0001692115-25-000149 | 10-Q | XBRL Viewer | Southwest GAS Holdings INC

Debt (Tables)

9 Months Ended

Sep. 30, 2025

Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt

Details surrounding the fair value and individual carrying values of instruments are provided in the table that follows.


	September 30, 2025				December 31, 2024
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
(Thousands of dollars)
Southwest Gas Holdings, Inc. and Southwest Gas Corporation:
Southwest Gas long-term debt	$	3,532,500	$	3,236,584	$	3,532,500	$	3,121,449
Unamortized discount and debt issuance costs	(25,380)				(28,023)
Southwest Gas Holdings, Inc. and Southwest Gas Corporation total long-term debt (no current maturities)	$	3,507,120			$	3,504,477

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Regulated operations revenues	$ 316,911	$ 359,131	$ 1,459,645	$ 1,922,157
Operating expenses:
Net cost of gas sold	42,685	111,712	429,398	984,188
Operations and maintenance	134,777	130,861	402,945	394,957
Depreciation and amortization	79,073	74,153	241,703	220,663
Taxes other than income taxes	23,368	22,283	70,379	66,414
Total operating expenses	279,903	339,009	1,144,425	1,666,222
Operating income	37,008	20,122	315,220	255,935
Other income and (expenses):
Net interest deductions	(49,003)	(53,806)	(156,787)	(152,452)
Other income	15,367	16,599	42,629	48,918
Total other (expenses)	(33,636)	(37,207)	(114,158)	(103,534)
Income (loss) from continuing operations before income taxes	3,372	(17,085)	201,062	152,401
Income tax expense (benefit)	(803)	(7,858)	36,059	18,259
Net income	270,476	289	371,463	106,359
Southwest Gas Corporation
Regulated operations revenues	316,911	359,131	1,459,645	1,922,157
Operating expenses:
Net cost of gas sold	42,685	111,712	429,398	984,188
Operations and maintenance	133,808	129,736	399,867	390,229
Depreciation and amortization	79,073	74,153	241,703	220,663
Taxes other than income taxes	23,368	22,283	70,379	66,414
Total operating expenses	278,934	337,884	1,141,347	1,661,494
Operating income	37,977	21,247	318,298	260,663
Other income and (expenses):
Net interest deductions	(46,156)	(42,312)	(135,524)	(118,595)
Other income	13,277	16,665	40,385	48,976
Total other (expenses)	(32,879)	(25,647)	(95,139)	(69,619)
Income (loss) from continuing operations before income taxes	5,098	(4,400)	223,159	191,044
Income tax expense (benefit)	(422)	(4,972)	41,020	27,053
Net income	$ 5,520	$ 572	$ 182,139	$ 163,991

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2025	Oct. 31, 2025
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2025
Document Transition Report	false
Entity File Number	001-37976
Entity Registrant Name	Southwest Gas Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3881866
Entity Address, Address Line One	8360 S. Durango Drive
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89113
City Area Code	(702)
Local Phone Number	876-7237
Title of 12(b) Security	Southwest Gas Holdings, Inc. Common Stock, $1 Par Value
Trading Symbol	SWX
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		72,182,840
Entity Central Index Key	0001692115
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q3
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Southwest Gas Corporation
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2025
Document Transition Report	false
Entity File Number	1-7850
Entity Registrant Name	Southwest Gas Corporation
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	88-0085720
Entity Address, Address Line One	8360 S. Durango Drive
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89113
City Area Code	(702)
Local Phone Number	876-7237
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0000092416
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q3
Amendment Flag	false
Current Fiscal Year End Date	--12-31

Centuri Separation - Schedule of Net Gain from Discontinued Operation (Details) - Centuri - Discontinued Operations, Disposed of by Sale - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 11, 2025	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair value of the retained investment in Centuri	$ 533,636
Net proceeds received from the August 11, 2025 public offering and private placement	355,220
Carrying value of noncontrolling interest attributable to Centuri prior to deconsolidation	460,897
Less: Carrying value of Centuri net assets prior to deconsolidation, including AOCI	(982,396)
Gain on deconsolidation of Centuri before income tax	367,357	$ 367,357	$ 0	$ 367,357	$ 0
Income tax expense	88,566
Gain on deconsolidation of Centuri, net of tax	278,791
Gain on interest sold	136,900
Gain on the investment retained	$ 230,400

Centuri Separation - Schedule of Net Proceeds from Sale of Stock (Details) - USD ($) $ in Millions						3 Months Ended
	Sep. 05, 2025	Aug. 11, 2025	Jul. 08, 2025	Jun. 18, 2025	May 22, 2025	Sep. 05, 2025
Public Offering And Private Placement
Subsidiary or Equity Method Investee [Line Items]
Net proceeds from sale of stock		$ 355.2			$ 224.6	$ 1,349.9
Public Offering
Subsidiary or Equity Method Investee [Line Items]
Net proceeds from sale of stock	$ 524.0			$ 224.1
Private Placement
Subsidiary or Equity Method Investee [Line Items]
Net proceeds from sale of stock			$ 22.0

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - Southwest - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Amortization of prior service cost, tax	$ 11	$ 11	$ 33	$ 33
Amortization of net actuarial loss, tax	226	458	678	1,375
Regulatory adjustment, tax	(153)	(347)	(457)	(1,043)
Southwest Gas Corporation
Amortization of prior service cost, tax	11	11	33	33
Amortization of net actuarial loss, tax	226	458	678	1,375
Regulatory adjustment, tax	$ (153)	$ (347)	$ (457)	$ (1,043)

Background and Organization	9 Months Ended
Background and Organization	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Organization	Note 1 – Background and Organization Nature of Operations. The Company, a Delaware corporation, is a holding company owning all of the shares of common stock of Southwest Gas; and until April 22, 2024, all of the shares of common stock of Centuri. The Company’s common stock trades under the ticker symbol “SWX.” The Company’s businesses were managed within two separate reportable segments until August 2025, our Natural Gas Distribution segment (Southwest Gas) and our Utility Infrastructure Services segment (Centuri). After August 2025, our business is solely comprised of our Natural Gas Distribution segment (see Note 7 – Segment Information). Southwest Gas is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest Gas are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. While mechanisms exist in all states in which Southwest Gas operates, which decouple authorized operating cost recovery and profitability from the volume of natural gas sold, thereby also incentivizing energy conservation, results for the Natural Gas Distribution segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures. As part of a simplification strategy, the Company previously communicated that it would pursue a separation of Centuri. In April 2024, the Company and Centuri announced the completion of the Centuri IPO. Following the Centuri IPO, the Company owned approximately 81% of Centuri. From May 2025 through September 2025, the Company completed a series of secondary public offerings and private placements of its holdings of Centuri common stock and, on September 5, 2025, completed a sale of its remaining shares. The Company’s sale of Centuri (which represents the entirety of the Company’s Utility Infrastructure Services segment) met the criteria to be presented as discontinued operations in accordance with U.S. GAAP. See also Note 2 – Summary of Significant Accounting Policies and Note 6 - Centuri Separation.

CONDENSED CONSOLIDATED BALANCE SHEETS - Southwest - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Regulated operations plant:
Gas plant	$ 11,289,621	$ 10,844,895
Less: accumulated depreciation	(3,025,110)	(2,914,457)
Construction work in progress	231,095	178,647
Net regulated operations plant	8,495,606	8,109,085
Other property and investments, net	172,494	165,448
Current assets:
Cash and cash equivalents	778,631	314,770
Accounts receivable, net of allowances	110,575	203,012
Accrued utility revenue	51,700	96,600
Deferred purchased gas costs	99	13,807
Materials, supplies, and gas inventories	91,154	93,755
Prepaid and other current assets	211,334	141,017
Total current assets	1,243,493	1,464,345
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	405,831	395,747
Total noncurrent assets	416,986	2,334,028
Total assets	10,328,579	12,072,906
Capitalization, Long-Term Debt and Equity [Abstract]
Common stock	73,811	73,413
Additional paid-in capital	2,893,066	2,721,343
Accumulated other comprehensive loss, net	(37,597)	(49,218)
Retained earnings	999,399	758,649
Total equity attributable to Southwest Gas Holdings, Inc. stockholders	3,928,679	3,504,187
Long-term debt, less current maturities	3,507,120	3,504,477
Total capitalization	7,435,799	7,193,559
Current liabilities:
Accounts payable	118,932	190,918
Customer deposits	67,026	63,876
Accrued general taxes	58,594	59,353
Accrued interest	38,503	35,668
Deferred purchased gas costs	356,458	255,398
Dividends declared	44,752	44,505
Other current liabilities	112,519	119,357
Total current liabilities	804,703	1,831,967
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	905,604	857,982
Accumulated removal costs	490,000	472,000
Other deferred credits and other long-term liabilities	692,473	700,672
Total deferred income taxes and other credits	2,088,077	3,047,380
Total capitalization and liabilities	10,328,579	12,072,906
Southwest Gas Corporation
Regulated operations plant:
Gas plant	11,289,621	10,844,895
Less: accumulated depreciation	(3,025,110)	(2,914,457)
Construction work in progress	231,095	178,647
Net regulated operations plant	8,495,606	8,109,085
Other property and investments, net	166,135	159,678
Current assets:
Cash and cash equivalents	181,996	311,073
Accrued utility revenue	51,700	96,600
Income taxes receivable, net	931	0
Deferred purchased gas costs	99	13,807
Materials, supplies, and gas inventories	91,154	93,755
Prepaid and other current assets	210,984	140,873
Total current assets	648,874	859,055
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	403,707	394,852
Total noncurrent assets	414,862	406,007
Total assets	9,725,477	9,533,825
Capitalization, Long-Term Debt and Equity [Abstract]
Common stock	49,112	49,112
Additional paid-in capital	2,171,752	2,165,002
Accumulated other comprehensive loss, net	(37,597)	(38,401)
Retained earnings	1,233,196	1,096,149
Total equity attributable to Southwest Gas Holdings, Inc. stockholders	3,416,463	3,271,862
Long-term debt, less current maturities	3,507,120	3,504,477
Total capitalization	6,923,583	6,776,339
Current liabilities:
Customer deposits	67,026	63,876
Accrued general taxes	58,594	59,353
Accrued interest	38,503	35,460
Deferred purchased gas costs	356,458	255,398
Dividends declared	0	44,600
Other current liabilities	112,466	119,357
Total current liabilities	751,278	769,026
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	872,344	819,973
Accumulated removal costs	490,000	472,000
Other deferred credits and other long-term liabilities	688,272	696,487
Total deferred income taxes and other credits	2,050,616	1,988,460
Total capitalization and liabilities	9,725,477	9,533,825
Southwest Gas Corporation \| Related Party
Current assets:
Accounts receivable, net of allowances	1,435	0
Current liabilities:
Accounts payable	0	370
Southwest Gas Corporation \| Nonrelated Party
Current assets:
Accounts receivable, net of allowances	110,575	202,947
Current liabilities:
Accounts payable	$ 118,231	$ 190,612

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2025
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Justin L. Brown [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	On September 10, 2025, Justin L. Brown, President of Southwest Gas Corporation, adopted a new Rule 10b5-1 trading arrangement intended to satisfy the affirmative defense conditions of Rule 10b5–1(c) of the Exchange Act. Mr. Brown’s trading arrangement is scheduled to terminate on January 7, 2028, subject to early termination for certain specified events set forth in the trading arrangement. The trading arrangement is intended to permit Mr. Brown to sell up to (i) 75% of the net after-tax shares of common stock to be received as a result of the vesting on January 4, 2026 of an aggregate of up to 6,509.393 restricted stock units (“RSUs”), (ii) 75% of the net after-tax shares of common stock to be received as a result of the vesting on January 4, 2027 of an aggregate of up to 4,011.997 RSUs and (iii) 75% of the net after-tax shares of common stock to be received as a result of the vesting on January 4, 2028 of an aggregate of up to 1,911.622 RSUs. The actual number of net after-tax shares to be received will vary based on the market price of our common stock at the time of settlement. Mr. Brown’s Rule 10b5-1 trading arrangement described above was adopted and precleared in accordance with Southwest Gas Holdings’ Insider Trading Policy and actual sale transactions made pursuant to such trading arrangement will be disclosed publicly in future Exchange Act Section 16 filings with the U.S. SEC.
Name	Justin L. Brown
Title	President of Southwest Gas Corporation
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 10, 2025
Expiration Date	January 7, 2028
Arrangement Duration	849 days

