0001692115-26-000088 | 10-Q | XBRL Viewer | Southwest GAS Holdings INC

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CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share (in USD per share)	$ 0.62	$ 0.62

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, 2024			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	113,870				113,870	(4,696)
Common stock issuances (in shares)			128,000
Common stock issuances	5,543	5,543	$ 128	5,415
Dividends declared	(45,066)	(45,066)				(45,066)
Foreign currency exchange translation adjustment	104	84			84		20
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	268	268			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
Beginning balance (in shares) at Dec. 31, 2025	72,224,593		72,224,000
Beginning balance at Dec. 31, 2025	$ 3,961,119		$ 73,854	2,898,965	(34,546)	1,022,846
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	138,374					138,374
Common stock issuances (in shares)			149,000
Common stock issuances	2,632		$ 149	2,483
Dividends declared	(893)					(893)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	$ 446				446
Ending balance (in shares) at Mar. 31, 2026	72,373,216		72,373,000
Ending balance at Mar. 31, 2026	$ 4,101,678		$ 74,003	$ 2,901,448	$ (34,100)	$ 1,160,327

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

+ References + Details

- Definition

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

+ References

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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - Southwest - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 138,374	$ 109,187
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	99,603	93,690
Deferred income taxes	45,082	35,899
Share-based compensation expense	4,471	4,749
Equity AFUDC	(2,033)	(1,353)
Changes in current assets and liabilities:
Accounts receivable, net of allowance	1,811	(11,122)
Accrued utility revenue	35,700	34,700
Deferred purchased gas costs	(56,759)	59,157
Accounts payable	(73,149)	(44,171)
Accrued taxes	27,817	32,258
Other current assets and liabilities	(16,113)	(17,759)
Changes in deferred charges and other assets	(22,806)	(24,384)
Changes in other liabilities and deferred credits	(19,863)	(20,910)
Net cash provided by operating activities	162,135	291,268
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures and property additions	(208,720)	(163,134)
Changes in customer advances	6,339	(199)
Other	(1,244)	(104)
Net cash provided (used) in investing activities	(203,625)	(186,645)
CASH FLOW FROM FINANCING ACTIVITIES:
Dividends paid	(44,807)	(44,530)
Withholding remittance - share-based compensation	(4,852)	(2,612)
Other, including principal payments on finance leases	(2,892)	(37)
Net cash used in financing activities	(50,403)	(62,128)
Change in cash and cash equivalents, including discontinued operations	(91,893)	42,506
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	41,415	69,975
Income taxes paid, net	(179)	2,418
Decrease of capital expenditures in Accounts payable or Other current liabilities	(29,800)	(19,052)
Equity AFUDC capitalized in regulated operations plant	2,033	1,353
Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	137,771	142,595
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	99,603	93,690
Deferred income taxes	40,247	40,375
Share-based compensation expense	4,126	4,412
Equity AFUDC	(2,033)	(1,353)
Changes in current assets and liabilities:
Accounts receivable, net of allowance		(13,217)
Accrued utility revenue	35,700	34,700
Deferred purchased gas costs	(56,759)	55,862
Accounts payable	(73,296)	(46,688)
Accrued taxes	29,916	33,207
Other current assets and liabilities	(16,151)	(12,181)
Changes in deferred charges and other assets	(23,050)	(24,642)
Changes in other liabilities and deferred credits	(20,386)	(20,928)
Net cash provided by operating activities	213,897	285,832
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures and property additions	(208,720)	(163,134)
Changes in customer advances	6,339	(199)
Other	94	61
Net cash provided (used) in investing activities	(202,287)	(163,272)
CASH FLOW FROM FINANCING ACTIVITIES:
Dividends paid	0	(44,600)
Withholding remittance - share-based compensation	(4,861)	(2,613)
Other, including principal payments on finance leases	(2,892)	(11)
Net cash used in financing activities	(7,753)	(47,224)
Change in cash and cash equivalents, including discontinued operations	3,857	75,336
Cash and cash equivalents, including discontinued operations, at beginning of period	56,408	311,073
Cash and cash equivalents, including discontinued operations, at end of period	60,265	386,409
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	41,415	40,216
Income taxes paid, net	0	0
Decrease of capital expenditures in Accounts payable or Other current liabilities	(29,800)	(10,600)
Equity AFUDC capitalized in regulated operations plant	2,033	1,353
Southwest Gas Corporation \| Nonrelated Party
Changes in current assets and liabilities:
Accounts receivable, net of allowance	1,743	(13,217)
Southwest Gas Corporation \| Related Party
Changes in current assets and liabilities:
Accounts receivable, net of allowance	$ 56,466	$ 0

