UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

FORM 10-Q

(Mark One)

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

For the quarterly period ended March 31, 2025

or

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

For the transition period from to

Commission File Number: 001-03140

Northern States Power Company

(Exact Name of Registrant as Specified in its Charter)

Wisconsin			39-0508315
(State or Other Jurisdiction of Incorporation or Organization)			(I.R.S Employer Identification No.)
1414 West Hamilton Avenue	Eau Claire	Wisconsin	54701
(Address of Principal Executive Offices)			(Zip Code)

(715)	852-5812
(Registrant’s Telephone Number, Including Area Code)

N/A

(Former name, former address and former fiscal year, if changed since last report)

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

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
N/A	N/A	N/A

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. ☒ 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). ☒ 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.

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. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). ☐ Yes ☒ No

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

Class	Outstanding at April 24, 2025
Common Stock, $100 par value	933,000 shares

Northern States Power Company meets the conditions set forth in General Instructions H(1)(a) and (b) of Form 10-Q and is therefore filing this Form 10-Q with the reduced disclosure format specified in General Instruction H(2) to such Form 10-Q.

TABLE OF CONTENTS

PART I	FINANCIAL INFORMATION
Item 1 —	Financial Statements (unaudited)	4
	Consolidated Statements of Income	4
	Consolidated Statements of Cash Flows	5
	Consolidated Balance Sheets	6
	Consolidated Statements of Common Stockholder's Equity	7
	Notes to Consolidated Financial Statements	8
Item 2 —	Management’s Discussion and Analysis of Financial Condition and Results of Operations	11
Item 4 —	Controls and Procedures	14
PART II	OTHER INFORMATION
Item 1 —	Legal Proceedings	14
Item 1A —	Risk Factors	14
Item 5 —	Other Information	15
Item 6 —	Exhibits	15
SIGNATURES		16

This Form 10-Q is filed by NSP-Wisconsin. NSP-Wisconsin is a wholly owned subsidiary of Xcel Energy Inc. Additional information on Xcel Energy is available in various filings with the SEC. This report should be read in its entirety.

Definitions of Abbreviations

Xcel Energy Inc.’s Subsidiaries and Affiliates (current and former)
e prime	e prime inc.
NSP-Minnesota	Northern States Power Company, a Minnesota corporation
NSP System	The electric production and transmission system of NSP-Minnesota and NSP-Wisconsin operated on an integrated basis and managed by NSP-Minnesota
NSP-Wisconsin	Northern States Power Company, a Wisconsin corporation
PSCo	Public Service Company of Colorado
SPS	Southwestern Public Service Company
Utility subsidiaries	NSP-Minnesota, NSP-Wisconsin, PSCo and SPS
Xcel Energy	Xcel Energy Inc. and its subsidiaries

Federal and State Regulatory Agencies
EPA	United States Environmental Protection Agency
FASB	Financial Accounting Standards Board
FERC	Federal Energy Regulatory Commission
MPUC	Minnesota Public Utilities Commission
PSCW	Public Service Commission of Wisconsin
SEC	Securities and Exchange Commission

Other
ASU	Accounting standards update
C&I	Commercial and Industrial
CEO	Chief executive officer
CERCLA	Comprehensive Environmental Response, Compensation, and Liability Act
CFO	Chief financial officer
CO2	Carbon dioxide
ETR	Effective tax rate
GAAP	United States generally accepted accounting principles
MGP	Manufactured gas plant
NOx	Nitrogen Oxides
PFAS	Per- and Polyfluoroalkyl Substances
O&M	Operating and maintenance
RDF	Refuse-derived fuel
RFP	Request for proposal
ROE	Return on equity
Measurements
MW	Megawatts

Forward-Looking Statements

Except for the historical statements contained in this report, the matters discussed herein are forward-looking statements that are subject to certain risks, uncertainties and assumptions. Such forward-looking statements, including those relating to future sales, future expenses, future tax rates, future operating performance, estimated base capital expenditures and financing plans, projected capital additions and forecasted annual revenue requirements with respect to rider filings, expected rate increases or refunds to customers, expectations and intentions regarding regulatory proceedings, expected pension contributions, and expected impact on our results of operations, financial condition and cash flows of legal proceeding outcomes, as well as assumptions and other statements are intended to be identified in this document by the words “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “objective,” “outlook,” “plan,” “project,” “possible,” “potential,” “should,” “will,” “would” and similar expressions. Actual results may vary materially. Forward-looking statements speak only as of the date they are made, and we expressly disclaim any obligation to update any forward-looking information. The following factors, in addition to those discussed in NSP-Wisconsin's Annual Report on Form 10-K for the fiscal year ended Dec. 31, 2024 and subsequent filings with the SEC, could cause actual results to differ materially from management expectations as suggested by such forward-looking information: operational safety; successful long-term operational planning; commodity risks associated with energy markets and production; rising energy prices and fuel costs; qualified employee workforce and third-party contractor factors; violations of our Codes of Conduct; our ability to recover costs; changes in regulation; reductions in our credit ratings and the cost of maintaining certain contractual relationships; general economic conditions, including recessionary conditions, inflation rates, monetary fluctuations, supply chain constraints and their impact on capital expenditures and/or the ability of NSP-Wisconsin to obtain financing on favorable terms; availability or cost of capital; our customers’ and counterparties’ ability to pay their debts to us; assumptions and costs relating to funding our employee benefit plans and health care benefits; tax laws; uncertainty regarding epidemics; effects of geopolitical events, including war and acts of terrorism; cybersecurity threats and data security breaches; seasonal weather patterns; changes in environmental laws and regulations; climate change and other weather events; natural disaster and resource depletion, including compliance with any accompanying legislative and regulatory changes; costs of potential regulatory penalties and wildfire damages in excess of liability insurance coverage; regulatory changes and/or limitations related to the use of natural gas as an energy source; challenging labor market conditions and our ability to attract and retain a qualified workforce; and our ability to execute on our strategies or achieve expectations related to environmental, social and governance matters including as a result of evolving legal, regulatory and other standards, processes, and assumptions, the pace of scientific and technological developments, increased costs, the availability of requisite financing, and changes in carbon markets.