Debt - Narrative (Details) - USD ($)		1 Months Ended	9 Months Ended
Debt - Narrative (Details) - USD ($)	Sep. 30, 2025	Jun. 30, 2025	Sep. 30, 2025	Aug. 31, 2025	May 31, 2025	Dec. 31, 2024	Aug. 31, 2024
Debt Instrument [Line Items]
Short-term debt	$ 0		$ 0			$ 680,000,000
Weighted average interest rate						5.63%
Secured Debt \| Line of Credit
Debt Instrument [Line Items]
Debt instrument face amount							$ 550,000,000
Short-term debt	0		0	$ 225,000,000	$ 225,000,000		$ 550,000,000
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	400,000,000		400,000,000
Long-term debt outstanding	0		$ 0
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Southwest Gas Corporation \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on variable rate			1.125%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Southwest Gas Corporation \| Base Rate
Debt Instrument [Line Items]
Debt, basis spread on variable rate			0.125%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 300,000,000
Interest period		7 days
Long-term debt outstanding	$ 0		$ 0
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Commitment fee, unfunded portion		0.075%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Commitment fee, unfunded portion		0.20%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on interest variable rate		0.03839%
Debt, basis spread on variable rate	1.25%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit \| Base Rate
Debt Instrument [Line Items]
Debt, basis spread on variable rate	0.25%
Revolving Credit Agreement Due August 2029 \| Revolving Credit Facility \| Line of Credit \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 150,000,000		150,000,000
Interest period		7 days
Revolving Credit Agreement Due August 2029 \| Bridge Loan \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	30,000,000		30,000,000
Revolving Credit Agreement Due August 2029 \| Line of Credit \| Revolving Credit Facility \| Line of Credit \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 250,000,000		$ 250,000,000
Revolving Credit Agreement Due August 2029 \| Line of Credit \| Bridge Loan \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 30,000,000
Revolving Credit Agreement Due August 2029 \| Line of Credit \| Bridge Loan \| Southwest Gas Corporation \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on interest variable rate		0.03839%
Revolving Credit Agreement Due December 2026 \| Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 300,000,000

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 267,959	$ 2,663	$ 366,817	$ 110,435
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11, $11, $33 and $33, respectively	33	33	99	99
Amortization of net actuarial loss, net of tax of $226, $458, $678 and $1,375, respectively	717	1,452	2,152	4,355
Regulatory adjustment, net of tax of ($153), ($347), ($457) and ($1,043), respectively	(481)	(1,101)	(1,447)	(3,300)
Net defined benefit pension plans, net of tax	269	384	804	1,154
Other comprehensive income (loss) related to discontinued operations	(1,662)	1,675	5,153	(2,296)
Total other comprehensive income (loss), net of tax	(1,393)	2,059	5,957	(1,142)
Comprehensive income	266,566	4,722	372,774	109,293
Comprehensive income (loss) attributable to noncontrolling interests	(3,313)	2,693	(4,357)	4,226
Comprehensive income attributable to Southwest Gas Holdings, Inc.	$ 269,879	$ 2,029	$ 377,131	$ 105,067

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Aug. 11, 2025	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Significant Accounting Policies [Line Items]
Regulatory asset		$ 82.7		$ 82.7		$ 32.4
Effective income tax rate		(23.80%)	46.00%	17.90%	12.00%
Public Offering And Private Placement
Significant Accounting Policies [Line Items]
Sale of stock, number of shares	18,823,500
Southwest Gas Corporation
Significant Accounting Policies [Line Items]
Effective income tax rate		(8.30%)	113.00%	18.40%	14.20%

Centuri Separation- Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands							1 Months Ended				3 Months Ended		9 Months Ended
	Sep. 05, 2025	Aug. 11, 2025	Jul. 08, 2025	Jun. 18, 2025	May 22, 2025	Feb. 24, 2025	Sep. 05, 2025	Jul. 31, 2025	Jun. 30, 2025	May 31, 2025	Sep. 30, 2025	Sep. 05, 2025	Sep. 30, 2025	Aug. 01, 2025	Apr. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense related to outside basis of investment											$ 14,400		$ 66,800
Income tax benefit related to deferred tax assets											15,700		22,700
Net tax (benefit) expense											$ (1,300)		$ 44,100
Tax assets agreement, capital contribution						$ 56,400
Centuri
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity method investment, ownership percentage		30.90%
Realized gain (loss) on disposal of equity method investment	$ (9,700)	$ 230,400					$ 220,700
Centuri
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage by parent														52.10%	81.00%
Public Offering, Including Over-Allotment Option
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, number of shares									11,212,500	10,350,000
Sale of stock, price per share (in USD per share)									$ 20.75	$ 17.50
Stock issuance costs									$ 8,600	$ 6,600
Net proceeds from sale of stock									$ 224,100	$ 224,600
Over-Allotment Option
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, number of shares									1,462,500	1,350,000
Private Placement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sale of stock			$ 22,000
Public Offering And Private Placement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, number of shares		18,823,500
Sale of stock, price per share (in USD per share)		$ 19.50
Stock issuance costs		$ 11,800
Net proceeds from sale of stock		$ 355,200			$ 224,600							$ 1,349,900
Public Offering
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, number of shares	27,362,210
Sale of stock, price per share (in USD per share)	$ 19.18						$ 19.18					$ 19.18
Stock issuance costs	$ 900
Net proceeds from sale of stock	$ 524,000			$ 224,100
Ichan Partners LP & Ichan Partners Master Fund LP \| Private Placement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, number of shares								1,060,240		2,857,142
Net proceeds from sale of stock								$ 22,000

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($)
$ in Thousands

Total

Parent

Common stock shares

Additional Paid-in Capital

AOCI

Retained Earnings

Noncontrolling Interest

Beginning balance (in shares) at Dec. 31, 2023

71,564,000

Beginning balance at Dec. 31, 2023

$ 3,310,036

$ 73,194

$ 2,541,790

$ (43,787)

$ 738,839

$ 0

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

87,737

Common stock issuances (in shares)

101,000

Common stock issuances

1,609

$ 101

1,508

Dividends declared

(44,699)

Promissory notes in association with redeemable noncontrolling interest

4,187

Foreign currency exchange translation adjustment

(2,819)

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

384

Redemption value adjustments

(194)

Ending balance (in shares) at Mar. 31, 2024

71,665,000

Ending balance at Mar. 31, 2024

3,356,241

$ 73,295

2,547,485

(46,222)

781,683

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

18,333

1,867

Common stock issuances (in shares)

44,000

Common stock issuances

7,946

$ 44

7,902

Dividends declared

(44,649)

Centuri IPO

327,992

155,491

154,287

1,204

172,501

Foreign currency exchange translation adjustment

(1,152)

(983)

(169)

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

386

Ending balance (in shares) at Jun. 30, 2024

71,709,000

Ending balance at Jun. 30, 2024

3,666,964

3,492,765

$ 73,339

2,709,674

(45,615)

755,367

174,199

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

289

2,339

Common stock issuances (in shares)

31,000

Common stock issuances

5,315

$ 31

5,284

Dividends declared

(44,716)

Foreign currency exchange translation adjustment

1,675

1,356

319

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

384

Ending balance (in shares) at Sep. 30, 2024

71,740,000

Ending balance at Sep. 30, 2024

$ 3,632,250

3,455,393

$ 73,370

2,714,958

(43,875)

710,940

176,857

Beginning balance (in shares) at Dec. 31, 2024

71,782,756

71,783,000

Beginning balance at Dec. 31, 2024

$ 3,681,422

3,504,187

$ 73,413

2,721,343

(49,218)

758,649

177,235

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

113,870

(4,696)

Common stock issuances (in shares)

128,000

Common stock issuances

5,543

$ 128

5,415

Dividends declared

(45,066)

Foreign currency exchange translation adjustment

104

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

268

Ending balance (in shares) at Mar. 31, 2025

71,911,000

Ending balance at Mar. 31, 2025

3,751,445

3,578,886

$ 73,541

2,726,758

(48,866)

827,453

172,559

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

(12,883)

2,528

Common stock issuances (in shares)

67,000

Common stock issuances

7,083

$ 67

7,016

Dividends declared

(44,847)

Centuri stock sales and other

^[1]

405,501

140,505

138,907

1,598

264,996

Foreign currency exchange translation adjustment

6,711

5,646

1,065

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

267

Ending balance (in shares) at Jun. 30, 2025

71,978,000

Ending balance at Jun. 30, 2025

4,115,805

3,674,657

$ 73,608

2,872,681

(41,355)

769,723

441,148

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Net income (loss)

270,476

(2,526)

Common stock issuances (in shares)

203,000

Common stock issuances

18,708

$ 203

18,505

Dividends declared

(45,016)

Centuri stock sales and other

^[1]

20,569

6,096

1,880

4,216

14,473

Centuri deconsolidation

(447,944)

4,355

(452,299)

Foreign currency exchange translation adjustment

(1,662)

(866)

(796)

Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax

$ 269

269

Ending balance (in shares) at Sep. 30, 2025

72,180,889

72,181,000

Ending balance at Sep. 30, 2025

$ 3,928,679

$ 73,811

$ 2,893,066

$ (37,597)

$ 999,399

$ 0

[1]	(1) Includes the impact of the contributed Tax Assets - see Note 6 - Centuri Separation.

Components of Net Periodic Benefit Cost

9 Months Ended

Sep. 30, 2025

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost

Note 5 – Components of Net Periodic Benefit Cost

The components of Southwest Gas' net periodic benefit cost for its QRP, SERP, and PBOP for the three and nine months ended September 30, 2025 and 2024 are presented in the following tables.


	Three Months Ended September 30,
	2025						2024
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	6,099	$	58	$	292	$	7,063	$	61	$	322
Interest cost	16,397		596		856		15,097		542		794
Expected return on plan assets	(22,582)		—		(623)		(21,953)		—		(565)
Amortization of prior service costs	—		—		44		—		—		44
Amortization of net actuarial loss (gain)	751		270		(78)		1,577		333		—
Net periodic benefit cost	$	665	$	924	$	491	$	1,784	$	936	$	595

	Nine Months Ended September 30,
	2025						2024
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	18,296	$	174	$	876	$	21,189	$	183	$	966
Interest cost	49,191		1,788		2,569		45,291		1,626		2,383
Expected return on plan assets	(67,745)		—		(1,871)		(65,859)		—		(1,695)
Amortization of prior service costs	—		—		132		—		—		132
Amortization of net actuarial loss (gain)	2,255		810		(235)		4,731		999		—
Net periodic benefit cost	$	1,997	$	2,772	$	1,471	$	5,352	$	2,808	$	1,786

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Operating revenues:
Regulated operations revenues	$ 316,911	$ 359,131	$ 1,459,645	$ 1,922,157
Total operating revenues	316,911	359,131	1,459,645	1,922,157
Operating expenses:
Net cost of gas sold	42,685	111,712	429,398	984,188
Operations and maintenance	134,777	130,861	402,945	394,957
Depreciation and amortization	79,073	74,153	241,703	220,663
Taxes other than income taxes	23,368	22,283	70,379	66,414
Total operating expenses	279,903	339,009	1,144,425	1,666,222
Operating income	37,008	20,122	315,220	255,935
Other income and (expenses):
Net interest deductions	(49,003)	(53,806)	(156,787)	(152,452)
Other income	15,367	16,599	42,629	48,918
Total other (expenses)	(33,636)	(37,207)	(114,158)	(103,534)
Income (loss) from continuing operations before income taxes	3,372	(17,085)	201,062	152,401
Income tax expense (benefit)	(803)	(7,858)	36,059	18,259
Income (loss) from continuing operations	4,175	(9,227)	165,003	134,142
Income (loss) from discontinued operations, net of income tax	263,784	11,890	201,814	(23,707)
Net income	267,959	2,663	366,817	110,435
Net income (loss) attributable to noncontrolling interests	(2,517)	2,374	(4,646)	4,076
Net income	$ 270,476	$ 289	$ 371,463	$ 106,359
Basic earnings (loss) per share:
Continuing operations (in USD per share)	$ 0.06	$ (0.13)	$ 2.29	$ 1.87
Discontinued operations (in USD per share)	3.69	0.13	2.86	(0.39)
Net earnings per share - basic (in USD per share)	3.75	0	5.15	1.48
Diluted earnings (loss) per share:
Continuing operations (in USD per share)	0.06	(0.13)	2.28	1.87
Discontinued operations (in USD per share)	3.68	0.13	2.86	(0.39)
Net earnings per share - diluted (in USD per share)	$ 3.74	$ 0	$ 5.14	$ 1.48
Weighted average shares:
Basic (in shares)	72,209	71,880	72,104	71,816
Diluted (in shares)	72,405	72,086	72,265	71,994