Revenue (Tables)

3 Months Ended

Mar. 31, 2026

Revenue from Contract with Customer [Abstract]

Schedule of Revenue Disaggregated by Service Type and Contract Type

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 March 31,
(Thousands of dollars)	2026		2025
Residential	$	398,304	$	561,639
Small commercial	88,707		130,365
Large commercial	15,152		21,715
Industrial/other	10,310		13,472
Transportation	30,565		29,566
Revenue from contracts with customers	543,038		756,757
Alternative revenue program revenues	40,145		(12,366)
Other revenues (1)	1,936		2,025
Total Regulated operations revenues(2)	$	585,119	$	746,416

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

(2) The amounts for the three months ended March 31, 2025 differ from Southwest Gas due to the revision discussed in Note 6 - Previously Issued Condensed Consolidated Financial Statement.

Summary of Significant Accounting Policies - Narrative (Details) $ in Millions		1 Months Ended		3 Months Ended
	Aug. 11, 2025 shares	Sep. 30, 2025 segment	Aug. 31, 2025 segment	Mar. 31, 2026 USD ($) segment	Mar. 31, 2025	Dec. 31, 2025 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments \| segment		1	2	1
Gas pipe materials and operating supplies				$ 76.6		$ 78.1
Cloud-based software				37.6		33.9
Accrued property taxes				$ 44.9		27.1
Effective income tax rate				25.00%	20.30%
Decoupling Mechanism
Significant Accounting Policies [Line Items]
Regulatory asset				$ 107.5		91.1
Margin Tracker for Southern Nevada
Significant Accounting Policies [Line Items]
Regulatory asset				35.9		28.5
Accrued Pension And Other Postretirement Benefit Costs
Significant Accounting Policies [Line Items]
Regulatory asset				$ 244.5		246.4
Public Offering And Private Placement
Significant Accounting Policies [Line Items]
Sale of stock, number of shares \| shares	18,823,500
Southwest Gas Corporation
Significant Accounting Policies [Line Items]
Number of reportable segments \| segment				1
Gas pipe materials and operating supplies				$ 76.6		78.1
Cloud-based software				37.6		33.9
Accrued property taxes				$ 44.9		27.1
Effective income tax rate				23.80%	21.50%
Southwest Gas Corporation \| Decoupling Mechanism
Significant Accounting Policies [Line Items]
Regulatory asset				$ 107.5		91.1
Southwest Gas Corporation \| Margin Tracker for Southern Nevada
Significant Accounting Policies [Line Items]
Regulatory asset				35.9		28.5
Southwest Gas Corporation \| Accrued Pension And Other Postretirement Benefit Costs
Significant Accounting Policies [Line Items]
Regulatory asset				$ 244.5		$ 246.4

Previously Issued Condensed Consolidated Financial Statement - Schedule of Effects of the Prior-Period Errors on the Condensed Consolidated Statements of Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 3,961,119	$ 3,681,422
Net income (loss)	138,374	113,870
Ending balance	4,101,678	3,751,445
Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	3,524,966	3,235,486
Net income (loss)	137,771	142,595
Ending balance	3,662,448	3,380,149
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,022,846	758,649
Net income (loss)	138,374	113,870
Ending balance	1,160,327	827,453
Retained Earnings \| Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,314,911	1,059,773
Net income (loss)	137,771	142,595
Ending balance	$ 1,451,880	1,202,052
As Reported \| Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		142,942
Ending balance		3,416,872
As Reported \| Retained Earnings \| Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ending balance		1,238,775
Adjustments \| Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(347)
Ending balance		(36,723)
Adjustments \| Retained Earnings \| Southwest Gas Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ending balance		$ (36,723)

- Definition

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

+ References

+ Details

Revenue - Narrative (Details) $ in Millions	Mar. 31, 2026 USD ($)
Segment Reporting Information [Line Items]
Total operating revenues	$ 53.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01
Segment Reporting Information [Line Items]
Total operating revenues	$ 11.2
Transaction price allocated to unsatisfied performance obligations of contracts, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Segment Reporting Information [Line Items]
Total operating revenues	$ 15.9
Transaction price allocated to unsatisfied performance obligations of contracts, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Segment Reporting Information [Line Items]
Total operating revenues	$ 15.9
Transaction price allocated to unsatisfied performance obligations of contracts, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Segment Reporting Information [Line Items]
Total operating revenues	$ 10.5
Transaction price allocated to unsatisfied performance obligations of contracts, period	1 year