PART I — FINANCIAL INFORMATION

ITEM 1 — FINANCIAL STATEMENTS

NSP-WISCONSIN AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

(amounts in millions)

	Three Months Ended March 31
	2025		2024
Operating revenues
Electric, non-affiliates	$	203	$	203
Electric, affiliates	56		53
Natural gas	68		54
Total operating revenues	327		310
Operating expenses
Electric fuel and purchased power, non-affiliates	4		4
Purchased power, affiliates	102		103
Cost of natural gas sold and transported	33		24
Operating and maintenance expenses	63		56
Conservation program expenses	3		3
Depreciation and amortization	49		45
Taxes (other than income taxes)	8		9
Total operating expenses	262		244
Operating income	65		66
Allowance for funds used during construction — equity	5		3
Interest charges and financing costs
Interest charges and other financing costs	18		14
Allowance for funds used during construction — debt	(2)		(1)
Total interest charges and financing costs	16		13
Income before income taxes	54		56
Income tax expense	12		13
Net income	$	42	$	43

See Notes to Consolidated Financial Statements

4

NSP-WISCONSIN AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

(amounts in millions)

	Three Months Ended March 31
	2025		2024
Operating activities
Net income	$	42	$	43
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	50		46
Deferred income taxes	4		3
Allowance for equity funds used during construction	(5)		(3)
Provision for bad debts	2		1
Changes in operating assets and liabilities:
Accounts receivable	9		(13)
Accrued unbilled revenues	6		9
Inventories	(2)		3
Other current assets	6		5
Accounts payable	4		(7)
Net regulatory assets and liabilities	7		(1)
Other current liabilities	11		5
Pension and other employee benefit obligations	(9)		(7)
Other, net	(1)		2
Net cash provided by operating activities	124		86
Investing activities
Capital/construction expenditures	(120)		(121)
Investments in utility money pool arrangement	(41)		—
Repayments from utility money pool arrangement	56		—
Net cash used in investing activities	(105)		(121)
Financing activities
Repayments of short-term borrowings, net	(35)		(60)
Borrowings under utility money pool arrangement	82		130
Repayments under utility money pool arrangement	(82)		(111)
Capital contributions from parent	33		106
Dividends paid to parent	(13)		(25)
Net cash (used) provided by financing activities	(15)		40
Net change in cash, cash equivalents and restricted cash	4		5
Cash, cash equivalents and restricted cash at beginning of period	8		6
Cash, cash equivalents and restricted cash at end of period	$	12	$	11
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	$	(11)	$	(12)
Cash paid for income taxes, net	(3)		(7)
Supplemental disclosure of non-cash investing and financing transactions:
Accrued property, plant and equipment additions	$	52	$	33
Inventory transfers to property, plant and equipment	4		2
Allowance for equity funds used during construction	5		3

See Notes to Consolidated Financial Statements

5

NSP-WISCONSIN AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS (UNAUDITED)

(amounts in millions, except share and per share data)

	March 31, 2025		Dec. 31, 2024
Assets
Current assets
Cash and cash equivalents	$	12	$	8
Accounts receivable, net	89		72
Investments in money pool arrangements	—		15
Accounts receivable from affiliates	2		33
Accrued unbilled revenues	54		60
Inventories	26		28
Regulatory assets	22		23
Prepaid taxes	22		28
Prepayments and other	13		13
Total current assets	240		280
Property, plant and equipment, net	3,779		3,670
Other assets
Regulatory assets	165		168
Other	8		8
Total other assets	173		176
Total assets	$	4,192	$	4,126
Liabilities and Equity
Current liabilities
Short-term debt	$	—	$	35
Accounts payable	83		72
Accounts payable to affiliates	26		13
Dividends payable to parent	19		13
Regulatory liabilities	36		29
Taxes accrued	17		11
Accrued interest	19		15
Other	25		25
Total current liabilities	225		213
Deferred credits and other liabilities
Deferred income taxes	349		342
Regulatory liabilities	459		456
Customer advances	28		29
Pension and employee benefit obligations	15		24
Other	40		39
Total deferred credits and other liabilities	891		890
Commitments and contingencies
Capitalization
Long-term debt	1,406		1,406
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at March 31, 2025 and Dec. 31, 2024, respectively	93		93
Additional paid in capital	1,076		1,046
Retained earnings	501		478
Total common stockholder's equity	1,670		1,617
Total liabilities and equity	$	4,192	$	4,126

See Notes to Consolidated Financial Statements

6

NSP-WISCONSIN AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY (UNAUDITED)

(amounts in millions, except share data)

	Common Stock Issued					Retained Earnings		Total Common Stockholder's Equity
	Shares	Par Value		Additional Paid In Capital
Three Months Ended March 31, 2025 and 2024
Balance at Dec. 31, 2023	933,000	$	93	$	843	$	430	$	1,366
Net income						43		43
Common dividends declared to parent						(18)		(18)
Contribution of capital by parent				95				95
Balance at March 31, 2024	933,000	$	93	$	938	$	455	$	1,486
Balance at Dec. 31, 2024	933,000	$	93	$	1,046	$	478	$	1,617
Net income						42		42
Common dividends declared to parent						(19)		(19)
Contribution of capital by parent				30				30
Balance at March 31, 2025	933,000	$	93	$	1,076	$	501	$	1,670

See Notes to Consolidated Financial Statements

7

NSP-WISCONSIN AND SUBSIDIARIES

Notes to Consolidated Financial Statements (UNAUDITED)

In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly, in accordance with GAAP, the financial position of NSP-Wisconsin and its subsidiaries as of March 31, 2025 and Dec. 31, 2024; the results of NSP-Wisconsin's operations, including the components of net income, cash flows and changes in stockholder's equity for the three months ended March 31, 2025 and 2024.

