UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 31, 2026

Commission File Number	Exact Name of Registrant as Specified in its Charter, State or other Jurisdiction of Incorporation, Address of Principal Executive Offices, Zip Code, and Registrant's Telephone Number, Including Area Code	IRS Employer Identification No.

1-32853	DUKE ENERGY CORPORATION (a Delaware corporation) 525 South Tryon Street Charlotte, North Carolina 28202 800-488-3853	20-2777218
1-6196	PIEDMONT NATURAL GAS COMPANY, INC. (a North Carolina corporation) 525 South Tryon Street Charlotte, North Carolina 28202 800-488-3853	56-0556998

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

Registrant	Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Duke Energy	Common Stock, $0.001 par value	DUK	New York Stock Exchange LLC
Duke Energy	5.625% Junior Subordinated Debentures due September 15, 2078	DUKB	New York Stock Exchange LLC
Duke Energy	Depositary Shares each representing a 1/1,000^th interest in a share of 5.75% Series A Cumulative Redeemable Perpetual Preferred Stock, par value $0.001 per share	DUK PR A	New York Stock Exchange LLC
Duke Energy	3.10% Senior Notes due 2028	DUK 28A	New York Stock Exchange LLC
Duke Energy	3.85% Senior Notes due 2034	DUK 34	New York Stock Exchange LLC
Duke Energy	3.75% Senior Notes due 2031	DUK 31A	New York Stock Exchange LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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. ¨

Co-Registrant CIK	0000078460
Co-Registrant Amendment Flag	false
Co-Registrant Form Type	8-K
Co-Registrant DocumentPeriodEndDate	2026-03-31
Co-Registrant Written Communications	false
Co-Registrant Solicitating Materials	false
Co-Registrant PreCommencement Tender Offer	false
Co-Registrant PreCommencement Issuer Tender Offer	false
Co-Registrant Emerging Growth Company	false

Item 2.01 Completion of Acquisition or Disposition of Assets.

As previously disclosed in a Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission (the “SEC”) on July 29, 2025 by Duke Energy Corporation (“Duke Energy”) and Piedmont Natural Gas Company, Inc., a North Carolina corporation (“Piedmont”) and wholly owned subsidiary of Duke Energy, Piedmont entered into an Asset Purchase Agreement by and between Piedmont and Spire Tennessee Inc., a Delaware corporation and successor-in-interest to Spire Inc., a Missouri corporation (“Buyer”), dated as of July 27, 2025 (the “Purchase Agreement”). Subject to the terms and conditions set forth therein, Piedmont agreed to sell its Tennessee natural gas local distribution company business to Buyer (the “Transaction”). On March 31, 2026, and pursuant to the Purchase Agreement, Piedmont completed the Transaction for $2.48 billion in cash, subject to customary purchase price adjustments as set forth in the Purchase Agreement.

The unaudited pro forma financial information of Piedmont as of December 31, 2025, after giving effect to the Transaction, is filed as Exhibit 99.1 to this Current Report on Form 8-K and incorporated into this Item 2.01 by reference.

The foregoing description of the Purchase Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Purchase Agreement, a copy of which was filed as Exhibit 2.1 to Piedmont’s Form 10-Q for the quarterly period ended September 30, 2025, filed on November 7, 2025, and is incorporated herein by reference.

Item 7.01 Regulation FD Disclosure.

On March 31, 2026, Duke Energy issued a press release announcing the completion of the Transaction. A copy of the press release is attached hereto as Exhibit 99.2.

The information contained in this Item 7.01 (including Exhibit 99.2) is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities under that Section and shall not be deemed to be incorporated by reference into any filing of Duke Energy under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act.

