPL	WPL


Higher payments to retire long-term debt	($300)	$—	$—
Lower net proceeds from issuance of long-term debt	(265)	—	—
(Higher) lower common stock dividends	(10)	20	(3)
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy	—	50	(125)

Net changes in the amount of commercial paper and other short-term borrowings outstanding	391	—	(88)
Other	(10)	(6)	1
	($194)	$64	($215)

Common Stock Issuances ~~and Common Stock Dividends~~ - Refer to Note 6 for discussion of common stock issuances by Alliant Energy in ~~2023. Refer to “Results of Operations” for discussion of expected issuances of common stock and common stock dividends in~~ 2024.

~~Short-term Debt~~ ~~- Refer to~~ N ~~ote 7(a)~~ for discussion of Alliant Energy’s, IPL’s and WPL’s single credit facility agreement that was amended and extended in March 2023, which includes a revised cross-default provision related to prepayment of material debt prior to the stated maturity and certain other confirming changes, as well as details for proceeds from AEF’s December 2022 term loan credit agreement.

Long-term Debt - Refer to Note 7 (b) for discussion of various issuances ~~and~~and/or retirements of long-term debt by ~~Alliant Energy,~~ AEF ~~IPL~~ and WPL in ~~2023. Refer to “Results of Operations” for discussion of expected future issuances and retirements of long-term debt by the end of~~ 2024.

~~Interest Rate Risk~~Impact of Credit Ratings on Liquidity and Collateral Obligations - ~~As of September 30, 2023,~~

Ratings Triggers - In March 2024, Standard & Poor’s Ratings Services changed Alliant Energy’s exposure to risk resulting from changes in interest rates associated with variable-rate borrowings was mitigated primarily due to its issuance of convertible senior notes and an interest rate swap on a portion of its variable-rate term loan borrowings, as well as WPL’s issuance of green bonds and IPL’s ~~issuance of senior debentures, all of which were executed in 2023. Assuming the~~outlooks from stable to negative. These outlook changes are not expected to have a material impact ~~of a hypothetical 100 basis point increase in interest rates~~ on ~~variable-rate borrowings and cash amounts outstanding under IPL’s sales of accounts receivable program at September 30, 2023,~~ Alliant Energy’s ~~annual pre-tax expense would increase by approximately $6 million.~~and IPL’s liquidity or collateral obligations.


			35

~~Table~~ of ~~Contents~~

Off-Balance Sheet Arrangements and Certain Financial Commitments - A summary of Alliant Energy’s and IPL’s off-balance sheet arrangements and Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the ~~2022~~2023 Form 10-K and has not changed materially from the items reported in the ~~2022~~2023 Form 10-K, except for the items described in Notes 4, 7 and 1 3.


			28

Table of Contents

OTHER MATTERS

Critical Accounting ~~Policies and~~ Estimates - The summary of critical accounting ~~policies and~~ estimates included in the ~~2022~~2023 Form 10-K has not changed materially, except as described below.

Long-Lived Assets -

Regulated Operations -

~~Generating Units Subject to Early Retirement~~ Solar Generation Projects Recently Completed or Under Construction- ~~In May 2023, IPL retired the Lansing Generating Station. IPL is currently allowed a full recovery of and a full return on this EGU from both its retail and wholesale customers, and as a result,~~ Alliant Energy and ~~IPL concluded that no impairment was required as of September 30, 2023. Refer to~~ ~~Note 2~~ ~~for further discussion of the Lansing retirement.~~

~~IPL’s Solar Generation Projects Under Construction~~ ~~- As discussed in “2023 Highlights~~,” IPL accepted the IUB’s advance rate-making principles approved in October 2023 for 400 MW of solar generation. Alliant Energy and IPL review property, plant and equipment for possible impairment whenever events or changes in circumstances indicate all or a portion of the carrying value of the assets may be disallowed for rate-making purposes. If IPL is disallowed recovery of any portion of, or is only allowed a partial return on, the carrying value of the solar generation projects under construction, then an impairment charge is recognized. IPLWPL currently ~~expects estimated~~expect construction costs associated with ~~the 400~~WPL’s approximately 1,100 MW of new solar generation will exceed the construction cost ~~target~~estimates previously approved by the ~~IUB~~PSCW by approximately ~~10%.~~$180 million. In February 2024, the PSCW issued an order approving deferral of the incremental solar generation construction costs. The PSCW’s order did not authorize a deferral for the return on such costs. In March 2024, WPL filed for judicial review of the PSCW’s retail electric rate review order (2024/2025 forward-looking Test Period) and solar generation construction cost deferral order related to the recovery and deferral of the return on the incremental solar generation construction costs in 2024 and 2025. Alliant Energy and ~~IPL~~WPL concluded that there was not a probable disallowance of anticipated higher rate base amounts as of ~~September 30, 2023~~March 31, 2024 given construction costs were reasonably and prudently incurred.