All adjustments are of a normal, recurring nature, except as otherwise disclosed. Management has also evaluated the impact of events occurring after March 31, 2025 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation. The Dec. 31, 2024 balance sheet information has been derived from the audited 2024 consolidated financial statements included in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2024.

Notes to the consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC for Quarterly Reports on Form 10-Q. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP on an annual basis have been condensed or omitted pursuant to such rules and regulations. For further information, refer to the consolidated financial statements and notes thereto included in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2024, filed with the SEC on Feb. 27, 2025. Due to the seasonality of NSP-Wisconsin’s electric and natural gas sales, interim results are not necessarily an appropriate base from which to project annual results.

1. Summary of Significant Accounting Policies

The significant accounting policies set forth in Note 1 to the consolidated financial statements in the NSP-Wisconsin Annual Report on Form 10-K for the year ended Dec. 31, 2024 appropriately represent, in all material respects, the current status of accounting policies and are incorporated herein by reference.

2. Accounting Pronouncements

Recently Issued

Income Taxes — In December 2023, the FASB issued ASU 2023-09 – Income Taxes (Topic 740) – Improvements to Income Tax Disclosures, with new disclosure requirements including presentation of prescribed line items in the ETR reconciliation and disclosures regarding state and local tax payments. The ASU is effective for annual periods beginning after Dec. 15, 2024, and NSP-Wisconsin does not expect implementation of the new disclosure guidance to have a material impact on its consolidated financial statements.

Disaggregation of Income Statement Expenses — In November 2024, the FASB issued ASU 2024-03 – Disaggregation of Income Statement Expenses, which requires disclosure of additional detail for certain categories of income statement expenses. The ASU is effective for annual periods beginning after Dec. 15, 2026 and interim reporting periods beginning after Dec. 15, 2027. NSP-Wisconsin is currently evaluating the impact of the new disclosure guidance.

3. Selected Balance Sheet Data

(Millions of dollars)	March 31, 2025		Dec. 31, 2024
Accounts receivable, net
Accounts receivable	$	96	$	79
Less allowance for bad debts	(7)		(7)
Accounts receivable, net	$	89	$	72

(Millions of dollars)	March 31, 2025		Dec. 31, 2024
Inventories
Materials and supplies	$	15	$	13
Fuel	10		10
Natural gas	1		5
Total inventories	$	26	$	28

(Millions of dollars)	March 31, 2025		Dec. 31, 2024
Property, plant and equipment, net
Electric plant	$	4,170	$	4,103
Natural gas plant	555		547
Common and other property	311		309
Construction work in progress	468		406
Total property, plant and equipment	5,504		5,365
Less accumulated depreciation	(1,725)		(1,695)
Property, plant and equipment, net	$	3,779	$	3,670

4. Borrowings and Other Financing Instruments

Short-Term Borrowings

NSP-Wisconsin meets its short-term liquidity requirements primarily through the issuance of commercial paper and borrowings under its credit facility and the money pool.

Money Pool — Xcel Energy Inc. and its utility subsidiaries have established a money pool arrangement that allows for short-term investments in and borrowings between the utility subsidiaries. Xcel Energy Inc. may make investments in the utility subsidiaries at market-based interest rates; however, the money pool arrangement does not allow the utility subsidiaries to make investments in Xcel Energy Inc.

Money pool borrowings:

(Amounts in Millions, Except Interest Rates)	Three Months Ended March 31, 2025			Year Ended Dec. 31, 2024
Borrowing limit	$	150		$	150
Amount outstanding at period end	—			—
Average amount outstanding	3			4
Maximum amount outstanding	30			54
Weighted average interest rate, computed on a daily basis	4.28		%	5.34		%
Weighted average interest rate at period end	N/A			N/A

Commercial Paper — Commercial paper outstanding:

(Amounts in Millions, Except Interest Rates)	Three Months Ended March 31, 2025			Year Ended Dec. 31, 2024
Borrowing limit	$	150		$	150
Amount outstanding at period end	—			35
Average amount outstanding	12			11
Maximum amount outstanding	50			99
Weighted average interest rate, computed on a daily basis	4.57		%	5.42		%
Weighted average interest rate at period end	N/A			4.59

8

Letters of Credit — NSP-Wisconsin uses letters of credit, generally with terms of one year, to provide financial guarantees for certain obligations. At both March 31, 2025 and Dec. 31, 2024, there were immaterial letters of credit outstanding under the credit facility.

Revolving Credit Facility — In order to issue its commercial paper, NSP-Wisconsin must have a revolving credit facility equal to or greater than the commercial paper borrowing limit and cannot issue commercial paper exceeding available capacity under this credit facility. The credit facility provides short-term financing in the form of notes payable to banks, letters of credit and back-up support for commercial paper borrowings.

NSP-Wisconsin has the right to request an extension of the revolving credit facility termination date for an additional one-year period. All extension requests are subject to majority bank group approval.

As of March 31, 2025, NSP-Wisconsin had the following committed revolving credit facility available (in millions of dollars):

Credit Facility (a)		Outstanding (b)		Available
$	150	$	—	$	150

(a)Expires in September 2027.

(b)Includes outstanding commercial paper.

All credit facility bank borrowings, outstanding letters of credit and outstanding commercial paper reduce the available capacity under the credit facility. NSP-Wisconsin had no direct advances on the credit facility outstanding at March 31, 2025 and Dec. 31, 2024.

Other Borrowings — Clearwater Investments, Inc., a NSP-Wisconsin subsidiary, had an immaterial note payable to Xcel Energy Inc. as of March 31, 2025 and Dec. 31, 2024.