Summary of Significant Accounting Policies - Schedule of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Accounting Policies [Abstract]
Weighted average basic shares (in shares)	72,209	71,880	72,104	71,816
Effect of dilutive securities:
Restricted stock units (in shares)	196		161	178
Weighted average diluted shares (in shares)	72,405	72,086	72,265	71,994
Number of performance share units granted (in shares)	161	165	136	148
Anti-dilutive restricted stock (in shares)		206		178

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - Southwest - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 366,817	$ 110,435
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	241,703	220,663
Deferred income taxes	48,141	38,601
Gain on sale of property	(1,604)	0
Changes in undistributed stock compensation	9,992	8,021
Equity AFUDC	(4,412)	(5,548)
Changes in current assets and liabilities:
Accounts receivable, net of allowance	92,437	137,655
Accrued utility revenue	44,900	45,200
Deferred purchased gas costs	114,768	678,478
Accounts payable	(65,842)	(103,869)
Accrued taxes	(364)	8,193
Other current assets and liabilities	(73,000)	(37,508)
Changes in deferred charges and other assets	(42,386)	(37,054)
Changes in other liabilities and deferred credits	(20,200)	(24,496)
Net cash provided by operating activities	474,508	1,154,336
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures and property additions	(570,351)	(643,720)
Proceeds from the sale of property	5,306	21,377
Changes in customer advances	3,246	(4,804)
Other	307	(884)
Net cash provided (used) in investing activities	215,186	(687,322)
CASH FLOW FROM FINANCING ACTIVITIES:
Dividends paid	(133,855)	(133,285)
Withholding remittance - share-based compensation	(2,613)	(1,800)
Other, including principal payments on finance leases	(4,283)	(3,636)
Net cash used in financing activities	(274,725)	(116,765)
Change in cash and cash equivalents, including discontinued operations	414,842	350,107
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	192,076	204,135
Income taxes paid, net	29,237	8,108
Decrease of capital expenditures in Accounts payable or Other current liabilities	(9,986)	(28,087)
Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	182,139	163,991
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	241,703	220,663
Deferred income taxes	52,890	47,061
Gain on sale of property	(1,604)	0
Changes in undistributed stock compensation	8,879	6,901
Equity AFUDC	(4,412)	(5,548)
Changes in current assets and liabilities:
Accounts receivable, net of allowance	92,372	137,635
Accrued utility revenue	44,900	45,200
Deferred purchased gas costs	114,768	678,478
Accounts payable	(66,237)	(103,708)
Accrued taxes	(1,757)	5,935
Other current assets and liabilities	(74,382)	(38,518)
Changes in deferred charges and other assets	(42,684)	(39,098)
Changes in other liabilities and deferred credits	(20,216)	(24,537)
Net cash provided by operating activities	526,359	1,094,455
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures and property additions	(570,351)	(643,720)
Proceeds from the sale of property	5,306	21,377
Changes in customer advances	3,246	(4,804)
Other	940	244
Net cash provided (used) in investing activities	(560,859)	(626,903)
CASH FLOW FROM FINANCING ACTIVITIES:
Dividends paid	(89,209)	(133,500)
Withholding remittance - share-based compensation	(2,613)	(1,801)
Other, including principal payments on finance leases	(2,755)	(1,752)
Net cash used in financing activities	(94,577)	(137,053)
Change in cash and cash equivalents, including discontinued operations	(129,077)	330,499
Cash and cash equivalents, including discontinued operations, at beginning of period	311,073	71,154
Cash and cash equivalents, including discontinued operations, at end of period	181,996	401,653
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	128,858	111,610
Income taxes paid, net	1,006	0
Decrease of capital expenditures in Accounts payable or Other current liabilities	$ (800)	$ (17,000)

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2025

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2 – Summary of Significant Accounting Policies

Basis of Presentation. The condensed consolidated financial statements of the Company and Southwest Gas included herein have been prepared pursuant to the rules and regulations of the SEC. The year-end 2024 condensed consolidated balance sheet data was derived from audited financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations.

The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments, consisting of normal recurring items and estimates necessary for a fair statement of results for the interim periods, have been made.

Discontinued Operations. On August 11, 2025, the Company completed a secondary public offering and a concurrent private placement transaction with Icahn investment entities. These transactions resulted in the sale of a combined total of 18,823,500 shares of Centuri common stock previously held by the Company (see Note 6 - Centuri Separation). Following the completion of these transactions, the Company no longer maintained a controlling financial interest in Centuri. Accordingly, Centuri’s assets, liabilities, and results of operations are no longer included in the Company’s consolidated financial statements.

In addition, the sale of Centuri, which comprised the Company’s Utility Infrastructure Services segment, represents a strategic shift that has a significant impact on the Company’s operations and financial results. Therefore, Centuri meets the criteria to be reported as discontinued operations in accordance with U.S. GAAP. The results of discontinued operations are aggregated and presented separately in the Condensed Consolidated Statements of Income and Condensed Consolidated Statements of Cash Flows for all periods presented. Assets and liabilities of the discontinued operations are aggregated and reported separately on the Condensed Consolidated Balance Sheets as of December 31, 2024. Unless otherwise noted, the financial disclosures and related information provided herein relate to our continuing operations, which exclude our former Utility Infrastructure Services segment, and we have recast prior period amounts to reflect discontinued operations.

These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto of Southwest Gas and the Company included in our 2024 Annual Report on Form 10-K for the fiscal year ended December 31, 2024.

Other Property and Investments. Other property and investments on Southwest Gas’ and the Company’s Condensed Consolidated Balance Sheets includes:


(Thousands of dollars)	September 30, 2025		December 31, 2024
Net cash surrender value of COLI policies	$	161,717	$	155,199
Other property	4,418		4,479
Total Southwest Gas Corporation	166,135		159,678


Other property and investments	6,359		5,770
Total Southwest Gas Holdings, Inc.	$	172,494	$	165,448

Prepaid and other current assets. Prepaid and other current assets for the Company and Southwest Gas include, among other things, $82.7 million and $32.4 million related to a regulatory asset associated with the Arizona decoupling mechanism as of September 30, 2025 and December 31, 2024, respectively.

Other Income (Deductions). The following table provides the composition of significant items included in Other income (deductions) in Southwest Gas’ and the Company’s Condensed Consolidated Statements of Income:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Southwest Gas Corporation:
Change in COLI policies	$	2,700	$	3,200	$	6,500	$	7,800
Interest income	5,688		8,736		17,315		27,649
Equity AFUDC	1,501		1,874		4,412		5,548
Other components of net periodic benefit cost	4,369		4,131		13,106		12,392
Miscellaneous income and (expense)	(981)		(1,276)		(948)		(4,413)
Southwest Gas Corporation - total other income (deductions)	13,277		16,665		40,385		48,976
Southwest Gas Holdings, Inc.:

Corporate and administrative	2,090		(66)		2,244		(58)
Southwest Gas Holdings, Inc. – total other income (deductions)	$	15,367	$	16,599	$	42,629	$	48,918

Interest income primarily relates to Southwest Gas’ regulatory asset balances, including its deferred purchased gas cost mechanisms. Interest income is earned on asset balances and interest expense is incurred on liability balances. Corporate and administrative costs are those incurred directly by the parent entity, Southwest Gas Holdings. Refer also to Note 5 – Components of Net Periodic Benefit Cost for details regarding Other components of net periodic benefit cost.

EPS. Basic EPS in each period of this report were calculated by dividing net income attributable to the Company by the weighted-average number of shares during those periods. Diluted EPS includes additional weighted-average common stock equivalents (performance stock units and restricted stock units). Unless otherwise noted, the term EPS refers to Basic EPS. A reconciliation of the denominator used in Basic and Diluted EPS calculations is shown in the following table:


	Three Months Ended September 30,		Nine Months Ended September 30,
(In thousands)	2025	2024	2025	2024
Weighted average basic shares	72,209	71,880	72,104	71,816
Effect of dilutive securities:
Restricted stock units (1)(2)	196	206	161	178
Weighted average diluted shares	72,405	72,086	72,265	71,994

(1) The number of securities included 161,000 and 165,000 performance stock units during the three months ended September 30, 2025 and September 30, 2024. During the nine months ended September 30, 2025 and September 30, 2024, respectively, the number of securities included 136,000 and 148,000 performance stock units, the total of which was derived by assuming that target performance will be achieved during the relevant performance period.

(2) The number of anti-dilutive restricted stock units excluded from the calculation of diluted shares from continuing operations during the three months ended September 30, 2024 is 206,000 and from discontinued operations during the nine months ended September 30, 2024 is 178,000, respectively.

Income Taxes. The Company’s effective tax rate was (23.8)% for the three months ended September 30, 2025, compared to 46.0% for the corresponding period in 2024, primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and COLI. The Company’s effective tax rate was 17.9% for the nine months ended September 30, 2025, compared to 12.0% for the corresponding period in 2024, primarily due to pre-tax income differences, amortization of excess deferred income taxes, and COLI.

Southwest Gas’ effective tax rate was (8.3)% for the three months ended September 30, 2025, compared to 113.0% for the corresponding period in 2024, primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and COLI. Southwest Gas’ effective tax rate was 18.4% for the nine months ended September 30, 2025, compared to 14.2% in the corresponding period in 2024 primarily due to pre-tax income differences, the amortization of excess accumulated deferred income taxes, and COLI.

On July 4, 2025, the OBBBA was signed into law, which makes permanent many of the tax provisions enacted in 2017 as part of the Tax Cuts and Jobs Act that were set to expire at the end of 2025. In addition, the OBBBA makes changes to certain U.S. corporate tax provisions, but many are generally not effective until 2026. The Company and Southwest Gas have determined that the new legislation does not materially impact the results of operations.

Recent Accounting Standards Updates.

Recently issued accounting pronouncements that will be effective in 2025 and thereafter:

In December 2023, the FASB issued ASU 2023-09 “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” The update, among other amendments, provides for enhanced disclosures primarily related to changes in the effective income tax rate reconciliation and information regarding income taxes paid. The update is effective for annual periods beginning after December 15, 2024. Management plans to adopt ASU 2023-09 beginning with the fourth quarter of fiscal 2025 and utilize the retrospective application. The adoption of this ASU is not expected to have a material impact the Company’s and Southwest Gas’ disclosures.

In November 2024, the FASB issued ASU 2024-03 “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” The update requires disclosure of disaggregated information about certain income statement expense line items in the notes to the financial statements. The update is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027; early adoption is permitted. The update should be applied prospectively; however, retrospective application is also permitted. Management is evaluating the impacts this update might have on the Company’s and Southwest Gas’ disclosures.

In July 2025, the FASB issued ASU 2025-05 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets.” The amendments in this update provide a practical expedient permitting an entity to assume that conditions at the balance sheet date remain unchanged over the life of the asset when estimating expected credit losses for current accounts receivable and current contract assets. The update is effective for annual periods beginning after December 15, 2025; early adoption is permitted. Management plans to adopt ASU 2025-05 beginning with the fourth quarter of fiscal 2025 and utilize the practical expedient provided therein. The adoption of this ASU is not expected to have a material impact on the Company’s or Southwest Gas’ financial position or results of operations.