~~Environmental Matters~~ - ~~The summary of environmental matters included in the 2022~~ ~~Form 10-K~~ ~~has not changed materially, except as described below.~~

~~Environmental Regulation -~~

~~Clean Air Act (CAA) Section 111(d)~~ - In May 2023, the EPA published proposed standards under Section 111(d) of the CAA, which establish emission guidelines for states to implement Best System of Emission Reduction standards for greenhouse gases emissions from existing fossil-fueled EGUs and certain combustion turbines, and would be phased in beginning in 2030. The EPA also proposed to repeal the Affordable Clean Energy rule. The EPA’s proposed standards would require states to implement plans to reduce carbon dioxide emissions from existing fossil-fueled EGUs and certain combustion turbines through various measures, including retirement, enforceable limits on operational capacity, co-firing with low-greenhouse gases fuels, or other technological controls. State plans must be submitted within 24 months of the final rule’s effective date and are subject to EPA approval. 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. In addition, the proposed standards could impact natural gas-fired combustion turbines with a capacity of 300 MW or more, including IPL’s Marshalltown Generating Station and Emery Generating Station, and WPL’s Riverside Energy Center and West Riverside Energy Center. 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 timeline for expected issuance of the EPA’s final reconsidered 111(d) rule cannot be predicted with certainty, but is expected to be issued in 2024. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these matters.

~~Clean Air Act Section 111(b)~~ - In May 2023, the EPA published proposed standards under Section 111(b) of the CAA, which establish carbon dioxide emissions limits from certain new and reconstructed fossil-fueled EGUs and would apply prospectively. The timeline for expected issuance of the EPA’s final reconsidered 111(b) rule cannot be predicted with certainty, but is expected to be issued in 2024. Marshalltown and West Riverside are currently subject to the EPA’s Section 111(b) regulation. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these standards.

~~Coal Combustion Residuals (CCR) Rule~~ - In May 2023, the EPA published proposed amendments to the CCR Rule, which regulates CCR as a non-hazardous waste. These proposed amendments 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. Alliant Energy, IPL and WPL are currently unable to predict with certainty the future outcome or impact of these updates.

~~Environmental Stewardship -~~ ~~Alliant Energy’s current voluntary environmental-related goals include the following:~~

•By 2030, reduce greenhouse gases emissions from its utility operations by 50% from 2005 levels, reduce its electric utility water supply by 75% from 2005 levels and electrify 100% of its owned light-duty fleet vehicles.

•~~By 2040, eliminate all coal-fired EGUs from its generating fleet and reduce greenhouse gases emissions from its utility operations by 80% from 2005 levels.~~


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~~Table~~ of ~~Contents~~

•~~By 2050, aspire to achieve net-zero greenhouse gases emissions from its utility operations.~~

Alliant Energy’s aspirational greenhouse gases goal includes EPA reportable emissions based on applicable regulatory compliance requirements for carbon dioxide, methane and nitrous oxide from its owned fossil-fueled EGUs and distribution of natural gas. In addition, Alliant Energy’s environmental stewardship efforts include a goal to partner to plant more than 1 million trees by the end of 2030. Future updates to sustainable energy plans and attaining these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Quantitative and Qualitative Disclosures About Market Risk are reported in the ~~2022~~2023 Form 10-K and have not changed materially.

ITEM 4. CONTROLS AND PROCEDURES

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 defined in Rule 13a-15(e) of the Securities Exchange Act of 1934, as amended) as of ~~September 30, 2023~~March 31, 2024 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive ~~Officers~~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 quarter ended ~~September 30, 2023.~~March 31, 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 ~~September 30, 2023~~March 31, 2024 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s or WPL’s internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

None. SEC regulations require Alliant Energy, IPL and WPL to disclose information about certain proceedings arising under federal, state or local environmental provisions when a governmental authority is a party to the proceedings and such proceedings involve potential monetary sanctions that Alliant Energy, IPL and WPL reasonably believe will exceed a specified threshold. Pursuant to the SEC regulations, Alliant Energy, IPL and WPL use a threshold of $1 million for purposes of determining whether disclosure of any such proceedings is required. Applying this threshold, there are no environmental matters to disclose for this period.