5. Revenues

Revenue is classified by the type of goods/services rendered and market/customer type. NSP-Wisconsin’s operating revenues consisted of the following:

	Three Months Ended March 31, 2025
(Millions of Dollars)	Electric		Natural Gas		Total
Major revenue types
Revenue from contracts with customers:
Residential	$	81	$	38	$	119
C&I	114		28		142
Other	2		—		2
Total retail	197		66		263
Interchange and other	59		1		60
Total revenue from contracts with customers	256		67		323
Alternative revenue and other	3		1		4
Total revenues	$	259	$	68	$	327

	Three Months Ended March 31, 2024
(Millions of Dollars)	Electric		Natural Gas		Total
Major revenue types
Revenue from contracts with customers:
Residential	$	77	$	30	$	107
C&I	118		22		140
Other	2		—		2
Total retail	197		52		249
Interchange and other	56		1		57
Total revenue from contracts with customers	253		53		306
Alternative revenue and other	3		1		4
Total revenues	$	256	$	54	$	310

6. Income Taxes

Reconciliation between the statutory rate and effective tax rate:

	Three Months Ended March 31
	2025		2024
Federal statutory rate	21.0	%	21.0	%
State income tax on pretax income, net of federal tax effect	6.2		6.2
Decreases in tax from:
Plant regulatory differences (a)	(4.5)		(4.3)
Other, net	(0.5)		0.3
Effective income tax rate	22.2	%	23.2	%

(a)Plant regulatory differences primarily relate to the credit of excess deferred taxes to customers. Income tax benefits associated with the credit are offset by corresponding revenue reductions.

7. Fair Value of Financial Assets and Liabilities

Fair Value Measurements

Accounting guidance for fair value measurements and disclosures provides a hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value.

•Level 1 — Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. The types of assets and liabilities included in Level 1 are actively traded instruments with observable actual trading prices.

•Level 2 — Pricing inputs are other than actual trading prices in active markets, but are either directly or indirectly observable as of the reporting date. The types of assets and liabilities included in Level 2 are typically either comparable to actively traded securities or contracts or priced with models using highly observable inputs.

•Level 3 — Significant inputs to pricing have little or no observability as of the reporting date. The types of assets and liabilities included in Level 3 include those valued with models requiring significant judgment or estimation.

Fair Value of Long-Term Debt

As of March 31, 2025, other financial instruments for which the carrying amount did not equal fair value:

	March 31, 2025				Dec. 31, 2024
(Millions of Dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term debt, including current portion	$	1,406	$	1,316	$	1,406	$	1,299

9

Fair value of NSP-Wisconsin’s long-term debt is estimated based on recent trades and observable spreads from benchmark interest rates for similar securities. Fair value estimates are based on information available to management as of March 31, 2025 and Dec. 31, 2024, and given the observability of the inputs, fair values presented for long-term debt were assigned as Level 2.

8. Benefit Plans and Other Postretirement Benefits

Components of Net Periodic Benefit Cost

	Three Months Ended March 31
	2025		2024
(Millions of Dollars)	Pension Benefits
Service cost	$	1	$	1
Interest cost (a)	1		2
Expected return on plan assets (a)	(2)		(2)
Net periodic benefit cost	—		1
Net benefit cost recognized for financial reporting	$	—	$	1

(a)The components of net periodic cost other than the service cost component are included in the consolidated statements of income or capitalized on the consolidated balance sheets as a regulatory asset.

In January 2025, contributions totaling $125 million were made across Xcel Energy’s pension plans, of which $9 million was attributable to NSP-Wisconsin. Xcel Energy does not expect additional pension contributions during 2025.

9. Commitments and Contingencies

Legal

NSP-Wisconsin is involved in various litigation matters in the ordinary course of business. The assessment of whether a loss is probable or is a reasonable possibility, and whether the loss or a range of loss is estimable, often involves a series of complex judgments about future events. Management maintains accruals for losses probable of being incurred and subject to reasonable estimation. Management is sometimes unable to estimate an amount or range of a reasonably possible loss in certain situations, including but not limited to when (1) the damages sought are indeterminate, (2) the proceedings are in the early stages, or (3) the matters involve novel or unsettled legal theories.

In such cases, there is considerable uncertainty regarding the timing or ultimate resolution, including a possible eventual loss. For current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, would have a material effect on NSP-Wisconsin’s consolidated financial statements. Legal fees are generally expensed as incurred.

Gas Trading Litigation — e prime is a wholly owned subsidiary of Xcel Energy. e prime was in the business of natural gas trading and marketing but has not engaged in natural gas trading or marketing activities since 2003. Multiple lawsuits involving multiple plaintiffs seeking monetary damages were commenced against e prime and its affiliates, including Xcel Energy, between 2003 and 2009 alleging fraud and anticompetitive activities in conspiring to restrain the trade of natural gas and manipulate natural gas prices. Cases were all consolidated in the U.S. District Court in Nevada.

One case remains active which includes a multi-district litigation matter consisting of a Wisconsin purported class (Arandell Corp.). The Court issued a ruling in June 2022 granting plaintiffs’ class certification. In April 2023, the Seventh Circuit Court of Appeals heard the defendants’ appeal challenging whether the district court properly assessed class certification. A decision relating to class certification is forthcoming. Xcel Energy considers the reasonably possible loss associated with this litigation to be immaterial.

Rate Matters

NSP-Wisconsin is involved in various regulatory proceedings arising in the ordinary course of business. Until resolution, typically in the form of a rate order, uncertainties may exist regarding the ultimate rate treatment for certain activities and transactions. Amounts have been recognized for probable and reasonably estimable losses that may result. Unless otherwise disclosed, any reasonably possible range of loss in excess of any recognized amount is not expected to have a material effect on the financial statements.