Previously Issued Condensed Consolidated Financial Statement - Schedule of Effects of the Prior-Period Errors on the Condensed Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Regulated operations revenues	$ 585,119	$ 746,416
Operating income	219,346	213,719
Income before income taxes	184,594	168,495
Income tax benefit	46,220	34,207
Net income (loss)	138,374	113,870
Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Regulated operations revenues	585,119	748,516
Operating income	220,844	217,079
Income before income taxes	180,879	181,750
Income tax benefit	43,108	39,155
Net income (loss)	$ 137,771	142,595
As Reported \| Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Regulated operations revenues		746,416
Operating income		214,979
Income before income taxes		179,650
Income tax benefit		36,708
Net income (loss)		142,942
Adjustments \| Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Regulated operations revenues		2,100
Operating income		2,100
Income before income taxes		2,100
Income tax benefit		2,447
Net income (loss)		$ (347)

- 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 + Details

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

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-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-3

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 34: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 35: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 38: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 39: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 40: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 41: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 42: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 43: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-60B

Reference 44: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-7

Reference 45: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 46: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1A

Reference 47: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1B

Reference 48: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (f)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481538/470-20-65-4

Reference 49: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

+ Details

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

+ Details

Debt - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended
Debt - Narrative (Details) - USD ($)	Jun. 30, 2025	Mar. 31, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
Weighted average interest rate		9.23%	9.23%
8% Series, due August 2026 \| Debentures:
Debt Instrument [Line Items]
Debt instrument, stated interest rate		8.00%
Long-term debt, gross		$ 75,000,000.0
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		300,000,000.0
Interest period	7 days
Long-term debt outstanding		0
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Commitment fee, unfunded portion	0.075%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Commitment fee, unfunded portion	0.20%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Line of Credit \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on interest variable rate	0.03839%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		400,000,000.0
Long-term debt outstanding		$ 0
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on variable rate		1.125%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Base Rate
Debt Instrument [Line Items]
Debt, basis spread on variable rate		0.125%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 150,000,000.0
Interest period	7 days
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit \| Minimum
Debt Instrument [Line Items]
Commitment fee, unfunded portion	0.075%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit \| Maximum
Debt Instrument [Line Items]
Commitment fee, unfunded portion	0.20%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt, basis spread on interest variable rate	0.03839%
Revolving Credit Facility \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		250,000,000.0
Bridge Loan \| Revolving Credit Agreement Due August 2029 \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 30,000,000.0
Bridge Loan \| Revolving Credit Agreement Due August 2029 \| Southwest Gas Corporation \| Line of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 30,000,000.0

Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
Less: current maturities	$ 75,000	$ 75,000
Long-term debt, less current maturities	$ 3,433,929	3,433,012
Debentures: \| 8% Series, due August 2026
Debt Instrument [Line Items]
Debt instrument, stated interest rate	8.00%
Long-term debt, gross	$ 75,000
Debentures: \| Medium-term notes, 7.92% series, due June 2027
Debt Instrument [Line Items]
Debt instrument, stated interest rate	7.92%
Debentures: \| Medium-term notes, 6.76% series, due September 2027
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.76%
Debentures: \| Notes, 5.8%, due December 2027
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.80%
Debentures: \| Notes, 3.7%, due April 2028
Debt Instrument [Line Items]
Debt instrument, stated interest rate	3.70%
Debentures: \| Notes, 5.45%, due February 2028
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.45%
Debentures: \| Notes, 2.2%, due June 2030
Debt Instrument [Line Items]
Debt instrument, stated interest rate	2.20%
Debentures: \| Notes, 4.05%, due March 2032
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.05%
Debentures: \| Notes, 6.1%, due February 2041
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.10%
Debentures: \| Notes, 4.875%, due October 2043
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.875%
Debentures: \| Notes, 3.8%, due September 2046
Debt Instrument [Line Items]
Debt instrument, stated interest rate	3.80%
Debentures: \| Notes, 4.15%, due June 2049
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.15%
Debentures: \| Notes, 3.18%, due August 2051
Debt Instrument [Line Items]
Debt instrument, stated interest rate	3.18%
Carrying Amount
Debt Instrument [Line Items]
Less: current maturities	$ 75,000	75,000
Long-term debt, less current maturities	3,433,929	3,433,012
Carrying Amount \| Debentures:
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	(22,367)	(23,207)
Total	3,310,133	3,309,293
Carrying Amount \| Debentures: \| 8% Series, due August 2026
Debt Instrument [Line Items]
Long-term debt, gross	75,000	75,000
Carrying Amount \| Debentures: \| Medium-term notes, 7.92% series, due June 2027
Debt Instrument [Line Items]
Long-term debt, gross	25,000	25,000
Carrying Amount \| Debentures: \| Medium-term notes, 6.76% series, due September 2027
Debt Instrument [Line Items]
Long-term debt, gross	7,500	7,500
Carrying Amount \| Debentures: \| Notes, 5.8%, due December 2027
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures: \| Notes, 3.7%, due April 2028
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures: \| Notes, 5.45%, due February 2028
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures: \| Notes, 2.2%, due June 2030
Debt Instrument [Line Items]
Long-term debt, gross	450,000	450,000
Carrying Amount \| Debentures: \| Notes, 4.05%, due March 2032
Debt Instrument [Line Items]
Long-term debt, gross	600,000	600,000
Carrying Amount \| Debentures: \| Notes, 6.1%, due February 2041
Debt Instrument [Line Items]
Long-term debt, gross	125,000	125,000
Carrying Amount \| Debentures: \| Notes, 4.875%, due October 2043
Debt Instrument [Line Items]
Long-term debt, gross	250,000	250,000
Carrying Amount \| Debentures: \| Notes, 3.8%, due September 2046
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures: \| Notes, 4.15%, due June 2049
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Debentures: \| Notes, 3.18%, due August 2051
Debt Instrument [Line Items]
Long-term debt, gross	300,000	300,000
Carrying Amount \| Industrial development revenue bonds:
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	(1,204)	(1,281)
Total	198,796	198,719
Carrying Amount \| Industrial development revenue bonds: \| Tax-exempt Series A, due December 2028
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds: \| 2003 Series A, due March 2038
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds: \| 2008 Series A, due March 2038
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Carrying Amount \| Industrial development revenue bonds: \| 2009 Series A, due December 2039
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Debentures: \| 8% Series, due August 2026
Debt Instrument [Line Items]
Long-term debt, gross	75,813	76,388
Fair Value \| Debentures: \| Medium-term notes, 7.92% series, due June 2027
Debt Instrument [Line Items]
Long-term debt, gross	25,850	26,058
Fair Value \| Debentures: \| Medium-term notes, 6.76% series, due September 2027
Debt Instrument [Line Items]
Long-term debt, gross	7,679	7,726
Fair Value \| Debentures: \| Notes, 5.8%, due December 2027
Debt Instrument [Line Items]
Long-term debt, gross	306,480	309,090
Fair Value \| Debentures: \| Notes, 3.7%, due April 2028
Debt Instrument [Line Items]
Long-term debt, gross	296,370	297,450
Fair Value \| Debentures: \| Notes, 5.45%, due February 2028
Debt Instrument [Line Items]
Long-term debt, gross	305,730	307,620
Fair Value \| Debentures: \| Notes, 2.2%, due June 2030
Debt Instrument [Line Items]
Long-term debt, gross	409,455	409,365
Fair Value \| Debentures: \| Notes, 4.05%, due March 2032
Debt Instrument [Line Items]
Long-term debt, gross	573,000	579,540
Fair Value \| Debentures: \| Notes, 6.1%, due February 2041
Debt Instrument [Line Items]
Long-term debt, gross	128,913	130,762
Fair Value \| Debentures: \| Notes, 4.875%, due October 2043
Debt Instrument [Line Items]
Long-term debt, gross	215,525	219,350
Fair Value \| Debentures: \| Notes, 3.8%, due September 2046
Debt Instrument [Line Items]
Long-term debt, gross	225,000	228,180
Fair Value \| Debentures: \| Notes, 4.15%, due June 2049
Debt Instrument [Line Items]
Long-term debt, gross	230,160	237,120
Fair Value \| Debentures: \| Notes, 3.18%, due August 2051
Debt Instrument [Line Items]
Long-term debt, gross	194,100	205,710
Fair Value \| Industrial development revenue bonds: \| Tax-exempt Series A, due December 2028
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds: \| 2003 Series A, due March 2038
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds: \| 2008 Series A, due March 2038
Debt Instrument [Line Items]
Long-term debt, gross	50,000	50,000
Fair Value \| Industrial development revenue bonds: \| 2009 Series A, due December 2039
Debt Instrument [Line Items]
Long-term debt, gross	$ 50,000	$ 50,000