Forward-Looking Information

This document includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Exchange Act. Forward-looking statements are based on management’s beliefs and assumptions. These forward-looking statements are identified by terms and phrases such as “anticipate,” “believe,” “intend,” “estimate,” “expect,” “continue,” “should,” “could,” “may,” “plan,” “project,” “predict,” “will,” “potential,” “forecast,” “target,” “outlook,” “guidance,” and similar expressions. Various factors may cause actual results to be materially different than the suggested outcomes within forward-looking statements; accordingly, there is no assurance that such results will be realized. These risks and uncertainties are identified and discussed in Duke Energy’s Form 10-K for the year ended December 31, 2025, and subsequent quarterly reports filed with the SEC and available at the SEC’s website at www.sec.gov. In light of these risks, uncertainties and assumptions, the events described in the forward-looking statements might not occur or might occur to a different extent or at a different time than Duke Energy has described. Duke Energy expressly disclaims an obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Item 9.01 Financial Statements and Exhibits.

(b) Pro forma financial information.

The following unaudited pro forma financial information of Piedmont, after giving effect to the Transaction, is attached hereto as Exhibit 99.1:

·	Unaudited Pro Forma Consolidated Balance Sheet of Piedmont as of December 31, 2025; and
·	Unaudited Pro Forma Consolidated Statement of Operations for the Year Ended December 31, 2025.

(d) Exhibits.

2.1	Asset Purchase Agreement, dated as of July 27, 2025, by and between Piedmont Natural Gas Company, Inc. and Spire Inc. (incorporated by reference to Exhibit 2.1 to the Quarterly Report on Form 10-Q of Piedmont Natural Gas Company, Inc. filed on November 7, 2025, File No. 001-6196).
99.1	Unaudited Pro Forma Consolidated Financial Information of Piedmont Natural Gas Company, Inc.
99.2	Press Release, dated March 31, 2026, issued by Duke Energy Corporation.
104	Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

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 hereunto duly authorized.

	DUKE ENERGY CORPORATION
	PIEDMONT NATURAL GAS COMPANY, INC.

Date: April 1, 2026	By:	/s/ David S. Maltz
		David S. Maltz
		Vice President, Legal, Chief Governance Officer and Corporate Secretary

Exhibit 99.1

SELECTED UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL DATA

On July 27, 2025, Piedmont Natural Gas Company, Inc (the “Company”, "PNG", and “our”) entered into a purchase agreement (“Purchase Agreement”) with Spire, Inc., for the sale (the “Transaction”) of our Piedmont Tennessee business ("PNG TN") with expected proceeds of $2.48 billion, subject to closing adjustments, with proceeds due at closing. The Company completed the sale on March 31, 2026. The Transaction is considered significant to the Company and is therefore reflected in these unaudited Pro Forma Consolidated Financial Statements.

The unaudited Pro Forma Consolidated Financial Statements have been derived from the Company’s historical consolidated financial statements ("PNG Historical") and give effect to the Transaction. The following unaudited Pro Forma Consolidated Statement of Operations for the year ended December 31, 2025 reflects the Company’s results as if the Transaction had occurred as of January 1, 2025. The following unaudited Pro Forma Consolidated Balance Sheet as of December 31, 2025 reflects the Company’s financial position as if the Transaction had occurred on December 31, 2025. The Transaction does not qualify as a discontinued operation as it does not represent a strategic shift that will have a major effect on the Company’s operations or financial results.

The unaudited Pro Forma Consolidated Financial Statements have been prepared based upon management’s estimates utilizing the best available information and are subject to the assumptions and adjustments described below and in the accompanying notes to the unaudited Pro Forma Consolidated Financial Statements. They are not intended to be a complete representation of the Company’s financial position or results of operations had the Transaction occurred as of the period indicated. In addition, the unaudited Pro Forma Consolidated Financial Statements are provided for illustrative and informational purposes only and are not necessarily indicative of the Company’s future results of operations or financial condition had the Transaction and related transactions been completed on the date assumed. The unaudited Pro Forma Consolidated Financial Statements should be read in conjunction with the Company’s historical consolidated financial statements and accompanying notes.

The unaudited Pro Forma Consolidated Financial Statements have been prepared in accordance with Regulation S-X Article 11, Pro Forma Financial Information.

PIEDMONT NATURAL GAS COMPANY, INC.