Environmental

New and changing federal and state environmental mandates can create financial liabilities for NSP-Wisconsin, which are normally recovered through the regulated rate process.

Site Remediation

Various federal and state environmental laws impose liability where hazardous substances or other regulated materials have been released to the environment. NSP-Wisconsin may sometimes pay all or a portion of the cost to remediate sites where past activities of their predecessors or other parties have caused environmental contamination.

Environmental contingencies could arise from various situations, including sites of former MGPs; and third-party sites, such as landfills, for which NSP-Wisconsin is alleged to have sent wastes to that site.

MGP, Landfill and Disposal Sites

NSP-Wisconsin is investigating, remediating or performing post-closure actions at one MGP, landfill or other disposal site across its service territories.

NSP-Wisconsin has recognized approximately $12 million of remaining liabilities for resolution of these issues, however, the final outcome and timing are unknown. In addition, there may be regulatory recovery, insurance recovery and/or recovery from other potentially responsible parties, offsetting a portion of costs incurred.

Water and Waste

Coal Ash Regulation — NSP-Wisconsin is subject to the CCR Rule, which imposes requirements for handling, storage, treatment and disposal of coal ash and other solid waste.

In May 2024, final amendments to the CCR Rule were published, widening its scope to include legacy CCR surface impoundments at inactive facilities and previously exempt areas where CCR was placed directly on land at CCR-regulated facilities, including areas of beneficial use.

As a requirement of the CCR Rule, utilities must complete facility evaluations and groundwater sampling around their subject landfills, surface impoundments and certain other areas where coal ash was placed on land.

10

If certain impacts to groundwater are detected, utilities are required to perform additional groundwater investigations and/or perform corrective actions, beginning with an Assessment of Corrective Measures.

NSP-Wisconsin expects to incur nominal expenses for investigations through 2028 to perform required reporting and assess whether corrective actions are necessary. AROs have been recorded for each of these activities, and amounts are expected to be recoverable through regulatory mechanisms.

NSP-Wisconsin continues to perform site investigation activities related to the CCR Rule, which may result in updates to estimated costs as well as identification of additional required corrective actions.

Clean Water Act Section 316(b) — The Federal Clean Water Act requires the EPA to regulate cooling water intake structures to assure they reflect the best technology available for minimizing impingement and entrainment of aquatic species.

NSP-Wisconsin estimates capital expenditures of approximately $4 million may be required to comply with the requirements. NSP-Wisconsin believes two plants could be required to make improvements to reduce impingement and entrainment. NSP-Wisconsin anticipates these costs will be recoverable through regulatory mechanisms.

Air

Clean Air Act NOx Allowance Allocations — In June 2023, the EPA published final regulations for ozone under the “Good Neighbor” provisions of the Clean Air Act that established NOx allowance budgets for fossil fuel-fired electric generating facilities in subject states. The final rule applies to generation facilities in Wisconsin, as well as other states outside of our service territory. Compliance would require subject facilities to secure additional allowances, install NOx controls and/or develop a strategy of operations that utilizes the existing allowance allocations.

While the financial impacts of the final rule are uncertain and dependent on market forces and anticipated generation, NSP-Wisconsin anticipates the annual costs could be significant, but would be recoverable through regulatory mechanisms.

10. Segment Information

Segment information and reconciliation to NSP-Wisconsin's consolidated net income:

	Three Months Ended March 31, 2025
(Millions of Dollars)	Regulated electric utility		Regulated natural gas utility		Total segments
Operating revenues (a)	$	259	$	68	$	327
Electric fuel and purchased power	106		—		106
Cost of natural gas sold and transported	—		33		33
O&M expenses	55		8		63
Depreciation and amortization	41		8		49
Other segment expenses, net	6		—		6
Interest charges and financing costs	14		2		16
Income tax expense	8		4		12
Net income	$	29	$	13	$	42
Total segment net income					$	42
Non-segment net income					—
Consolidated net income					$	42

(a)Operating revenues include $56 million of affiliate electric revenue.

	Three Months Ended March 31, 2024
(Millions of Dollars)	Regulated electric utility		Regulated natural gas utility		Total segments
Operating revenues (a)	$	256	$	54	$	310
Electric fuel and purchased power	107		—		107
Cost of natural gas sold and transported	—		24		24
O&M expenses	49		7		56
Depreciation and amortization	38		7		45
Other segment expenses, net	7		2		9
Interest charges and financing costs	12		1		13
Income tax expense	10		3		13
Net income	$	33	$	10	$	43
Total segment net income					$	43
Non-segment net income					—
Consolidated net income					$	43

(a)Operating revenues include $53 million of affiliate electric revenue.

Asset and capital expenditure information is not provided for NSP-Wisconsin's reportable segments. As an integrated electric and natural gas utility, NSP-Wisconsin operates significant assets that are not dedicated to a specific business segment. Reporting assets and capital expenditures by business segment would require arbitrary and potentially misleading allocations, which may not necessarily reflect the assets that would be required for the operation of the business segments on a stand-alone basis.

Certain costs, such as common depreciation, common O&M expenses and interest expense are allocated based on cost causation allocators across each segment. In addition, a general allocator is used for certain general and administrative expenses, including office supplies, rent, property insurance and general advertising.

Other segment expenses, net, for the reportable segments includes conservation and DSM expenses, taxes (other than income taxes), other income (expense), net, intersegment expenses and AFUDC - equity.

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

Discussion of financial condition and liquidity for NSP-Wisconsin is omitted per conditions set forth in General Instructions H(1)(a) and (b) of Form 10-Q for wholly owned subsidiaries. It is replaced with management’s narrative analysis of the results of operations set forth in General Instruction H(2)(a) of Form 10-Q for wholly owned subsidiaries (reduced disclosure format).