CONDENSED CONSOLIDATED BALANCE SHEETS - Southwest - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Regulated operations plant:
Gas plant	$ 11,659,807	$ 11,517,031
Less: accumulated depreciation	(3,113,118)	(3,063,363)
Construction work in progress	259,867	236,871
Net regulated operations plant	8,806,556	8,690,539
Other property and investments, net	177,632	178,826
Current assets:
Cash and cash equivalents	484,752	576,645
Accounts receivable, net of allowances	168,790	170,601
Accrued utility revenue	65,900	101,600
Income taxes receivable, net	6,317	9,611
Deferred purchased gas costs	0	5,214
Materials, supplies, and gas inventories	93,656	93,823
Prepaid and other current assets	238,259	234,598
Total current assets	1,057,674	1,192,092
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	353,629	356,865
Total noncurrent assets	364,784	368,020
Total assets	10,406,646	10,429,477
Capitalization:
Common stock	74,003	73,854
Additional paid-in capital	2,901,448	2,898,965
Accumulated other comprehensive loss, net	(34,100)	(34,546)
Retained earnings	1,160,327	1,022,846
Total equity	4,101,678	3,961,119
Long-term debt, less current maturities	3,433,929	3,433,012
Total capitalization	7,535,607	7,394,131
Current liabilities:
Current maturities of long-term debt	75,000	75,000
Accounts payable	122,008	225,732
Customer deposits	67,607	67,249
Accrued general taxes	78,907	54,384
Accrued interest	38,329	35,319
Deferred purchased gas costs	248,112	310,085
Other current liabilities	99,995	117,350
Total current liabilities	729,958	929,898
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	1,022,534	977,312
Accumulated removal costs	504,000	496,000
Other deferred credits and other long-term liabilities	614,547	632,136
Total deferred income taxes and other credits	2,141,081	2,105,448
Total capitalization and liabilities	10,406,646	10,429,477
Southwest Gas Corporation
Regulated operations plant:
Gas plant	11,659,807	11,517,031
Less: accumulated depreciation	(3,113,118)	(3,063,363)
Construction work in progress	259,867	236,871
Net regulated operations plant	8,806,556	8,690,539
Other property and investments, net	167,558	169,947
Current assets:
Cash and cash equivalents	60,265	56,408
Accrued utility revenue	65,900	101,600
Income taxes receivable, net	0	1,007
Deferred purchased gas costs	0	5,214
Materials, supplies, and gas inventories	93,656	93,823
Prepaid and other current assets	237,638	234,003
Total current assets	675,324	768,129
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	351,149	354,221
Total noncurrent assets	362,304	365,376
Total assets	10,011,742	9,993,991
Capitalization:
Common stock	49,112	49,112
Additional paid-in capital	2,195,556	2,195,489
Accumulated other comprehensive loss, net	(34,100)	(34,546)
Retained earnings	1,451,880	1,314,911
Total equity	3,662,448	3,524,966
Long-term debt, less current maturities	3,433,929	3,433,012
Total capitalization	7,096,377	6,957,978
Current liabilities:
Current maturities of long-term debt	75,000	75,000
Customer deposits	67,607	67,249
Income taxes payable	4,386	0
Accrued general taxes	78,907	54,384
Accrued interest	38,329	35,319
Deferred purchased gas costs	248,112	310,085
Other current liabilities	99,995	117,350
Total current liabilities	733,802	884,724
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	1,068,309	1,027,921
Accumulated removal costs	504,000	496,000
Other deferred credits and other long-term liabilities	609,254	627,368
Total deferred income taxes and other credits	2,181,563	2,151,289
Total capitalization and liabilities	10,011,742	9,993,991
Southwest Gas Corporation \| Related Party
Current assets:
Accounts receivable, net of allowances	49,084	105,550
Southwest Gas Corporation \| Nonrelated Party
Current assets:
Accounts receivable, net of allowances	168,781	170,524
Current liabilities:
Accounts payable	$ 121,466	$ 225,337