UNAUDITED PRO FORMA CONSOLIDATED STATEMENT OF OPERATIONS

For the Year Ended December 31, 2025

				Transaction Accounting Adjustments
(in millions)		PNG Historical		PNG TN		Notes		Other Adjustments		Notes		Pro Forma Balance
Operating Revenues
Regulated natural gas	$	2,209	$	(322	)	(a)	$	-			$	1,887
Nonregulated natural gas and other		28		(4	)	(a)		-				24
Total operating revenues		2,237		(326	)	(a)		-				1,911
Operating Expenses
Cost of natural gas		784		(99	)	(a)		-				685
Operation, maintenance and other		408		(31	)	(a)		(13	)	(k)		364
Depreciation and amortization		282		(36	)	(a)		-				246
Property and other taxes		67		(11	)	(a)		-				56
Total operating expenses		1,541		(177	)	(a)		(13	)			1,351
Gains on Sales of Other Assets and Other, net		-		-		(a)		693		(f)		693
Operating Income (Loss)		696		(149	)	(a)		706				1,253
Other Income and Expenses
Equity in earnings of unconsolidated affiliates		8		-		(a)		-				8
Other income and expenses, net		41		(4	)	(a)		-				37
Total other income and expenses		49		(4	)	(a)		-				45
Interest Expense		193		6		(a)		(22	)	(g)		177
Income (Loss) Before Income Taxes		552		(159	)	(a)		728				1,121
Income Tax Expense		112		-		(a)		122		(h)		234
Net Income (Loss) and Comprehensive (Loss) Income	$	440	$	(159	)	(a)	$	606			$	887

See accompanying Notes to the Unaudited Pro Forma Consolidated Financial Statements, which are an integral part of these statements.

PIEDMONT NATURAL GAS COMPANY, INC.

Unaudited Pro Forma Consolidated Balance Sheet

As of December 31, 2025

					Transaction Accounting Adjustments
(in millions)		PNG Historical			PNG TN		Notes		Other Adjustments		Notes		Pro Forma Balance
ASSETS
Current Assets
Cash and cash equivalents	$	1		$	-		(a)	$	1,333		(b) (c) (e)	$	1,334
Receivables (net of allowance for doubtful accounts of $6)		390			-		(a)		-				390
Receivables from affiliated companies		8			-		(a)		-				8
Inventory		77			-		(a)		-				77
Assets held for sale		109			(109	)	(a)		-				-
Regulatory assets		106			-		(a)		-				106
Other		8			-		(a)		-				8
Total current assets		699			(109	)	(a)		1,333				1,923
Property, Plant and Equipment
Cost		11,325			-		(a)		-				11,325
Accumulated depreciation and amortization		(2,168	)		-		(a)		-				(2,168	)
Net property, plant and equipment		9,157			-		(a)		-				9,157
Other Noncurrent Assets
Goodwill		39			-		(a)		-				39
Regulatory assets		350			-		(a)		-				350
Operating lease right-of-use assets, net		2			-		(a)		-				2
Investments in unconsolidated affiliates		76			-		(a)		-				76
Assets held for sale		1,864			(1,864	)	(a)		-				-
Other		283			-		(a)		-				283
Total other noncurrent assets		2,614			(1,864	)	(a)		-				750
Total Assets	$	12,470		$	(1,973	)	(a)	$	1,333			$	11,830
LIABILITIES AND EQUITY
Current Liabilities
Accounts payable	$	286		$	-		(a)	$	-			$	286
Accounts payable to affiliated companies		90			-		(a)		37		(j)		127
Notes payable to affiliated companies		609			-		(a)		(350	)	(c)		259
Taxes accrued		106			-		(a)		-				106
Interest accrued		41			-		(a)		(22	)	(g)		19
Current maturities of long-term debt		490			-		(a)		(450	)	(c)		40
Liabilities associated with assets held for sale		66			(66	)	(a)		-				-
Regulatory liabilities		20			-		(a)		-				20
Other		81			-		(a)		37		(d)		118
Total current liabilities		1,789			(66	)	(a)		(748	)			975
Long-Term Debt		3,761			-		(a)		-				3,761
Other Noncurrent Liabilities
Deferred income taxes		1,071			-		(a)		(169	)	(e)		902
Asset retirement obligations		25			-		(a)		-				25
Regulatory liabilities		802			-		(a)		(9	)	(e)		793
Operating lease liabilities		2			-		(a)		-				2
Accrued pension and other post-retirement benefit costs		7			-		(a)		-				7
Liabilities associated with assets held for sale		170			(170	)	(a)		-				-
Other		89			-		(a)		-				89
Total other noncurrent liabilities		2,166			(170	)	(a)		(178	)			1,818
Commitments and Contingencies
Equity
Common Stock, no par value, 100 shares authorized and outstanding at 2025		1,635			-		(a)		-				1,635
Retained earnings		3,118			-		(a)		522		(i)		3,640
Total Piedmont Natural Gas Company, Inc. stockholder's equity		4,753			-		(a)		522				5,275
Noncontrolling interests		1			-		(a)		-				1
Total equity		4,754			-		(a)		522				5,276
Total Liabilities and Equity	$	12,470		$	(236	)	(a)	$	(404	)		$	11,830