Non-GAAP Financial Measures

The following discussion includes financial information prepared in accordance with GAAP, as well as certain non-GAAP financial measures such as ongoing earnings. Generally, a non-GAAP financial measure is a measure of a company’s financial performance, financial position or cash flows that adjusts measures calculated and presented in accordance with GAAP.

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NSP-Wisconsin’s management uses non-GAAP measures for financial planning and analysis, for reporting of results to the Board of Directors, in determining performance-based compensation and communicating its earnings outlook to analysts and investors. Non-GAAP financial measures are intended to supplement investors’ understanding of our performance and should not be considered alternatives for financial measures presented in accordance with GAAP. These measures are discussed in more detail below and may not be comparable to other companies’ similarly titled non-GAAP financial measures.

Earnings Adjusted for Certain Items (Ongoing Earnings)

Ongoing earnings reflect adjustments to GAAP earnings (net income) for certain items.

We use this non-GAAP financial measure to evaluate and provide details of NSP-Wisconsin’s core earnings and underlying performance. We believe this measurement is useful to investors to evaluate the actual and projected financial performance and contribution of NSP-Wisconsin. For the three months ended March 31, 2025 and 2024, there were no such adjustments to GAAP earnings and therefore GAAP earnings equal ongoing earnings.

Results of Operations

NSP-Wisconsin's net income was $42 million and $43 million for the three months ended March 31, 2025 and 2024. The change was driven by higher O&M expenses, depreciation, and interest charges.

Electric Revenue

Electric revenues are impacted by fluctuations in the price of natural gas, coal and uranium, regulatory outcomes, market prices and seasonality.

(Millions of Dollars)	Three Months Ended March 31, 2025 vs. 2024
Estimated impact of weather	$	4
Interchange agreement revenue from NSP-Minnesota	3
Recovery of lower cost of electric fuel and purchased power expenses	(3)
Other, net	(1)
Total increase	$	3

Natural Gas Revenues

Natural gas revenues vary with changing sales and the cost of natural gas and regulatory outcomes.

(Millions of Dollars)	Three Months Ended March 31, 2025 vs. 2024
Recovery of higher cost of natural gas	$	9
Estimated impact of weather	4
Retail sales growth	1
Total increase	$	14

Cost of Natural Gas Sold and Transported — Expenses incurred for the cost of natural gas sold are impacted by market prices and seasonality. These costs are generally recovered through various regulatory recovery mechanisms. As a result, changes in these expenses are largely offset in operating revenues and have minimal earnings impact.

Natural gas sold and transported increased $9 million year to date. The increase was primarily due to higher commodity prices and volumes.

Non-Fuel Operating Expenses and Other Items

O&M Expenses — O&M expenses increased $7 million year to date, primarily due to increased insurance costs and benefits.

Depreciation and Amortization — Depreciation and amortization increased $4 million year to date, primarily due to system expansion.

Interest Charges — Interest charges increased $4 million year to date, primarily due to increased long-term debt levels and interest rates.

Public Utility Regulation and Other

The FERC and various state and local regulatory commissions regulate NSP-Wisconsin. The electric and natural gas rates charged to customers of NSP-Wisconsin are approved by the FERC or the regulatory commissions in the states in which it operates.

Rates are designed to recover plant investment, operating costs and an allowed return on investment. NSP-Wisconsin requests changes in utility rates through commission filings.

Changes in operating costs can affect NSP-Wisconsin’s financial results, depending on the timing of rate case filings and implementation of final rates. Other factors affecting rate filings are new investments, sales, conservation and demand side management efforts, and the cost of capital. In addition, the regulatory commissions authorize the ROE, capital structure and depreciation rates in rate proceedings. Decisions by these regulators can significantly impact NSP-Wisconsin’s results of operations.

Except to the extent noted below, the circumstances set forth in Public Utility Regulation included in Item 7 of NSP-Wisconsin’s Annual Report on Form 10-K for the year ended Dec. 31, 2024 appropriately represent, in all material respects, the current status of public utility regulation and are incorporated herein by reference.

Pending Regulatory Proceedings

Excess Liability Insurance Deferral – In February 2025, NSP-Wisconsin filed a request with the PSCW for deferred accounting treatment for excess liability insurance expense of $9.6 million incurred as a result of the October 2024 policy renewal. A PSCW decision is expected in the third quarter of 2025.

Wisconsin Electric and Natural Gas Rate Case – In March 2025, NSP-Wisconsin filed a request with the PSCW for a multi-year electric and natural gas rate increase.

For the electric utility, NSP-Wisconsin is seeking a total electric revenue increase of $94 million (11.8%) in 2026 and an incremental $57 million (7.1%) in 2027, for a total of $151 million over the two-year period of 2026 and 2027. The electric rate increase is based on electric rate base of $2.9 billion in 2026 and $3.2 billion in 2027. For the natural gas utility, NSP-Wisconsin requested a total natural gas revenue increase of $20 million (12.7%) in 2026 and an incremental $4 million (1.5%) in 2027, for a total of $24 million (14.2%) over the two-year period of 2026 and 2027. The natural gas rate increase is based on natural gas rate base of $0.3 billion in 2026 and $0.4 billion in 2027. Both the electric and natural gas rate requests are based on forward-looking test years, with a 10.0% ROE and an equity ratio of 53.5%. 

The rate request is primarily driven by investments in NSP-Wisconsin’s electric and natural gas systems to enhance reliability and resiliency while ensuring safe operation. The investments also enable additional clean energy generation; the benefits of wind, solar and nuclear tax credits are incorporated in the table below.    

A PSCW decision is anticipated in the fourth quarter of 2025.