In September 2025, the FASB issued ASU 2025-06 “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software.” The amendments in this update improve the operability of the guidance by removing all references to software development project stages so that the guidance is neutral to different software development methods. This update is effective for annual periods beginning after December 15, 2027, including interim periods within those fiscal years; early adoption is permitted. Management is evaluating the impacts this update might have on the Company’s and Southwest Gas’ consolidated financial statements.

Segment Information (Tables)

9 Months Ended

Sep. 30, 2025

Segment Reporting [Abstract]

Schedule of Segment Reporting Information

The financial information pertaining to the Natural Gas Distribution segment is as follows:


	Three Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	273,985	$	—	$	273,985
Alternative revenue program and other revenues	42,926		—		42,926
Total segment revenue	316,911		—		316,911
Less:
Net cost of gas sold	42,685		—		42,685
Operations and maintenance	133,808		969		134,777
Other segment items (1)	135,320		757		136,077
Income (loss) from continuing operations before income taxes	5,098		(1,726)		3,372
Income tax benefit	(422)		(381)		(803)
Income (loss) from continuing operations	$	5,520	$	(1,345)	4,175
Income from discontinued operations, net of taxes					263,784
Net income					267,959
Net (loss) attributable to noncontrolling interests					(2,517)
Net income attributable to Southwest Gas Holdings, Inc.					$	270,476
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Three Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	5,688	$	—	$	5,688
Interest expense	$	46,156	$	2,847	$	49,003
Depreciation and amortization	$	79,073	$	—	$	79,073
Segment assets	$	9,725,477	$	603,102	$	10,328,579
Capital expenditures	$	207,894	$	—	$	207,894


	Three Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	321,391	$	—	$	321,391
Alternative revenue program and other revenues	37,740		—		37,740
Total segment revenue	359,131		—		359,131
Less:
Net cost of gas sold	111,712		—		111,712
Operations and maintenance	129,736		1,125		130,861
Other segment items (1)	122,083		11,560		133,643
Loss from continuing operations before income taxes	(4,400)		(12,685)		(17,085)
Income tax benefit	(4,972)		(2,886)		(7,858)
Income (loss) from continuing operations	$	572	$	(9,799)	(9,227)
Income from discontinued operations, net of taxes					11,890
Net income					2,663
Net income attributable to noncontrolling interests					2,374
Net income attributable to Southwest Gas Holdings, Inc.					$	289
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Three Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	8,736	$	—	$	8,736
Interest expense	$	42,312	$	11,494	$	53,806
Depreciation and amortization	$	74,153	$	—	$	74,153
Capital expenditures	$	252,373	$	—	$	252,373

	As of December 31, 2024
Segment assets	$	9,533,825	$	10,571	$	9,544,396


	Nine Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	1,399,603	$	—	$	1,399,603
Alternative revenue program and other revenues	60,042		—		60,042
Total segment revenue	1,459,645		—		1,459,645
Less:
Net cost of gas sold	429,398		—		429,398
Operations and maintenance	399,867		3,078		402,945
Other segment items (1)	407,221		19,019		426,240
Income (loss) from continuing operations before income taxes	223,159		(22,097)		201,062
Income tax expense (benefit)	41,020		(4,961)		36,059
Income (loss) from continuing operations	$	182,139	(17,136)		165,003
Income from discontinued operations, net of taxes					201,814
Net income					366,817
Net (loss) attributable to noncontrolling interests					(4,646)


Net income attributable to Southwest Gas Holdings, Inc.					$	371,463
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Nine Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	17,315	$	—	$	17,315
Interest expense	$	135,524	$	21,263	$	156,787
Depreciation and amortization	$	241,703	$	—	$	241,703
Segment assets	$	9,725,477	$	603,102	$	10,328,579
Capital expenditures	$	570,351	$	—	$	570,351


	Nine Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	1,892,245	$	—	$	1,892,245
Alternative revenue program and other revenues	29,912		—		29,912
Total segment revenue	1,922,157		—		1,922,157
Less:
Net cost of gas sold	984,188		—		984,188
Operations and maintenance	390,229		4,728		394,957
Other segment items (1)	356,696		33,915		390,611
Income (loss) from continuing operations before income taxes	191,044		(38,643)		152,401
Income tax expense (benefit)	27,053		(8,794)		18,259
Income (loss) from continuing operations	$	163,991	$	(29,849)	134,142
Net (loss) from discontinued operations, net of taxes					(23,707)
Net income					110,435
Net income attributable to noncontrolling interests					4,076
Net income attributable to Southwest Gas Holdings, Inc.					$	106,359
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Nine Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	27,649	$	—	$	27,649
Interest expense	$	118,595	$	33,857	$	152,452
Depreciation and amortization	$	220,663	$	—	$	220,663
Capital expenditures	$	643,720	$	—	$	643,720

	As of December 31, 2024
Segment assets	$	9,533,825	$	10,571	$	9,544,396

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2025

Accounting Policies [Abstract]

Schedule of Other Property and Investments

Other property and investments on Southwest Gas’ and the Company’s Condensed Consolidated Balance Sheets includes:


(Thousands of dollars)	September 30, 2025		December 31, 2024
Net cash surrender value of COLI policies	$	161,717	$	155,199
Other property	4,418		4,479
Total Southwest Gas Corporation	166,135		159,678


Other property and investments	6,359		5,770
Total Southwest Gas Holdings, Inc.	$	172,494	$	165,448

Schedule of Significant Items Included in Other Income (Deductions)

The following table provides the composition of significant items included in Other income (deductions) in Southwest Gas’ and the Company’s Condensed Consolidated Statements of Income:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Southwest Gas Corporation:
Change in COLI policies	$	2,700	$	3,200	$	6,500	$	7,800
Interest income	5,688		8,736		17,315		27,649
Equity AFUDC	1,501		1,874		4,412		5,548
Other components of net periodic benefit cost	4,369		4,131		13,106		12,392
Miscellaneous income and (expense)	(981)		(1,276)		(948)		(4,413)
Southwest Gas Corporation - total other income (deductions)	13,277		16,665		40,385		48,976
Southwest Gas Holdings, Inc.:

Corporate and administrative	2,090		(66)		2,244		(58)
Southwest Gas Holdings, Inc. – total other income (deductions)	$	15,367	$	16,599	$	42,629	$	48,918

Schedule of Earnings Per Share, Basic and Diluted

A reconciliation of the denominator used in Basic and Diluted EPS calculations is shown in the following table:


	Three Months Ended September 30,		Nine Months Ended September 30,
(In thousands)	2025	2024	2025	2024
Weighted average basic shares	72,209	71,880	72,104	71,816
Effect of dilutive securities:
Restricted stock units (1)(2)	196	206	161	178
Weighted average diluted shares	72,405	72,086	72,265	71,994

Centuri Separation - Schedule of Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total current assets classified as discontinued operations	$ 0	$ 601,384
Total noncurrent assets classified as discontinued operations	0	1,927,126
Total current liabilities classified as discontinued operations	7,919	382,892
Total noncurrent liabilities classified as discontinued operations	0	1,016,726
Discontinued Operations, Disposed of by Sale \| Centuri
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	0	49,019
Accounts receivable, net of allowances	0	519,610
Other current assets	0	32,755
Total current assets classified as discontinued operations	0	601,384
Other property and investments, net	0	1,025,700
Goodwill	0	770,046
Deferred income taxes	0	52,376
Deferred charges and other assets	0	79,004
Total noncurrent assets classified as discontinued operations	0	1,927,126
Current maturities of long-term debt	0	30,018
Accounts payable	0	140,889
Income tax payable	7,919	0
Other current liabilities	0	211,985
Total current liabilities classified as discontinued operations	7,919	382,892
Long-term debt, less current maturities	0	843,863
Other deferred credits	0	172,863
Total noncurrent liabilities classified as discontinued operations	$ 0	$ 1,016,726

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Total Regulated operations revenues	$ 316,911	$ 359,131	$ 1,459,645	$ 1,922,157
Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	273,985	321,391	1,399,603	1,892,245
Alternative revenue program revenues	40,064	34,341	52,568	17,978
Other revenues	2,862	3,399	7,474	11,934
Total Regulated operations revenues	316,911	359,131	1,459,645	1,922,157
Residential \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	168,742	189,156	969,225	1,283,945
Small commercial \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	50,564	70,708	252,953	387,793
Large commercial \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,758	20,569	56,394	87,895
Industrial/other \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,695	13,443	33,836	49,737
Transportation \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 28,226	$ 27,515	$ 87,195	$ 82,875

Components of Net Periodic Benefit Cost (Tables)

9 Months Ended

Sep. 30, 2025

Retirement Benefits [Abstract]

Schedule of Net Periodic Benefit Costs

The components of Southwest Gas' net periodic benefit cost for its QRP, SERP, and PBOP for the three and nine months ended September 30, 2025 and 2024 are presented in the following tables.


	Three Months Ended September 30,
	2025						2024
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	6,099	$	58	$	292	$	7,063	$	61	$	322
Interest cost	16,397		596		856		15,097		542		794
Expected return on plan assets	(22,582)		—		(623)		(21,953)		—		(565)
Amortization of prior service costs	—		—		44		—		—		44
Amortization of net actuarial loss (gain)	751		270		(78)		1,577		333		—
Net periodic benefit cost	$	665	$	924	$	491	$	1,784	$	936	$	595

	Nine Months Ended September 30,
	2025						2024
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	18,296	$	174	$	876	$	21,189	$	183	$	966
Interest cost	49,191		1,788		2,569		45,291		1,626		2,383
Expected return on plan assets	(67,745)		—		(1,871)		(65,859)		—		(1,695)
Amortization of prior service costs	—		—		132		—		—		132
Amortization of net actuarial loss (gain)	2,255		810		(235)		4,731		999		—
Net periodic benefit cost	$	1,997	$	2,772	$	1,471	$	5,352	$	2,808	$	1,786

Centuri Separation (Tables)

9 Months Ended

Sep. 30, 2025

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Net Proceeds from Sale of Stock

The following table presents the net proceeds received by the Company for the sale of Centuri common stock subsequent to the Centuri IPO:


Secondary Offering Information	Net Proceeds (in million) (1)
May 22, 2025 public offering and private placement	$	224.6

June 18, 2025 public offering	224.1
July 8, 2025 private placement	22.0
August 11, 2025 public offering and private placement	355.2

September 5, 2025 public offering	524.0
Total	$	1,349.9

(1) Net proceeds, net of transaction costs

Schedule of Disposal Groups, Including Discontinued Operations

The gain on deconsolidation as of August 11, 2025 is calculated as follows (in thousands):


Fair value of the retained investment in Centuri (1)	$	533,636
Net proceeds received from the August 11, 2025 public offering and private placement	355,220
Carrying value of noncontrolling interest attributable to Centuri prior to deconsolidation	460,897
Less: Carrying value of Centuri net assets prior to deconsolidation, including AOCI	(982,396)
Gain on deconsolidation of Centuri before income tax (2)	367,357
Income tax expense	88,566
Gain on deconsolidation of Centuri, net of tax	$	278,791

(1) Centuri’s quoted stock price is used for fair value measurement, which is classified as level 1 in the fair value hierarchy as of August 11, 2025.

(2) Includes $136.9 million gain on interest sold and $230.4 million gain on the investment retained.

The following table summarizes the components of assets and liabilities of discontinued operations on the Company’s Condensed Consolidated Balance Sheets at September 30, 2025 and December 31, 2024:


(Thousands of dollars)	September 30, 2025		December 31, 2024
Cash	$	—	$	49,019
Accounts receivable, net of allowances	—		519,610
Other current assets	—		32,755
Total current assets classified as discontinued operations	—		601,384

Other property and investments, net	—		1,025,700
Goodwill	—		770,046
Deferred income taxes	—		52,376
Deferred charges and other assets	—		79,004
Total noncurrent assets classified as discontinued operations	—		1,927,126

Current maturities of long-term debt	—		30,018
Accounts payable	—		140,889
Income tax payable (1)	7,919		—
Other current liabilities	—		211,985
Total current liabilities classified as discontinued operations	7,919		382,892

Long-term debt, less current maturities	—		843,863

Other deferred credits	—		172,863
Total noncurrent liabilities classified as discontinued operations	$	—	$	1,016,726
(1) Estimated tax payable related to Centuri disposition.