See accompanying Notes to the Unaudited Pro Forma Consolidated Financial Statements, which are an integral part of these statements.

NOTES TO THE UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

Transaction Accounting Adjustments to Pro Forma Consolidated Financial Statements:

(a) Adjustments represent the elimination of assets, liabilities, and results of operations of the Piedmont Tennessee business.

(b) Reflects $2.48 billion of estimated cash consideration from the disposal of the Piedmont Tennessee business less repayment of debt noted in (c) and estimated payment for taxes as noted in (e).

(d) Reflects accrual for non-recurring costs of approximately $37 million incurred after December 31, 2025, to complete the Transaction. These costs primarily relate to transaction advisory and professional fees associated with the Transaction.

(e) Reflects estimated current Income tax accrued and Deferred tax expense due to the recognition of the taxable gain resulting from the Transaction. Adjustments include $347 million offset to cash representative of decrease in accumulated deferred income tax and taxes accrued.

(f) Reflects the estimated gain recognized from the Transaction. The estimated gain was computed by taking the total consideration of $2.48 billion, less the amount of net assets sold of $1.74 billion and $50 million estimated transaction costs associated with the Transaction. The actual gain will be calculated based on the net book value as of the closing of the Transaction and therefore could differ from the current estimate. The total consideration received is subject to customary post-closing adjustments.

(g) Reflects the elimination of the related Interest expense of $22 million for the twelve months ended December 31, 2025 to give effect to the repayment of debt.

(h) Reflects the income tax effect of the pro forma adjustments calculated using the applicable statutory tax rates in effect within the respective tax jurisdictions during the periods presented. The estimated federal and state statutory income tax rate is 24%.

(i) Amounts relate to adjustments to retained earnings due to gain on sale, tax impact of the gain on sale, interest expense, transaction costs, and corporate allocation costs.

(j) Adjustment to Accounts payable to affiliated companies of $37 million reflects corporate allocations for the proportionate share of corporate governance and other shared services costs, primarily related to shared support functions, office supplies, rent, as well as other third-party costs, indemnification coverages, and usage of shared office space.

(k) Reflects the reclassification of transaction costs of $13 million incurred prior to December 31, 2025, to offset the gain on sale.

Exhibit 99.2

Media Contact: Gillian Moore

24-hour: 800.559.3853

Analyst Contact: Mike Switzer

Office: 704.382.6473

March 31, 2026

Duke Energy completes sale of its Tennessee Piedmont Natural Gas business to Spire

·	Close of transaction previously announced in July 2025
·	Proceeds to help fund industry’s largest regulated capital plan

CHARLOTTE, N.C. – Duke Energy (NYSE: DUK) today announced it has completed the sale of its Tennessee Piedmont Natural Gas business to Spire – one of the largest publicly traded natural gas companies in the country – for $2.48 billion. The agreement was previously announced on July 29, 2025.

Approximately $800 million of the proceeds will be used to pay down debt at Piedmont Natural Gas to maintain its capital structure. The remaining $1.5 billion proceeds, net of tax, will help efficiently fund the industry’s largest regulated capital plan – $103 billion of investments over the next five years – to support a growing system and serve increasing load while keeping customer costs as low as possible.