ITEM 1A. RISK FACTORS

The risk factors described in Item 1A in the ~~2022~~2023 Form 10-K have not changed materially.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS ~~AND ISSUER PURCHASES OF EQUITY SECURITIES~~

A summary of Alliant Energy common stock repurchases for the quarter ended ~~September 30, 2023~~March 31, 2024 was as follows:

Total Number Average Price Total Number of Shares Maximum Number (or Approximate
of Shares Paid Per Purchased as Part of Dollar Value) of Shares That May
Period Purchased (a) Share Publicly Announced Plan Yet Be Purchased Under the Plan (a)
July 1 through July 31 6,298 $52.95 — N/A
August 1 through August 31 3,724 50.31 — N/A
September 1 through September 30 38 49.97 — N/A
10,060 51.97 —

Total Number

Average Price

Total Number of Shares

Maximum Number (or Approximate

of Shares

Paid Per

Purchased as Part of

Dollar Value) of Shares That May

Period

Purchased (a)

Publicly Announced Plan

Yet Be Purchased Under the Plan (a)

January 1 through January 31

6,936

$50.38

—

N/A

February 1 through February 29

3,393

48.40

—

N/A

March 1 through March 31

439

47.87

—

N/A

10,768

49.65

—


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Table of Contents

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

ITEM 5. OTHER INFORMATION

(c)During the quarter ended ~~September 30, 2023,~~March 31, 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.


			37

~~Table~~ of ~~Contents~~

ITEM 6. EXHIBITS

The following Exhibits are filed herewith or incorporated herein by reference.


Exhibit Number			Description
4.1			~~Officer’s~~Officers’ Certificate, dated as of ~~September~~ 21 ~~, 2023,~~March 7, 2024, creating ~~IPL’s~~ ~~5.7~~0 ~~% Senior~~WPL’s 5.375% Debentures due ~~October 15, 20~~33 March 30, 2034 (incorporated by reference to Exhibit 4.1 to ~~IPL’s~~WPL’s Form 8-K, filed ~~September~~ 21 ~~, 2023~~March 7, 2024 (File No. ~~1-4117)~~0-337))
10.1			Amended and Restated Term Loan Credit Agreement, dated as of March 1, 2024, among AEF, Alliant Energy, U.S. Bank N ational A ssociation and the lender parties set forth therein (incorporated by reference to Exhibit 10.1 to Alliant Energy’s Form 8-K, filed March 5, 2024 (File No. 1-9894))
31.1			Certification of the Chief Executive Officer for Alliant Energy
31.2			Certification of the Chief Financial Officer for Alliant Energy
31.3			Certification of the Chief Executive Officer for IPL
31.4			Certification of the Chief Financial Officer for IPL
31.5			Certification of the Chief Executive Officer for WPL
31.6			Certification of the Chief Financial Officer for WPL
32.1			Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for Alliant Energy
32.2			Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for IPL
32.3			Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for WPL
101.INS			Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document
101.SCH			Inline XBRL Taxonomy Extension Schema Document
101.CAL			Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.LAB			Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE			Inline XBRL Taxonomy Extension Presentation Linkbase Document
101.DEF			Inline XBRL Taxonomy Extension Definition Linkbase Document
104			Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company have each duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized on the 3rd day of ~~November 2023.~~May 2024.


ALLIANT ENERGY CORPORATION
Registrant

By: /s/ Benjamin M. Bilitz			Chief Accounting Officer and Controller
Benjamin M. Bilitz			(Principal Accounting Officer and Authorized Signatory)


INTERSTATE POWER AND LIGHT COMPANY
Registrant

By: /s/ Benjamin M. Bilitz			Chief Accounting Officer and Controller
Benjamin M. Bilitz			(Principal Accounting Officer and Authorized Signatory)


WISCONSIN POWER AND LIGHT COMPANY
Registrant

By: /s/ Benjamin M. Bilitz			Chief Accounting Officer and Controller
Benjamin M. Bilitz			(Principal Accounting Officer and Authorized Signatory)


			30			38


	Originated in 2022		Originated in 2023
	Three Months	Nine Months	Three Months	Nine Months
Alliant Energy	$3	$11	$6	$8
IPL	2	7	4	5
WPL	1	4	2	3