Summarized results from discontinued operations were as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Utility infrastructure services revenues	$	338,981	$	720,053	$	1,613,113	$	1,920,151
Utility infrastructure services expenses	(319,523)		(645,483)		(1,507,543)		(1,771,344)
Depreciation and amortization	(14,947)		(33,208)		(83,393)		(101,912)
Net interest deductions	(15,422)		(23,925)		(51,530)		(70,653)
Gain on deconsolidation	367,357		—		367,357		—
Loss on final disposition of retained interest	(9,688)		—		(9,688)		—
Other income (deductions), net	(9)		160		(136)		900

Income (loss) from discontinued operations before income taxes	346,749		17,597		328,180		(22,858)
Income tax expense	(82,965)		(5,707)		(126,366)		(849)
Net income (loss) from discontinued operations	263,784		11,890		201,814		(23,707)
Net income (loss) attributable to noncontrolling interest	(2,517)		2,374		(4,646)		4,076
Net income (loss) from discontinued operations attributable to Southwest Gas Holdings, Inc.	$	266,301	$	9,516	$	206,460	$	(27,783)

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-SubTopic 10
-Topic 360
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Subparagraph (b)(2)
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-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3A

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Subparagraph (b)(1)
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-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3A

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

Summary of Significant Accounting Policies - Schedule of Other Property and Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Property, Plant and Equipment [Line Items]
Other property and investments	$ 6,359	$ 5,770
Total	172,494	165,448
Southwest Gas Corporation
Property, Plant and Equipment [Line Items]
Net cash surrender value of COLI policies	161,717	155,199
Other property and investments	4,418	4,479
Total	$ 166,135	$ 159,678

Revenue (Tables)

9 Months Ended

Sep. 30, 2025

Revenue from Contract with Customer [Abstract]

Schedule of Revenue Disaggregated by Service Type and Contract Type

Southwest Gas’ operating revenues, but not its profits, are directly impacted by variability between comparative periods in the cost of natural gas procured for customers as such costs are incorporated in customer rates. When incorporated (for customers other than those taking transportation-only service), such costs are passed along to customers, generally dollar-for-dollar without markup. Southwest Gas’ revenues overall, reflected on the Condensed Consolidated Statements of Income of both the

Company and Southwest Gas, include revenue from contracts with customers, which is shown below, disaggregated by customer type, in addition to other categories of revenue:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Residential	$	168,742	$	189,156	$	969,225	$	1,283,945
Small commercial	50,564		70,708		252,953		387,793
Large commercial	16,758		20,569		56,394		87,895
Industrial/other	9,695		13,443		33,836		49,737
Transportation	28,226		27,515		87,195		82,875
Revenue from contracts with customers	273,985		321,391		1,399,603		1,892,245
Alternative revenue program revenues	40,064		34,341		52,568		17,978
Other revenues (1)	2,862		3,399		7,474		11,934
Total Regulated operations revenues	$	316,911	$	359,131	$	1,459,645	$	1,922,157

(1) Amounts include late fees and other miscellaneous revenues, and may also include the impact of certain regulatory mechanisms.

Segment Information

9 Months Ended

Sep. 30, 2025

Segment Reporting [Abstract]

Segment Information

Note 7 – Segment Information

The Company’s businesses were managed within two separate reportable segments until August 2025, our Natural Gas Distribution segment (Southwest Gas) and our Utility Infrastructure Services segment (Centuri). After August 2025, our business is solely comprised of our Natural Gas Distribution segment, see Note 6 - Centuri Separation. The results of the Utility Infrastructure Services segment are presented as discontinued operations in the Condensed Consolidated Statements of Income and, as such, have been excluded from continuing operations and segment results for all periods presented. Previously reported results for the Natural Gas Distribution segment were not impacted by the Centuri deconsolidation.

In order to reconcile to net income as disclosed in the Condensed Consolidated Statements of Income, an Other column is included below associated with certain unallocated expenses that represent the corporate and administrative activities associated with Southwest Gas Holdings, such as costs related to the Centuri separation and net interest deductions.

Segment information is presented in a similar manner to how the CODM, the Company’s CEO and President, reviews operating results in assessing performance and allocating resources. The CODM evaluates the performance of the reportable segment based on the segment’s net income (loss). The CODM considers budget-to-actual variances when making decisions about allocating capital and personnel to the segment. The CODM also uses net income (loss) to assess the return on assets of the segment including margin earned and in the compensation of certain employees.

The financial information pertaining to the Natural Gas Distribution segment is as follows:


	Three Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	273,985	$	—	$	273,985
Alternative revenue program and other revenues	42,926		—		42,926
Total segment revenue	316,911		—		316,911
Less:
Net cost of gas sold	42,685		—		42,685
Operations and maintenance	133,808		969		134,777
Other segment items (1)	135,320		757		136,077
Income (loss) from continuing operations before income taxes	5,098		(1,726)		3,372
Income tax benefit	(422)		(381)		(803)
Income (loss) from continuing operations	$	5,520	$	(1,345)	4,175
Income from discontinued operations, net of taxes					263,784
Net income					267,959
Net (loss) attributable to noncontrolling interests					(2,517)
Net income attributable to Southwest Gas Holdings, Inc.					$	270,476
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Three Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	5,688	$	—	$	5,688
Interest expense	$	46,156	$	2,847	$	49,003
Depreciation and amortization	$	79,073	$	—	$	79,073
Segment assets	$	9,725,477	$	603,102	$	10,328,579
Capital expenditures	$	207,894	$	—	$	207,894


	Three Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	321,391	$	—	$	321,391
Alternative revenue program and other revenues	37,740		—		37,740
Total segment revenue	359,131		—		359,131
Less:
Net cost of gas sold	111,712		—		111,712
Operations and maintenance	129,736		1,125		130,861
Other segment items (1)	122,083		11,560		133,643
Loss from continuing operations before income taxes	(4,400)		(12,685)		(17,085)
Income tax benefit	(4,972)		(2,886)		(7,858)
Income (loss) from continuing operations	$	572	$	(9,799)	(9,227)
Income from discontinued operations, net of taxes					11,890
Net income					2,663
Net income attributable to noncontrolling interests					2,374
Net income attributable to Southwest Gas Holdings, Inc.					$	289
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Three Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	8,736	$	—	$	8,736
Interest expense	$	42,312	$	11,494	$	53,806
Depreciation and amortization	$	74,153	$	—	$	74,153
Capital expenditures	$	252,373	$	—	$	252,373

	As of December 31, 2024
Segment assets	$	9,533,825	$	10,571	$	9,544,396


	Nine Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	1,399,603	$	—	$	1,399,603
Alternative revenue program and other revenues	60,042		—		60,042
Total segment revenue	1,459,645		—		1,459,645
Less:
Net cost of gas sold	429,398		—		429,398
Operations and maintenance	399,867		3,078		402,945
Other segment items (1)	407,221		19,019		426,240
Income (loss) from continuing operations before income taxes	223,159		(22,097)		201,062
Income tax expense (benefit)	41,020		(4,961)		36,059
Income (loss) from continuing operations	$	182,139	(17,136)		165,003
Income from discontinued operations, net of taxes					201,814
Net income					366,817
Net (loss) attributable to noncontrolling interests					(4,646)


Net income attributable to Southwest Gas Holdings, Inc.					$	371,463
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Nine Months Ended September 30, 2025
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	17,315	$	—	$	17,315
Interest expense	$	135,524	$	21,263	$	156,787
Depreciation and amortization	$	241,703	$	—	$	241,703
Segment assets	$	9,725,477	$	603,102	$	10,328,579
Capital expenditures	$	570,351	$	—	$	570,351


	Nine Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Revenue from contracts with customers	$	1,892,245	$	—	$	1,892,245
Alternative revenue program and other revenues	29,912		—		29,912
Total segment revenue	1,922,157		—		1,922,157
Less:
Net cost of gas sold	984,188		—		984,188
Operations and maintenance	390,229		4,728		394,957
Other segment items (1)	356,696		33,915		390,611
Income (loss) from continuing operations before income taxes	191,044		(38,643)		152,401
Income tax expense (benefit)	27,053		(8,794)		18,259
Income (loss) from continuing operations	$	163,991	$	(29,849)	134,142
Net (loss) from discontinued operations, net of taxes					(23,707)
Net income					110,435
Net income attributable to noncontrolling interests					4,076
Net income attributable to Southwest Gas Holdings, Inc.					$	106,359
(1) Other segment items includes: Depreciation and amortization, Taxes other than income taxes, Net interest deductions, and Other income (deductions).

Other segment disclosures	Nine Months Ended September 30, 2024
(Thousands of dollars)	Natural Gas Distribution		Other		Total
Interest income	$	27,649	$	—	$	27,649
Interest expense	$	118,595	$	33,857	$	152,452
Depreciation and amortization	$	220,663	$	—	$	220,663
Capital expenditures	$	643,720	$	—	$	643,720

	As of December 31, 2024
Segment assets	$	9,533,825	$	10,571	$	9,544,396

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2025
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations. The Company, a Delaware corporation, is a holding company owning all of the shares of common stock of Southwest Gas; and until April 22, 2024, all of the shares of common stock of Centuri. The Company’s common stock trades under the ticker symbol “SWX.” The Company’s businesses were managed within two separate reportable segments until August 2025, our Natural Gas Distribution segment (Southwest Gas) and our Utility Infrastructure Services segment (Centuri). After August 2025, our business is solely comprised of our Natural Gas Distribution segment (see Note 7 – Segment Information). Southwest Gas is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest Gas are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. While mechanisms exist in all states in which Southwest Gas operates, which decouple authorized operating cost recovery and profitability from the volume of natural gas sold, thereby also incentivizing energy conservation, results for the Natural Gas Distribution segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures.
Basis of Presentation	Basis of Presentation. The condensed consolidated financial statements of the Company and Southwest Gas included herein have been prepared pursuant to the rules and regulations of the SEC. The year-end 2024 condensed consolidated balance sheet data was derived from audited financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. The preparation of the condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. In the opinion of management, all adjustments, consisting of normal recurring items and estimates necessary for a fair statement of results for the interim periods, have been made. Discontinued Operations. On August 11, 2025, the Company completed a secondary public offering and a concurrent private placement transaction with Icahn investment entities. These transactions resulted in the sale of a combined total of 18,823,500 shares of Centuri common stock previously held by the Company (see Note 6 - Centuri Separation). Following the completion of these transactions, the Company no longer maintained a controlling financial interest in Centuri. Accordingly, Centuri’s assets, liabilities, and results of operations are no longer included in the Company’s consolidated financial statements. In addition, the sale of Centuri, which comprised the Company’s Utility Infrastructure Services segment, represents a strategic shift that has a significant impact on the Company’s operations and financial results. Therefore, Centuri meets the criteria to be reported as discontinued operations in accordance with U.S. GAAP. The results of discontinued operations are aggregated and presented separately in the Condensed Consolidated Statements of Income and Condensed Consolidated Statements of Cash Flows for all periods presented. Assets and liabilities of the discontinued operations are aggregated and reported separately on the Condensed Consolidated Balance Sheets as of December 31, 2024. Unless otherwise noted, the financial disclosures and related information provided herein relate to our continuing operations, which exclude our former Utility Infrastructure Services segment, and we have recast prior period amounts to reflect discontinued operations. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto of Southwest Gas and the Company included in our 2024 Annual Report on Form 10-K for the fiscal year ended December 31, 2024.
Earnings Per Share	EPS. Basic EPS in each period of this report were calculated by dividing net income attributable to the Company by the weighted-average number of shares during those periods. Diluted EPS includes additional weighted-average common stock equivalents (performance stock units and restricted stock units). Unless otherwise noted, the term EPS refers to Basic EPS.
Income Taxes	Income Taxes. The Company’s effective tax rate was (23.8)% for the three months ended September 30, 2025, compared to 46.0% for the corresponding period in 2024, primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and COLI. The Company’s effective tax rate was 17.9% for the nine months ended September 30, 2025, compared to 12.0% for the corresponding period in 2024, primarily due to pre-tax income differences, amortization of excess deferred income taxes, and COLI. Southwest Gas’ effective tax rate was (8.3)% for the three months ended September 30, 2025, compared to 113.0% for the corresponding period in 2024, primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and COLI. Southwest Gas’ effective tax rate was 18.4% for the nine months ended September 30, 2025, compared to 14.2% in the corresponding period in 2024 primarily due to pre-tax income differences, the amortization of excess accumulated deferred income taxes, and COLI. On July 4, 2025, the OBBBA was signed into law, which makes permanent many of the tax provisions enacted in 2017 as part of the Tax Cuts and Jobs Act that were set to expire at the end of 2025. In addition, the OBBBA makes changes to certain U.S. corporate tax provisions, but many are generally not effective until 2026. The Company and Southwest Gas have determined that the new legislation does not materially impact the results of operations.
Recent Accounting Standards Updates	Recent Accounting Standards Updates. Recently issued accounting pronouncements that will be effective in 2025 and thereafter: In December 2023, the FASB issued ASU 2023-09 “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” The update, among other amendments, provides for enhanced disclosures primarily related to changes in the effective income tax rate reconciliation and information regarding income taxes paid. The update is effective for annual periods beginning after December 15, 2024. Management plans to adopt ASU 2023-09 beginning with the fourth quarter of fiscal 2025 and utilize the retrospective application. The adoption of this ASU is not expected to have a material impact the Company’s and Southwest Gas’ disclosures. In November 2024, the FASB issued ASU 2024-03 “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” The update requires disclosure of disaggregated information about certain income statement expense line items in the notes to the financial statements. The update is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027; early adoption is permitted. The update should be applied prospectively; however, retrospective application is also permitted. Management is evaluating the impacts this update might have on the Company’s and Southwest Gas’ disclosures. In July 2025, the FASB issued ASU 2025-05 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets.” The amendments in this update provide a practical expedient permitting an entity to assume that conditions at the balance sheet date remain unchanged over the life of the asset when estimating expected credit losses for current accounts receivable and current contract assets. The update is effective for annual periods beginning after December 15, 2025; early adoption is permitted. Management plans to adopt ASU 2025-05 beginning with the fourth quarter of fiscal 2025 and utilize the practical expedient provided therein. The adoption of this ASU is not expected to have a material impact on the Company’s or Southwest Gas’ financial position or results of operations. In September 2025, the FASB issued ASU 2025-06 “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software.” The amendments in this update improve the operability of the guidance by removing all references to software development project stages so that the guidance is neutral to different software development methods. This update is effective for annual periods beginning after December 15, 2027, including interim periods within those fiscal years; early adoption is permitted. Management is evaluating the impacts this update might have on the Company’s and Southwest Gas’ consolidated financial statements.