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(Millions of Dollars)	Electric		Natural Gas
NSPW rate base-related investment	$	176	$	17
Interchange agreement billings (a)	(72)		—
O&M expenses	30		10
Sales	18		(1)
Other	(1)		(2)
NSP-Wisconsin’s filed rate request	$	151	$	24

(a)The Interchange Agreement is a Federal Energy Regulatory Commission cost sharing tariff under which NSP-Wisconsin and its affiliate, NSP-Minnesota allocate the costs of the integrated electric generation and transmission system.

NSP System

Resource Acquisition — In February 2024, NSP filed its Upper Midwest Resource Plan with the MPUC. In October 2024, NSP-Minnesota filed a settlement with several parties reaching agreement on the resource plan, as well as the proposed projects to be approved in the pending 800 MW firm dispatchable resource acquisition.

In February 2025, the MPUC approved the terms of the settlement agreement, including:

•The selection of the company owned 420 MW Lyon County combustion turbine.

•The selection of the company owned 300 MW 4-hour Sherco battery energy storage system.

•Multiple PPAs to proceed to the negotiation stage.

•The addition of 3,200 MW of wind, 400 MW of solar and 600 MW of stand-alone storage to be added through 2030 based on an RFP process (a portion of which is expected to be fulfilled with the resources acquired as part of the 2024 RFPs). Of these amounts, approximately 2,800 MW of wind are projected to utilize the Minnesota Energy Connection transmission line.

•Planned life extensions of the Prairie Island and Monticello nuclear plants through the early 2050s.

Additionally, the MPUC approved life extensions of the Red Wing and Mankato RDF plants to 2037 and ordered NSP-Minnesota to file a proposed tariff for customers with super-large load, largely data centers, by July 15, 2025.

NSP-Minnesota will file additional RFPs for approved resource needs beginning in late 2025 or early 2026.

NSP-Minnesota and NSP-Wisconsin are actively engaged in multiple processes and proceedings to acquire resources to meet their identified generation resource needs.

•In October 2023, NSP-Minnesota issued an RFP seeking 1,200 MW of wind assets to replace capacity and reutilize interconnection rights associated with the retiring Sherco coal facilities. The RFP closed in December 2023. NSP-Minnesota expects to file for approval of recommended projects in summer 2025.

•In 2024, NSP-Minnesota and NSP-Wisconsin each issued an RFP collectively seeking up to 1,600 MW of wind, solar, storage or hybrid resources to interconnect to the NSP System, including reutilization of the interconnection rights associated with the retiring Sherco coal units, and 650 MW of solar and storage resources to specifically reutilize the interconnection rights associated with the retiring King coal unit. NSP-Minnesota and NSP-Wisconsin announced the short listed projects in January 2025 and plan to file for the requisite approvals of the selected resources with the MPUC and PSCW, respectively, in the second half of 2025.

Other

Supply Chain

NSP-Wisconsin’s ability to meet customer energy requirements, respond to storm-related disruptions and execute our capital expenditure program are dependent on maintaining an efficient supply chain. Manufacturing processes have experienced disruptions related to scarcity of certain raw materials and interruptions in production and shipping. These disruptions have been further exacerbated by inflationary pressures, labor shortages and the impact of international conflicts/issues. NSP-Wisconsin continues to monitor the situation as it remains fluid and seeks to mitigate the impacts by securing alternative suppliers, modifying design standards, and adjusting the timing of work.

Large global demand for energy-related infrastructure (renewables and gas generation, data centers, etc.) has stretched equipment supply chains, extended delivery dates and increased prices for items like combustion turbines, transformers and other large electrical equipment. The labor market for skilled engineering and construction resources to build renewables and gas generation has also been strained, impacting cost and availability.

Tariffs and Trade Complaints

In May 2024, the U.S. Department of Commerce announced the initiation of anti-dumping and countervailing duty investigations of CSPV cells from Cambodia, Malaysia, Thailand and Vietnam, whether or not assembled into modules.

In April 2025, the U.S. Department of Commerce announced its final determination in the countervailing duty circumvention and anti-dumping investigations. The rates will go into effect after the U.S. International Trade Commission makes its final determination, expected in the second quarter of 2025. Xcel Energy does not expect these determinations to impact its projects.

In January of 2025, the U.S. International Trade Commission made an affirmative determination in the preliminary phase of the anti-dumping and countervailing duty investigations concerning Active Anode Material, a component of lithium-ion batteries, from China. This case will be reviewed by the U.S. Department of Commerce and the International Trade Commission over the course of 2025.

In 2025, several executive orders have been issued imposing new global and country-specific tariffs on many imports, which may impact our procurement and development activities. Due to the current tariff level on Chinese products, utility-scale battery projects are at most risk to be impacted in terms of cost and/or schedule. Additionally, executive orders have been issued relating to the permitting of wind projects and the retirement of coal facilities.

NSP-Wisconsin continues to assess the impacts of these tariffs, executive orders, trade complaints and federal policies on its business, including company owned projects and PPAs. NSP-Wisconsin may seek regulatory relief, if required, in its jurisdictions.

Continued and/or further policy actions or other restrictions, disruptions in imports from key suppliers, or any new trade complaint could impact viability, timelines and costs of various projects and PPAs.

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Excess Liability Insurance Coverage

NSP-Wisconsin maintains excess liability coverage, which is intended to insure against liability to third parties. During 2024, Xcel Energy had approximately $600 million of excess liability coverage; including $520 million of wildfire coverage with an annual premium assigned to NSP-Wisconsin of approximately $3 million. Examples of claims paid under this policy include property damage or bodily injury to members of the public caused by NSP-Wisconsin’s employees, equipment or facilities. The increased wildfire liability risk and claims are driving a significant increase of premiums and reductions in insurance coverage in the excess liability markets. In October 2024, Xcel Energy renewed its excess liability coverage and now has $450 million of total coverage, including $450 million of wildfire coverage for NSP-Wisconsin. The annual premium for this excess liability insurance assigned to NSP-Wisconsin is approximately $12 million. In February 2025, NSP-Wisconsin filed a request with the PSCW seeking deferred accounting for these increased costs.