Summary of Significant Accounting Policies - Schedule of Significant Items Included in Other Income (Deductions) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Other income (deductions)
Interest income	$ 4,130	$ 35
Equity in earnings of unconsolidated investments	1,194	0
Equity AFUDC	2,033	1,353
Miscellaneous income and (expense)	(48)	(142)
Total other income (deductions)	10,991	9,195
Southwest Gas Corporation
Other income (deductions)
Change in COLI policies	(300)	(1,700)
Interest income	2,654	5,810
Equity AFUDC	2,033	1,353
Other components of net periodic benefit cost	2,195	4,369
Miscellaneous income and (expense)	(867)	(530)
Total other income (deductions)	$ 5,715	$ 9,302

- Definition

Amount of income (loss) for proportionate share of equity method investee's income (loss).

+ References + Details

Previously Issued Condensed Consolidated Financial Statement - Schedule of Effects of the Prior-Period Errors on the Condensed Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ 138,374	$ 109,187
Comprehensive income (loss)	138,820	109,559
Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)	137,771	142,595
Comprehensive income (loss)	$ 138,217	142,863
As Reported \| Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)		142,942
Comprehensive income (loss)		143,210
Adjustments \| Southwest Gas Corporation
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(347)
Comprehensive income (loss)		$ (347)

- 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

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 + Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478671/942-235-S50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-1

Reference 3: 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 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
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+ Details

Background and Organization (Details) - segment	1 Months Ended		3 Months Ended
Background and Organization (Details) - segment	Sep. 30, 2025	Aug. 31, 2025	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	1	2	1

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2026

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)	March 31, 2026		December 31, 2025
Net cash surrender value of COLI policies	$	165,284	$	165,551
Other property	2,274		4,396
Total Southwest Gas Corporation	167,558		169,947


Other property and investments	10,074		8,879
Total Southwest Gas Holdings, Inc.	$	177,632	$	178,826

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 March 31,
(Thousands of dollars)	2026		2025
Southwest Gas Corporation:
Change in COLI policies	$	(300)	$	(1,700)
Interest income	2,654		5,810
Equity AFUDC	2,033		1,353
Other components of net periodic benefit cost	2,195		4,369
Miscellaneous income and (expense)	(867)		(530)
Southwest Gas Corporation - total other income (deductions)	5,715		9,302
Southwest Gas Holdings, Inc.:

Interest income	4,130		35
Equity in earnings of unconsolidated investments	1,194		—
Miscellaneous income and (expense)	(48)		(142)
Southwest Gas Holdings, Inc. – total other income (deductions)	$	10,991	$	9,195

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 March 31,
(In thousands)	2026	2025
Weighted average basic shares	72,441	72,012
Effect of dilutive securities:
Restricted stock units (1)(2)	125	126
Weighted average diluted shares	72,566	72,138

(1) The number of securities included 105,000 and 110,000 performance stock units during the three months ended March 31, 2026 and March 31, 2025, respectively, 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 discontinued operations during the three months ended March 31, 2025 is 126,000.

Previously Issued Condensed Consolidated Financial Statement - Schedule of Effects of the Prior-Period Errors on the Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025
CAPITALIZATION AND LIABILITIES
Retained earnings	$ 1,160,327	$ 1,022,846
Total equity	4,101,678	3,961,119
Total capitalization	7,535,607	7,394,131
Deferred income taxes and investment tax credits, net	1,022,534	977,312
Total deferred income taxes and other credits	2,141,081	2,105,448
Total capitalization and liabilities	10,406,646	10,429,477
Southwest Gas Corporation
CAPITALIZATION AND LIABILITIES
Retained earnings	1,451,880	1,314,911	$ 1,202,052
Total equity	3,662,448	3,524,966	3,380,149
Total capitalization	7,096,377	6,957,978	6,885,501
Deferred income taxes and investment tax credits, net	1,068,309	1,027,921	894,709
Total deferred income taxes and other credits	2,181,563	2,151,289	2,061,958
Total capitalization and liabilities	$ 10,011,742	$ 9,993,991	9,679,467
As Reported \| Southwest Gas Corporation
CAPITALIZATION AND LIABILITIES
Retained earnings			1,238,775
Total equity			3,416,872
Total capitalization			6,922,224
Deferred income taxes and investment tax credits, net			857,986
Total deferred income taxes and other credits			2,025,235
Total capitalization and liabilities			9,679,467
Adjustments \| Southwest Gas Corporation
CAPITALIZATION AND LIABILITIES
Retained earnings			(36,723)
Total equity			(36,723)
Total capitalization			(36,723)
Deferred income taxes and investment tax credits, net			36,723
Total deferred income taxes and other credits			36,723
Total capitalization and liabilities			$ 0

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2026

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 2025 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. 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 condensed consolidated financial statements.