- Definition

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.

+ References + Details

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Amortization of prior service cost, tax	$ 11	$ 11	$ 33	$ 33
Amortization of net actuarial loss, tax	226	458	678	1,375
Regulatory adjustment, tax	$ (153)	$ (347)	$ (457)	$ (1,043)

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2025	Dec. 31, 2024
Statement of Financial Position [Abstract]
Common stock, par (in USD per share)	$ 1	$ 1
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	72,180,889	71,782,756
Common stock, outstanding (in shares)	72,180,889	71,782,756

Revenue

9 Months Ended

Sep. 30, 2025

Revenue from Contract with Customer [Abstract]

Revenue

Note 3 – Revenue

Company and Southwest Gas, include revenue from contracts with customers, which is shown below, disaggregated by customer type, in addition to other categories of revenue:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Residential	$	168,742	$	189,156	$	969,225	$	1,283,945
Small commercial	50,564		70,708		252,953		387,793
Large commercial	16,758		20,569		56,394		87,895
Industrial/other	9,695		13,443		33,836		49,737
Transportation	28,226		27,515		87,195		82,875
Revenue from contracts with customers	273,985		321,391		1,399,603		1,892,245
Alternative revenue program revenues	40,064		34,341		52,568		17,978
Other revenues (1)	2,862		3,399		7,474		11,934
Total Regulated operations revenues	$	316,911	$	359,131	$	1,459,645	$	1,922,157

(1) Amounts include late fees and other miscellaneous revenues, and may also include the impact of certain regulatory mechanisms.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - Southwest - USD ($) $ in Thousands	Total	Southwest Gas Corporation	Common Stock	Common Stock Southwest Gas Corporation	Additional Paid-in Capital	Additional Paid-in Capital Southwest Gas Corporation	AOCI	AOCI Southwest Gas Corporation	Retained Earnings	Retained Earnings Southwest Gas Corporation
Beginning balance (in shares) at Dec. 31, 2023			71,564,000	47,482,000
Beginning balance at Dec. 31, 2023	$ 3,310,036	$ 3,183,615	$ 73,194	$ 49,112	$ 2,541,790	$ 2,156,577	$ (43,787)	$ (40,548)	$ 738,839	$ 1,018,474
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	87,737	135,825							87,737	135,825
Dividends declared to Southwest Gas Holdings, Inc.	(44,699)	(41,699)							(44,699)	(41,699)
Share-based compensation		(586)				(259)				(327)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	384	384					384	384
Ending balance (in shares) at Mar. 31, 2024			71,665,000	47,482,000
Ending balance at Mar. 31, 2024	3,356,241	3,277,539	$ 73,295	$ 49,112	2,547,485	2,156,318	(46,222)	(40,164)	781,683	1,112,273
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18,333	27,594							18,333	27,594
Dividends declared to Southwest Gas Holdings, Inc.	(44,649)	(52,101)							(44,649)	(52,101)
Share-based compensation		4,117				4,217				(100)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	386	386					386	386
Ending balance (in shares) at Jun. 30, 2024			71,709,000	47,482,000
Ending balance at Jun. 30, 2024	3,666,964	3,257,535	$ 73,339	$ 49,112	2,709,674	2,160,535	(45,615)	(39,778)	755,367	1,087,666
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	289	572							289	572
Dividends declared to Southwest Gas Holdings, Inc.	(44,716)	(44,500)							(44,716)	(44,500)
Share-based compensation		1,571				1,661				(90)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	384	384					384	384
Ending balance (in shares) at Sep. 30, 2024			71,740,000	47,482,000
Ending balance at Sep. 30, 2024	$ 3,632,250	3,215,562	$ 73,370	$ 49,112	2,714,958	2,162,196	(43,875)	(39,394)	710,940	1,043,648
Beginning balance (in shares) at Dec. 31, 2024	71,782,756		71,783,000	47,482,000
Beginning balance at Dec. 31, 2024	$ 3,681,422	3,271,862	$ 73,413	$ 49,112	2,721,343	2,165,002	(49,218)	(38,401)	758,649	1,096,149
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	113,870	142,942							113,870	142,942
Dividends declared to Southwest Gas Holdings, Inc.	(45,066)								(45,066)
Share-based compensation		1,800				2,116				(316)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	268	268					268	268
Ending balance (in shares) at Mar. 31, 2025			71,911,000	47,482,000
Ending balance at Mar. 31, 2025	3,751,445	3,416,872	$ 73,541	$ 49,112	2,726,758	2,167,118	(48,866)	(38,133)	827,453	1,238,775
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(12,883)	33,677							(12,883)	33,677
Dividends declared to Southwest Gas Holdings, Inc.	(44,847)	(44,609)							(44,847)	(44,609)
Share-based compensation		2,166				2,249				(83)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	267	267					267	267
Ending balance (in shares) at Jun. 30, 2025			71,978,000	47,482,000
Ending balance at Jun. 30, 2025	4,115,805	3,408,373	$ 73,608	$ 49,112	2,872,681	2,169,367	(41,355)	(37,866)	769,723	1,227,760
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	270,476	5,520							270,476	5,520
Dividends declared to Southwest Gas Holdings, Inc.	(45,016)								(45,016)
Share-based compensation		2,301				2,385				(84)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	$ 269	269					269	269
Ending balance (in shares) at Sep. 30, 2025	72,180,889		72,181,000	47,482,000
Ending balance at Sep. 30, 2025	$ 3,928,679	$ 3,416,463	$ 73,811	$ 49,112	$ 2,893,066	$ 2,171,752	$ (37,597)	$ (37,597)	$ 999,399	$ 1,233,196

- Definition

Amount of equity (deficit) attributable to parent and noncontrolling interest. Excludes temporary equity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(i))
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-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
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-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Section 65
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-Subparagraph (e)
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-URI https://asc.fasb.org/1943274/2147479343/105-10-65-9

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Section 65
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-Subparagraph (d)(2)
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
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Reference 8: http://www.xbrl.org/2003/role/exampleRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Regulated operations plant:
Gas plant	$ 11,289,621	$ 10,844,895
Less: accumulated depreciation	(3,025,110)	(2,914,457)
Construction work in progress	231,095	178,647
Net regulated operations plant	8,495,606	8,109,085
Other property and investments, net	172,494	165,448
Current assets:
Cash and cash equivalents	778,631	314,770
Accounts receivable, net of allowances	110,575	203,012
Accrued utility revenue	51,700	96,600
Deferred purchased gas costs	99	13,807
Materials, supplies, and gas inventories	91,154	93,755
Prepaid and other current assets	211,334	141,017
Current assets classified as discontinued operations	0	601,384
Total current assets	1,243,493	1,464,345
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	405,831	395,747
Noncurrent assets classified as discontinued operations	0	1,927,126
Total noncurrent assets	416,986	2,334,028
Total assets	10,328,579	12,072,906
Capitalization:
Common stock, $1 par (authorized - 120,000,000 shares; issued and outstanding - 72,180,889 and 71,782,756 shares)	73,811	73,413
Additional paid-in capital	2,893,066	2,721,343
Accumulated other comprehensive loss, net	(37,597)	(49,218)
Retained earnings	999,399	758,649
Total equity attributable to Southwest Gas Holdings, Inc. stockholders	3,928,679	3,504,187
Noncontrolling interest	0	177,235
Total equity	3,928,679	3,681,422
Redeemable noncontrolling interest	0	7,660
Long-term debt, less current maturities	3,507,120	3,504,477
Total capitalization	7,435,799	7,193,559
Current liabilities:
Short-term debt	0	680,000
Accounts payable	118,932	190,918
Customer deposits	67,026	63,876
Accrued general taxes	58,594	59,353
Accrued interest	38,503	35,668
Deferred purchased gas costs	356,458	255,398
Dividends declared	44,752	44,505
Other current liabilities	112,519	119,357
Current liabilities classified as discontinued operations	7,919	382,892
Total current liabilities	804,703	1,831,967
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	905,604	857,982
Accumulated removal costs	490,000	472,000
Other deferred credits and other long-term liabilities	692,473	700,672
Noncurrent liabilities classified as discontinued operations	0	1,016,726
Total deferred income taxes and other credits	2,088,077	3,047,380
Total capitalization and liabilities	$ 10,328,579	$ 12,072,906

Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Total operating revenues	$ 316,911	$ 359,131	$ 1,459,645	$ 1,922,157
Net cost of gas sold	42,685	111,712	429,398	984,188
Operations and maintenance	134,777	130,861	402,945	394,957
Other segment items	136,077	133,643	426,240	390,611
Income (loss) from continuing operations before income taxes	3,372	(17,085)	201,062	152,401
Income tax expense (benefit)	(803)	(7,858)	36,059	18,259
Income (loss) from continuing operations	4,175	(9,227)	165,003	134,142
Income (loss) from discontinued operations, net of income tax	263,784	11,890	201,814	(23,707)
Net income	267,959	2,663	366,817	110,435
Net income (loss) attributable to noncontrolling interests	(2,517)	2,374	(4,646)	4,076
Net income	270,476	289	371,463	106,359
Interest income	5,688	8,736	17,315	27,649
Interest expense	49,003	53,806	156,787	152,452
Depreciation and amortization	79,073	74,153	241,703	220,663
Capital expenditures	207,894	252,373	570,351	643,720
Segment assets	10,328,579		10,328,579		$ 12,072,906
Continuing Operations
Segment Reporting Information [Line Items]
Segment assets					9,544,396
Operating Segments
Segment Reporting Information [Line Items]
Revenue from contracts with customers	273,985	321,391	1,399,603	1,892,245
Alternative revenue program and other revenues	42,926	37,740	60,042	29,912
Other
Segment Reporting Information [Line Items]
Net cost of gas sold	0	0	0	0
Operations and maintenance	969	1,125	3,078	4,728
Other segment items	757	11,560	19,019	33,915
Income (loss) from continuing operations before income taxes	(1,726)	(12,685)	(22,097)	(38,643)
Income tax expense (benefit)	(381)	(2,886)	(4,961)	(8,794)
Income (loss) from continuing operations	(1,345)	(9,799)	(17,136)	(29,849)
Interest income	0	0	0	0
Interest expense	2,847	11,494	21,263	33,857
Depreciation and amortization	0	0	0	0
Capital expenditures	0	0	0	0
Segment assets	603,102		603,102
Other \| Continuing Operations
Segment Reporting Information [Line Items]
Segment assets					10,571
Natural Gas Distribution \| Operating Segments
Segment Reporting Information [Line Items]
Revenue from contracts with customers	273,985	321,391	1,399,603	1,892,245
Alternative revenue program and other revenues	42,926	37,740	60,042	29,912
Total operating revenues	316,911	359,131	1,459,645	1,922,157
Net cost of gas sold	42,685	111,712	429,398	984,188
Operations and maintenance	133,808	129,736	399,867	390,229
Other segment items	135,320	122,083	407,221	356,696
Income (loss) from continuing operations before income taxes	5,098	(4,400)	223,159	191,044
Income tax expense (benefit)	(422)	(4,972)	41,020	27,053
Income (loss) from continuing operations	5,520	572	182,139	163,991
Interest income	5,688	8,736	17,315	27,649
Interest expense	46,156	42,312	135,524	118,595
Depreciation and amortization	79,073	74,153	241,703	220,663
Capital expenditures	207,894	$ 252,373	570,351	$ 643,720
Segment assets	$ 9,725,477		$ 9,725,477
Natural Gas Distribution \| Operating Segments \| Continuing Operations
Segment Reporting Information [Line Items]
Segment assets					$ 9,533,825

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Net income	$ 267,959	$ 2,663	$ 366,817	$ 110,435
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11, $11, $33 and $33, respectively	33	33	99	99
Amortization of net actuarial loss, net of tax of $226, $458, $678 and $1,375, respectively	717	1,452	2,152	4,355
Regulatory adjustment, net of tax of ($153), ($347), ($457) and ($1,043), respectively	(481)	(1,101)	(1,447)	(3,300)
Net defined benefit pension plans, net of tax	269	384	804	1,154
Total other comprehensive income (loss), net of tax	(1,393)	2,059	5,957	(1,142)
Comprehensive income	266,566	4,722	372,774	109,293
Southwest Gas Corporation
Net income	5,520	572	182,139	163,991
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11, $11, $33 and $33, respectively	33	33	99	99
Amortization of net actuarial loss, net of tax of $226, $458, $678 and $1,375, respectively	717	1,452	2,152	4,355
Regulatory adjustment, net of tax of ($153), ($347), ($457) and ($1,043), respectively	(481)	(1,101)	(1,447)	(3,300)
Net defined benefit pension plans, net of tax	269	384	804	1,154
Total other comprehensive income (loss), net of tax	269	384	804	1,154
Comprehensive income	$ 5,789	$ 956	$ 182,943	$ 165,145

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share (in USD per share)	$ 0.62	$ 0.62	$ 0.62	$ 0.62	$ 0.62	$ 0.62

Centuri Separation

9 Months Ended

Sep. 30, 2025

Discontinued Operations and Disposal Groups [Abstract]

Centuri Separation

Note 6 - Centuri Separation

In April 2024, the Company and Centuri announced the completion of the Centuri IPO, prior to which Centuri was a wholly owned subsidiary of the Company. Immediately upon the completion of the Centuri IPO, the Company continued to own approximately 81% of the outstanding shares of common stock of Centuri.

In May 2025, the Company completed a secondary public offering of 10,350,000 shares of Centuri’s common stock owned by the Company (inclusive of 1,350,000 shares related to the exercise of the overallotment option) at a price of $17.50 per share. In addition, the Company sold 2,857,142 shares at a price equal to the public offering price to the Icahn investment entities in a concurrent private placement. The net proceeds to the Company from this public offering and concurrent private placement, after deducting underwriting discounts and commissions of $6.6 million and other fees, were approximately $224.6 million.

In June 2025, the Company completed an additional secondary public offering of 11,212,500 shares of Centuri’s common stock owned by the Company (inclusive of 1,462,500 shares related to the exercise of the overallotment option) at a price of $20.75 per share. The net proceeds to the Company from the public offering, after deducting underwriting discounts and commissions of $8.6 million and other fees, were approximately $224.1 million. In addition, in July 2025 the Company closed the concurrent private placement sale of an additional 1,060,240 shares at a price equal to the June 2025 Centuri public offering price, with

Icahn investment entities. The net proceeds to the Company from this concurrent private placement were approximately $22.0 million. After completion of the June 2025 public offering and July 2025 private placement, the Company owned approximately 52.1% of the then-outstanding Centuri common stock.

On August 11, 2025, the Company completed an additional secondary public offering and concurrent private placement sale with Icahn investment entities for a combined total of 18,823,500 shares of Centuri common stock owned by the Company at a price of $19.50 per share. The net proceeds to the Company, after deducting underwriting discounts and commissions of $11.8 million and other fees, were approximately $355.2 million. The Company used the proceeds for the repayment of outstanding indebtedness, the third quarter dividends to stockholders, and will use the remainder for general corporate purposes (see Note 4 – Debt). After completion of the offering and concurrent private placement, the Company owned approximately 30.9% of the then-outstanding Centuri common stock, and, therefore, no longer had a controlling financial interest in Centuri. As a result, the Company met the requirements for the deconsolidation of Centuri. In addition, the sale of Centuri, which comprised the Company’s Utility Infrastructure Services segment, represents a strategic shift that has a significant impact on the Company’s operations and financial results. Therefore, the sale meets the criteria to be reported as discontinued operations in accordance with U.S. GAAP. Accordingly, the historical financial results of Centuri, for all periods presented, are reflected in the Condensed Consolidated Financial Statements as discontinued operations. On August 11, 2025, following the deconsolidation of Centuri, the Company remeasured its retained 30.9% ownership interest at fair value. This remeasurement resulted in a gain of $230.4 million, which was included in the total gain recognized upon deconsolidation further described below. Subsequent to this date, the Company elected to continue measuring its retained interest, accounted for under the equity method, at fair value through the date of final disposition on September 5, 2025. Upon final disposition, the Company recognized a loss of $9.7 million. After considering the initial fair value adjustment, the Company recorded a net gain of $220.7 million related to the disposition on its retained interest in Centuri.

On September 5, 2025, the Company completed a final additional secondary public offering of 27,362,210 shares of Centuri common stock owned by the Company at a price of $19.18 per share. After completion of the offering, the Company no longer owns any shares of Centuri common stock and no longer has governance rights afforded to it under the Separation Agreement, including the right to nominate any of Centuri’s directors and any remaining consent rights over certain of Centuri’s corporate actions. The net proceeds to the Company from the public offering, after deducting other fees of approximately $900,000, were approximately $524.0 million.

Centuri did not receive any of the proceeds from the series of public offerings or private placements subsequent to the Centuri IPO. The Company expects to use the proceeds for general corporate purposes including support for future capital investments at Southwest Gas as well as the potential 2028 expansion of Great Basin, and future dividend payments to stockholders that would otherwise have been funded by Southwest Gas.

The following table presents the net proceeds received by the Company for the sale of Centuri common stock subsequent to the Centuri IPO:


Secondary Offering Information	Net Proceeds (in million) (1)
May 22, 2025 public offering and private placement	$	224.6

June 18, 2025 public offering	224.1
July 8, 2025 private placement	22.0
August 11, 2025 public offering and private placement	355.2

September 5, 2025 public offering	524.0
Total	$	1,349.9

(1) Net proceeds, net of transaction costs

Discontinued Operations

The gain on deconsolidation as of August 11, 2025 is calculated as follows (in thousands):


Fair value of the retained investment in Centuri (1)	$	533,636
Net proceeds received from the August 11, 2025 public offering and private placement	355,220
Carrying value of noncontrolling interest attributable to Centuri prior to deconsolidation	460,897
Less: Carrying value of Centuri net assets prior to deconsolidation, including AOCI	(982,396)
Gain on deconsolidation of Centuri before income tax (2)	367,357
Income tax expense	88,566
Gain on deconsolidation of Centuri, net of tax	$	278,791

(1) Centuri’s quoted stock price is used for fair value measurement, which is classified as level 1 in the fair value hierarchy as of August 11, 2025.

(2) Includes $136.9 million gain on interest sold and $230.4 million gain on the investment retained.


(Thousands of dollars)	September 30, 2025		December 31, 2024
Cash	$	—	$	49,019
Accounts receivable, net of allowances	—		519,610
Other current assets	—		32,755
Total current assets classified as discontinued operations	—		601,384

Other property and investments, net	—		1,025,700
Goodwill	—		770,046
Deferred income taxes	—		52,376
Deferred charges and other assets	—		79,004
Total noncurrent assets classified as discontinued operations	—		1,927,126

Current maturities of long-term debt	—		30,018
Accounts payable	—		140,889
Income tax payable (1)	7,919		—
Other current liabilities	—		211,985
Total current liabilities classified as discontinued operations	7,919		382,892

Long-term debt, less current maturities	—		843,863

Other deferred credits	—		172,863
Total noncurrent liabilities classified as discontinued operations	$	—	$	1,016,726
(1) Estimated tax payable related to Centuri disposition.

Summarized results from discontinued operations were as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
(Thousands of dollars)	2025		2024		2025		2024
Utility infrastructure services revenues	$	338,981	$	720,053	$	1,613,113	$	1,920,151
Utility infrastructure services expenses	(319,523)		(645,483)		(1,507,543)		(1,771,344)
Depreciation and amortization	(14,947)		(33,208)		(83,393)		(101,912)
Net interest deductions	(15,422)		(23,925)		(51,530)		(70,653)
Gain on deconsolidation	367,357		—		367,357		—
Loss on final disposition of retained interest	(9,688)		—		(9,688)		—
Other income (deductions), net	(9)		160		(136)		900

Income (loss) from discontinued operations before income taxes	346,749		17,597		328,180		(22,858)
Income tax expense	(82,965)		(5,707)		(126,366)		(849)
Net income (loss) from discontinued operations	263,784		11,890		201,814		(23,707)
Net income (loss) attributable to noncontrolling interest	(2,517)		2,374		(4,646)		4,076
Net income (loss) from discontinued operations attributable to Southwest Gas Holdings, Inc.	$	266,301	$	9,516	$	206,460	$	(27,783)

During the second quarter 2025, following the May 2025 sale of Centuri common stock, the Company was no longer eligible to include Centuri in its consolidated federal and certain state income tax returns (tax deconsolidation) and the Company’s tax-free spin protection plan expired. As such, the Company could no longer assert the ability to complete a tax-free disposition of its investment in Centuri. This event required the Company to recognize a previously unrecorded deferred tax liability related to the outside basis of its investment in Centuri. The Company recognized tax expense of $14.4 million and $66.8 million for the three-month and nine-month periods ended September 30, 2025, respectively, related to the recognition of outside basis differences. Following the sale of the Company’s remaining shares of Centuri common stock in September 2025, the Company was no longer eligible to include Centuri in its remaining state income tax returns.

The Company recorded a tax benefit of $15.7 million and $22.7 million for the three-month and nine-month periods ended September 30, 2025, respectively, related to deferred tax assets. These benefits reflect state net operating losses that are now expected to be utilized in connection with the disposition of Centuri shares. The combined effect of these items resulted in a net tax benefit of $1.3 million for the three-month period ended September 30, 2025, and a net tax expense of $44.1 million for the nine-month period ended September 30, 2025.