Alliant Energy	Total Alliant Energy Common Equity
				Accumulated	Shares in
		Additional		Other	Deferred
	Common	Paid-In	Retained	Comprehensive	Compensation	Noncontrolling	Total
	Stock	Capital	Earnings	Income	Trust	Interest	Equity
Three Months Ended September 30, 2023
Beginning balance, June 30, 2023	$3	$2,854	$3,606	$3	($14)	$—	$6,452
Net income attributable to Alliant Energy common shareowners			259				259
Common stock dividends ($0.4525 per share)			(115)				(115)
At-the-market offering program and Shareowner Direct Plan issuances		125					125
Equity-based compensation plans and other		3			1		4



Other comprehensive income, net of tax				1			1
Ending balance, September 30, 2023	$3	$2,982	$3,750	$4	($13)	$—	$6,726
Three Months Ended September 30, 2022
Beginning balance, June 30, 2022	$3	$2,759	$3,387	$—	($12)	$29	$6,166
Net income attributable to Alliant Energy common shareowners			227				227
Common stock dividends ($0.4275 per share)			(106)				(106)
Shareowner Direct Plan issuances		6					6
Equity-based compensation plans and other		2			(1)		1

Distributions to noncontrolling interest						(29)	(29)


Ending balance, September 30, 2022	$3	$2,767	$3,508	$—	($13)	$—	$6,265


WPL	Total WPL Common Equity
		Additional
	Common	Paid-In	Retained	Noncontrolling	Total
	Stock	Capital	Earnings	Interest	Equity
Three Months Ended September 30, 2023
Beginning balance, June 30, 2023	$66	$2,413	$1,260	$—	$3,739
Net income			107		107
Common stock dividends			(46)		(46)
Capital contributions from parent		65			65



Ending balance, September 30, 2023	$66	$2,478	$1,321	$—	$3,865
Three Months Ended September 30, 2022
Beginning balance, June 30, 2022	$66	$1,968	$1,120	$29	$3,183
Net income			91		91
Common stock dividends			(44)		(44)
Capital contributions from parent		155			155

Distributions to noncontrolling interest				(29)	(29)

Ending balance, September 30, 2022	$66	$2,123	$1,167	$—	$3,356



	Alliant Energy		IPL		WPL
Nine Months Ended September 30	2023	2022	2023	2022	2023	2022
Electric Utility:
Retail - residential	$943	$956	$503	$529	$440	$427
Retail - commercial	627	628	399	411	228	217
Retail - industrial	740	743	389	418	351	325
Wholesale	154	168	47	49	107	119
Bulk power and other	98	129	32	31	66	98
Total Electric Utility	2,562	2,624	1,370	1,438	1,192	1,186
Gas Utility:
Retail - residential	233	237	131	127	102	110
Retail - commercial	122	127	65	62	57	65
Retail - industrial	12	15	8	10	4	5
Transportation/other	33	39	20	25	13	14
Total Gas Utility	400	418	224	224	176	194
Other Utility:
Steam	32	29	32	29	—	—
Other utility	6	6	4	5	2	1
Total Other Utility	38	35	36	34	2	1
Non-Utility and Other:
Travero and other	66	70	—	—	—	—

Total Non-Utility and Other	66	70	—	—	—	—
Total revenues	$3,066	$3,147	$1,630	$1,696	$1,370	$1,381


	Alliant Energy	IPL	WPL
Higher utility construction and acquisition expenditures (a)	($328)	($158)	($170)
Changes in the amount of cash receipts on sold receivables	(52)	(52)	—
Higher non-utility construction and acquisition expenditures	(23)	—	—
Proceeds from sales of partial ownership interest in West Riverside in 2023	120	—	120
Other	(70)	(51)	(18)
	($353)	($261)	($68)


	Alliant Energy	IPL	WPL
Higher net proceeds from common stock issuances	$182	$—	$—
Distributions to noncontrolling interest in 2022	29	—	29
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy	—	60	(175)
Higher (lower) net proceeds from issuance of long-term debt	(80)	296	(291)
Capital contributions from noncontrolling interest in 2022	(29)	—	(29)
Higher payments to retire long-term debt	(25)	—	—
(Higher) lower common stock dividends	(19)	30	(5)
Net changes in the amount of commercial paper and other short-term borrowings outstanding	(9)	—	66
Other	45	12	29
	$94	$398	($376)