Environmental Regulation

In March 2025, the EPA announced that the agency will undertake various regulatory actions addressing a wide range of environmental regulations. This includes action on the 2024 power plant greenhouse gas regulations, 2024 amendments to the CCR Rule and the 2023 Good Neighbor Plan, though no formal actions have been taken on these regulations to date. We will continue to monitor and respond as appropriate to EPA’s administrative efforts to take action.  

Clean Air Act

Power Plant Greenhouse Gas Regulations — In April 2024, the EPA published final rules addressing control of CO2 emissions from the power sector. The rules regulate new natural gas generating units and emission guidelines for existing coal and certain natural gas generation. The rules create subcategories of coal units based on planned retirement date and subcategories of natural gas combustion turbines and combined cycle units based on utilization. The CO2 control requirements vary by subcategory. Based on current estimates and assumptions, NSP-Wisconsin has determined that there is minimal financial or operational impact associated with these requirements.

Waste-to-Energy Air Regulations — In January 2024, the EPA proposed air regulations addressing new and existing large municipal waste combustors. The proposed rules lower current emission standards for certain pollutants and would require installation of new pollution controls and/or more intense use of existing pollution controls at French Island Generating Station. Until final rules are issued, it is not certain what the impact will be on NSP-Wisconsin. NSP-Wisconsin believes that the cost of these initiatives or replacement generation would be recoverable through rates based on prior state commission practices.

Emerging Contaminants of Concern

PFAS are man-made chemicals that are widely used in consumer products and can persist and bio-accumulate in the environment. NSP-Wisconsin does not manufacture PFAS, but because PFAS are so ubiquitous in products and the environment, it may impact our operations.

In June 2024, the EPA finalized a rule that designated certain PFAS as hazardous substances under CERCLA. In July 2024, the EPA finalized another rule that set enforceable drinking water standards for certain PFAS.

Potential costs for these rules and any additional proposed regulations related to PFAS are uncertain and will be determined on a site specific basis where applicable. If costs are incurred, NSP-Wisconsin believes the costs will be recoverable through rates based on prior state commission practices.

ITEM 4 — CONTROLS AND PROCEDURES

Disclosure Controls and Procedures

NSP-Wisconsin maintains a set of disclosure controls and procedures designed to ensure that information required to be disclosed in reports that it files or submits under the Securities Exchange Act of 1934 is recorded, processed, summarized, and reported within the time periods specified in SEC rules and forms.

In addition, the disclosure controls and procedures ensure that information required to be disclosed is accumulated and communicated to management, including the CEO and CFO, allowing timely decisions regarding required disclosure.

As of March 31, 2025, based on an evaluation carried out under the supervision and with the participation of NSP-Wisconsin’s management, including the CEO and CFO, of the effectiveness of its disclosure controls and procedures, the CEO and CFO have concluded that NSP-Wisconsin’s disclosure controls and procedures were effective.

Internal Control Over Financial Reporting

No changes in NSP-Wisconsin’s internal control over financial reporting occurred during the most recent fiscal quarter that materially affected, or are reasonably likely to materially affect, NSP-Wisconsin’s internal control over financial reporting.

PART II — OTHER INFORMATION

ITEM 1 — LEGAL PROCEEDINGS

NSP-Wisconsin is involved in various litigation matters in the ordinary course of business. The assessment of whether a loss is probable or is a reasonable possibility, and whether the loss or a range of loss is estimable, often involves a series of complex judgments about future events. Management maintains accruals for losses probable of being incurred and subject to reasonable estimation.

Management is sometimes unable to estimate an amount or range of a reasonably possible loss in certain situations, including but not limited to, when (1) the damages sought are indeterminate, (2) the proceedings are in the early stages, or (3) the matters involve novel or unsettled legal theories. In such cases, there is considerable uncertainty regarding the timing or ultimate resolution of such matters, including a possible eventual loss.

For current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, would have a material effect on NSP-Wisconsin’s consolidated financial statements. Legal fees are generally expensed as incurred.

See Note 9 to the consolidated financial statements and Part I Item 2 for further information.

ITEM 1A — RISK FACTORS

NSP-Wisconsin's risk factors are documented in Item 1A of Part I of its Annual Report on Form 10-K for the year ended Dec. 31, 2024, which is incorporated herein by reference. There have been no material changes from the risk factors previously disclosed in the Form 10-K.

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ITEM 5 — OTHER INFORMATION

None of the Company’s directors or officers adopted, modified, or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement during the Company’s fiscal quarter ended March 31, 2025.

ITEM 6 — EXHIBITS

* Indicates incorporation by reference

Exhibit Number	Description	Report or Registration Statement	Exhibit Reference
3.01*	Amended and Restated Articles of Incorporation of NSP-Wisconsin, dated May 28, 1998	NSP-Wisconsin Form S-4 dated Jan. 21, 2004	3.01
3.02*	Amended and Restated Bylaws of NSP-Wisconsin, dated Jan. 25, 2019	NSP-Wisconsin Form 10-K for the year ended Dec. 31, 2018	3.02
31.01	Principal Executive Officer’s certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
31.02	Principal Financial Officer’s certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
32.01	Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
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 Schema
101.CAL	Inline XBRL Calculation
101.DEF	Inline XBRL Definition
101.LAB	Inline XBRL Label
101.PRE	Inline XBRL Presentation
104	Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

		Northern States Power Company (a Wisconsin corporation)
04/24/2025	By:	/s/ MELISSA L. OSTROM
		Melissa L. Ostrom
		Senior Vice President, Controller
		(Principal Accounting Officer)
	By:	/s/ BRIAN J. VAN ABEL
		Brian J. Van Abel
		Executive Vice President, Chief Financial Officer
		(Principal Financial Officer)

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