On February 24, 2025, the Company entered into a Tax Assets Agreement with Centuri. The Tax Assets Agreement addresses the Company’s arrangements with Centuri with respect to certain Tax Assets that each company will retain following any deconsolidation for U.S. federal and relevant state income tax laws. Under the terms of the Tax Assets Agreement, the Company contributed $56.4 million of Tax Assets to Centuri, which were treated as a deemed capital contribution. This amount is subject to change and will be finalized upon the filing of the 2024 and 2025 final consolidated or combined federal and state income tax returns. Any future changes to the Tax Assets contributed to Centuri will be recorded in discontinued operations.

Centuri Separation - Schedule of Net Income from Discontinued Operations (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 11, 2025	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disposal Group, Including Discontinued Operation, Operating Expenses [Abstract]
Net income (loss) from discontinued operations		$ 263,784	$ 11,890	$ 201,814	$ (23,707)
Discontinued Operations, Disposed of by Sale \| Centuri
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Utility infrastructure services revenues		338,981	720,053	1,613,113	1,920,151
Disposal Group, Including Discontinued Operation, Operating Expenses [Abstract]
Utility infrastructure services expenses		(319,523)	(645,483)	(1,507,543)	(1,771,344)
Depreciation and amortization		(14,947)	(33,208)	(83,393)	(101,912)
Net interest deductions		(15,422)	(23,925)	(51,530)	(70,653)
Gain on deconsolidation	$ 367,357	367,357	0	367,357	0
Loss on final disposition of retained interest		(9,688)	0	(9,688)	0
Other income (deductions), net		(9)	160	(136)	900
Income (loss) from discontinued operations before income taxes		346,749	17,597	328,180	(22,858)
Income tax expense		(82,965)	(5,707)	(126,366)	(849)
Net income (loss) from discontinued operations		263,784	11,890	201,814	(23,707)
Net income (loss) attributable to noncontrolling interest		(2,517)	2,374	(4,646)	4,076
Income (loss) from discontinued operations, net of income tax		$ 266,301	$ 9,516	$ 206,460	$ (27,783)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands

9 Months Ended

Sep. 30, 2025

Sep. 30, 2024

CASH FLOW FROM OPERATING ACTIVITIES:

Net income

$ 366,817

$ 110,435

Less: Income (loss) from discontinued operations, net of income tax

201,814

(23,707)

Income from continuing operations, net of income tax

165,003

134,142

Adjustments to reconcile net income to net cash provided by operating activities:

Depreciation and amortization

241,703

220,663

Deferred income taxes

48,141

38,601

Gains on sale of property and equipment

(1,604)

Changes in undistributed stock compensation

9,992

8,021

Equity AFUDC

(4,412)

(5,548)

Changes in current assets and liabilities:

Accounts receivable, net of allowances

92,437

137,655

Accrued utility revenue

44,900

45,200

Deferred purchased gas costs

114,768

678,478

Accounts payable

(65,842)

(103,869)

Accrued taxes

(364)

8,193

Other current assets and liabilities

(73,000)

(37,508)

Changes in deferred charges and other assets

(42,386)

(37,054)

Changes in other liabilities and deferred credits

(20,200)

(24,496)

Net cash provided by operating activities of continuing operations

509,136

1,062,478

Net cash provided (used) by operating activities of discontinued operations

(34,628)

91,858

Net cash provided by operating activities

474,508

1,154,336

CASH FLOW FROM INVESTING ACTIVITIES:

Capital expenditures and property additions

(570,351)

(643,720)

Proceeds from the sale of property

5,306

21,377

Changes in customer advances

3,246

(4,804)

Other

307

(884)

Net cash used in investing activities of continuing operations

(561,492)

(628,031)

Net cash provided (used) in investing activities of discontinued operations

^[1]

776,678

(59,291)

Net cash provided (used) in investing activities

215,186

(687,322)

CASH FLOW FROM FINANCING ACTIVITIES:

Issuance of common stock, net

17,682

6,681

Dividends paid

(133,855)

(133,285)

Change in short-term portion of credit facility

(130,000)

34,500

Repayment of short-term debt

(550,000)

Withholding remittance - share-based compensation

(2,613)

(1,800)

Other, including principal payments on finance leases

(4,283)

(3,636)

Net cash used in financing activities of continuing operations

(803,069)

(97,540)

Net cash provided (used) in financing activities of discontinued operations

528,344

(19,225)

Net cash used in financing activities

(274,725)

(116,765)

Effects of currency translation in discontinued operations

(127)

(142)

Change in cash and cash equivalents, including discontinued operations

414,842

350,107

Cash and cash equivalents, including discontinued operations, at beginning of period

363,789

106,536

Cash and cash equivalents, including discontinued operations, at end of period

778,631

456,643

SUPPLEMENTAL INFORMATION:

Interest paid, net of amounts capitalized

192,076

204,135

Income taxes paid, net

29,237

8,108

Decrease of capital expenditures in Accounts payable or Other current liabilities

(9,986)

(28,087)

Centuri

CASH FLOW FROM FINANCING ACTIVITIES:

Change in cash and cash equivalents, including discontinued operations

49,000

Continuing Operations

SUPPLEMENTAL INFORMATION:

Interest paid, net of amounts capitalized

148,776

145,104

Income taxes paid, net

(2,259)

Decrease of capital expenditures in Accounts payable or Other current liabilities

(800)

(17,000)

Discontinued Operations

SUPPLEMENTAL INFORMATION:

Interest paid, net of amounts capitalized

43,300

59,031

Income taxes paid, net

29,237

10,367

Decrease of capital expenditures in Accounts payable or Other current liabilities

$ (9,186)

$ (11,087)

[1]	(1) Includes change in cash and cash equivalent of Centuri of $49 million.

Background and Organization (Details) - segment	1 Months Ended		8 Months Ended
Background and Organization (Details) - segment	Sep. 30, 2025	Aug. 31, 2025	Aug. 31, 2025	Aug. 01, 2025	Apr. 30, 2024
Significant Accounting Policies [Line Items]
Number of reportable segments	1	2	2
Centuri
Significant Accounting Policies [Line Items]
Ownership percentage by parent				52.10%	81.00%

Debt

9 Months Ended

Sep. 30, 2025

Debt Disclosure [Abstract]

Debt

Note 4 – Debt

Long-Term Debt

Long-term debt is recognized in the Company’s and Southwest Gas’ Condensed Consolidated Balance Sheets generally at the carrying value of the obligations outstanding. Details surrounding the fair value and individual carrying values of instruments are provided in the table that follows.


	September 30, 2025				December 31, 2024
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
(Thousands of dollars)
Southwest Gas Holdings, Inc. and Southwest Gas Corporation:
Southwest Gas long-term debt	$	3,532,500	$	3,236,584	$	3,532,500	$	3,121,449
Unamortized discount and debt issuance costs	(25,380)				(28,023)
Southwest Gas Holdings, Inc. and Southwest Gas Corporation total long-term debt (no current maturities)	$	3,507,120			$	3,504,477

Southwest Gas has a $400 million revolving credit facility that is scheduled to expire in August 2029. Southwest Gas designates $150 million of associated capacity as long-term debt and the remaining $250 million for working capital purposes. In June 2025, Southwest Gas amended this revolving credit agreement, which among other things, added a swingline loan sub-facility in an aggregate principal amount at any time outstanding not to exceed $30 million and added a one-week interest period option with an interest rate equal to Daily Simple SOFR plus 0.03839% plus the applicable margin. At September 30, 2025, the applicable margin is 1.125% for loans bearing interest with reference to SOFR and 0.125% for loans bearing interest with reference to the alternative base rate. At September 30, 2025, no borrowings were outstanding on the long-term portion (including under the commercial paper program), nor under the short-term portion of the facility.

Short-Term Debt

In June 2025, Southwest Gas Holdings entered into a new $300 million revolving credit agreement that matures in August 2029, replacing Southwest Gas Holdings’ existing $300 million credit facility that was set to expire in December 2026. At September 30, 2025, the applicable margin is 1.25% for loans bearing interest to SOFR and 0.25% for loans bearing interest with reference to the alternative base. Southwest Gas Holdings has a one-week interest period option with an interest rate equal to Daily Simple SOFR plus 0.03839% plus the applicable margin. Southwest Gas Holdings is also required to pay a commitment fee on the unfunded portion of the commitments which ranges from 0.075% to 0.200%. The revolving credit agreement also contains a swingline loan sub-facility in an aggregate principal amount at any time outstanding not to exceed $30 million. At September 30, 2025, there were no borrowings outstanding under this credit facility.

In August 2024, Southwest Gas Holdings entered into a $550 million term loan that had been set to mature in July 2025. In June 2025, Southwest Gas Holdings entered into a second amended and restated term loan credit agreement, extending the maturity date of this agreement to June 2026 and excluding Centuri and its subsidiaries from certain material representations, covenants, and events of default. Prior to the execution of the amendment, Southwest Gas Holdings prepaid a portion of the indebtedness, decreasing the balance from $550 million to $225 million, utilizing proceeds received from the Centuri separation transactions. In August 2025, Southwest Gas Holdings paid the remaining balance of $225 million utilizing proceeds received from additional Centuri separation transactions. See Note 6 - Centuri Separation.

The weighted average interest rate of all short-term borrowings is 5.63% at December 31, 2024. There were no short-term borrowings at September 30, 2025.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Section 50
-Paragraph 6
-Subparagraph (b)
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-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
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-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (d)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org/470/tableOfContent

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Long-term debt, less current maturities	$ 3,507,120	$ 3,504,477
Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, less current maturities	3,507,120	3,504,477
Carrying Amount
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	(25,380)	(28,023)
Long-term debt, less current maturities	3,507,120	3,504,477
Carrying Amount \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	3,532,500
Fair Value \| Southwest Gas Corporation
Debt Instrument [Line Items]
Long-term debt, gross	$ 3,236,584	$ 3,121,449

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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+ Details

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References + Details

Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
QRP
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,099	$ 7,063	$ 18,296	$ 21,189
Interest cost	16,397	15,097	49,191	45,291
Expected return on plan assets	(22,582)	(21,953)	(67,745)	(65,859)
Amortization of prior service costs	0	0	0	0
Amortization of net actuarial loss (gain)	751	1,577	2,255	4,731
Net periodic benefit cost	665	1,784	1,997	5,352
SERP
Defined Benefit Plan Disclosure [Line Items]
Service cost	58	61	174	183
Interest cost	596	542	1,788	1,626
Expected return on plan assets	0	0	0	0
Amortization of prior service costs	0	0	0	0
Amortization of net actuarial loss (gain)	270	333	810	999
Net periodic benefit cost	924	936	2,772	2,808
PBOP
Defined Benefit Plan Disclosure [Line Items]
Service cost	292	322	876	966
Interest cost	856	794	2,569	2,383
Expected return on plan assets	(623)	(565)	(1,871)	(1,695)
Amortization of prior service costs	44	44	132	132
Amortization of net actuarial loss (gain)	(78)	0	(235)	0
Net periodic benefit cost	$ 491	$ 595	$ 1,471	$ 1,786

Summary of Significant Accounting Policies - Other Income (Deductions) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Other income (deductions)
Interest income	$ 5,688	$ 8,736	$ 17,315	$ 27,649
Total other income (deductions)	15,367	16,599	42,629	48,918
Corporate and administrative	2,090	(66)	2,244	(58)
Southwest Gas Corporation
Other income (deductions)
Change in COLI policies	2,700	3,200	6,500	7,800
Interest income	5,688	8,736	17,315	27,649
Equity AFUDC	1,501	1,874	4,412	5,548
Other components of net periodic benefit cost	4,369	4,131	13,106	12,392
Miscellaneous income and (expense)	(981)	(1,276)	(948)	(4,413)
Total other income (deductions)	$ 13,277	$ 16,665	$ 40,385	$ 48,976

Segment Information - Narrative (Details) - segment	1 Months Ended		8 Months Ended
Segment Information - Narrative (Details) - segment	Sep. 30, 2025	Aug. 31, 2025	Aug. 31, 2025
Segment Reporting [Abstract]
Number of reportable segments	1	2	2