“Today marks a significant milestone with the successful transition of our Tennessee natural gas business to Spire,” said Harry Sideris, Duke Energy president and chief executive officer. “As we enter a period of record investment, this transaction helps efficiently fund our capital plan – a plan built on safely and reliably meeting our communities’ growing energy needs while managing costs for our more than 10 million customers.”

Sideris added, “I want to thank our Tennessee natural gas teammates for their commitment to industry-leading customer service, safety and operational excellence, as well as the Nashville community for trusting us to serve its growing energy needs for more than 40 years. Spire will carry forward best-in-class service and continue delivering value for Tennessee employees, customers and communities.”

“We’re pleased to welcome Piedmont customers and employees in Tennessee to Spire,” said Scott Doyle, president and chief executive officer of Spire. “This acquisition allows us to expand our core utility business while continuing to do what we do best as a company – safely delivering reliable natural gas to the communities we serve.”

The sale agreement for the Piedmont Natural Gas Tennessee business included nearly 3,800 miles of distribution and transmission pipelines serving more than 200,000 customers. The primary operations will remain in the Greater Nashville area, and the Piedmont Natural Gas employees who primarily support the business have transitioned to Spire to maintain business continuity for its operations and customers.

JP Morgan Securities LLC and RBC Capital Markets LLC served as Duke Energy's financial advisors. Skadden, Arps, Slate, Meagher & Flom LLP served as Duke Energy's transactional legal advisor. In addition, Duke Energy received legal support on certain matters from Holland & Knight. McGuireWoods acted as joint regulatory counsel for both Duke Energy and Spire.

Duke Energy

Duke Energy (NYSE: DUK), a Fortune 150 company headquartered in Charlotte, N.C., is one of America’s largest energy holding companies. The company’s electric utilities serve 8.7 million customers in North Carolina, South Carolina, Florida, Indiana, Ohio and Kentucky, and collectively own 55,700 megawatts of energy capacity. Its natural gas utilities serve 1.6 million customers in North Carolina, South Carolina, Ohio and Kentucky.

Duke Energy is executing an energy modernization strategy, keeping customer value at the forefront as it invests in electric grid upgrades and efficient generation resources to strengthen the system and serve growing energy needs.

More information is available at duke-energy.com. Follow Duke Energy on X, LinkedIn, Instagram, TikTok and Facebook for stories about the people and innovations powering its communities.

Piedmont Natural Gas

Piedmont Natural Gas, a subsidiary of Duke Energy, distributes natural gas to more than 1 million residential, commercial, industrial and power generation customers in North Carolina and South Carolina. More information: piedmontng.com. Follow Piedmont Natural Gas: Facebook.

Spire

Spire Inc. (NYSE: SR) believes energy exists to help make people's lives better. It's a simple idea, but one that's at the heart of Spire's company. Every day Spire serves close to 2 million homes and businesses, making it one of the largest publicly traded natural gas companies in the country. Spire helps families and business owners fuel their daily lives through its gas utilities serving Alabama, Mississippi, Missouri and Tennessee. Its natural gas-related businesses include Spire Marketing and Spire Midstream. Spire is committed to transforming its business through growing organically, investing in infrastructure, and driving continuous improvement. Learn more at SpireEnergy.com.

Forward-Looking Information

This document includes forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Forward-looking statements are based on management’s beliefs and assumptions. These forward-looking statements are identified by terms and phrases such as "anticipate," "believe," "intend," "estimate," "expect," "continue," "should," "could," "may," "plan," "project," "predict," "will," "potential," "forecast," "target," "outlook," "guidance," and similar expressions. Various factors may cause actual results to be materially different than the suggested outcomes within forward-looking statements; accordingly, there is no assurance that such results will be realized. These risks and uncertainties are identified and discussed in Duke Energy’s Form 10-K for the year ended December 31, 2025, and subsequent quarterly reports filed with the U.S. Securities and Exchange Commission (the “SEC”) and available at the SEC’s website at www.sec.gov. In light of these risks, uncertainties and assumptions, the events described in the forward-looking statements might not occur or might occur to a different extent or at a different time than Duke Energy has described. Duke Energy expressly disclaims an obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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