In addition, the sale of Centuri, which comprised the Company’s Utility Infrastructure Services segment, represented a strategic shift that had a significant impact on the Company’s operations and financial results. Therefore, Centuri met 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. 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 prior period amounts have been recast to reflect discontinued operations.

Segment Information. The Company’s CEO and Southwest Gas’ CEO and Southwest Gas’ President have been identified as the CODM for each Company respectively. The CODM reviews the Company’s income (loss) from continuing operations and Southwest Gas’ net income as reported on their respective condensed consolidated statements of income in assessing performance and allocating resources. The CODM considers budget-to-actual variances against these metrics when making decisions about allocating capital and personnel. The CODM also uses income (loss) from continuing operations and net income to assess the return on assets, margin earned, and in assessing the compensation of certain employees.

Because both the Company and Southwest Gas operate as a single reportable segment, the related disclosure information is presented in the applicable sections. The other significant amounts required for disclosure are included within income (loss) from continuing operations and net income. Revenues from external customers are reported as “Revenues from contracts with customers” in Note 3 – Revenue for the quarters ended March 31, 2026, and March 31, 2025, and capital expenditures are reported as “Capital expenditures and property additions” in the condensed consolidated statements of cash flows for the quarters ended March 31, 2026 and March 31, 2025. The measures of assets for the Company and Southwest Gas are reported as “Total assets” on their respective condensed consolidated balance sheets.

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 2025 Annual Report on Form 10-K for the fiscal year ended December 31, 2025.

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


(Thousands of dollars)	March 31, 2026		December 31, 2025
Net cash surrender value of COLI policies	$	165,284	$	165,551
Other property	2,274		4,396
Total Southwest Gas Corporation	167,558		169,947


Other property and investments	10,074		8,879
Total Southwest Gas Holdings, Inc.	$	177,632	$	178,826

Materials, supplies, and gas inventories. Materials, supplies, and gas inventories for Southwest Gas and the Company includes gas pipe materials and operating supplies of $76.6 million and $78.1 million as of March 31, 2026 and December 31, 2025, respectively (carried at weighted average cost).

Prepaid and other current assets. Prepaid and other current assets for the Company and Southwest Gas include, among other things, $107.5 million and $91.1 million related to a regulatory asset associated with the Arizona decoupling mechanism as of March 31, 2026 and December 31, 2025, respectively, and regulatory asset associated with margin tracker for Southern Nevada of $35.9 million and $28.5 million as of March 31, 2026 and December 31, 2025, respectively.

Deferred charges and other assets. Deferred charges and other assets for Southwest Gas and the Company include, among other things, cloud-based software of $37.6 million and $33.9 million as of March 31, 2026 and December 31, 2025, respectively, regulatory asset associated with pension for Arizona and Nevada of $244.5 million and $246.4 million as of March 31, 2026 and December 31, 2025, respectively.

Accrued general taxes. Accrued general taxes for the Company and Southwest Gas include, among other things, $44.9 million and $27.1 million related to property taxes accrued as of March 31, 2026 and December 31, 2025.

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 March 31,
(Thousands of dollars)	2026		2025
Southwest Gas Corporation:
Change in COLI policies	$	(300)	$	(1,700)
Interest income	2,654		5,810
Equity AFUDC	2,033		1,353
Other components of net periodic benefit cost	2,195		4,369
Miscellaneous income and (expense)	(867)		(530)
Southwest Gas Corporation - total other income (deductions)	5,715		9,302
Southwest Gas Holdings, Inc.:

Interest income	4,130		35
Equity in earnings of unconsolidated investments	1,194		—
Miscellaneous income and (expense)	(48)		(142)
Southwest Gas Holdings, Inc. – total other income (deductions)	$	10,991	$	9,195

Interest income for Southwest Gas relates to interest income earned on money market investments and interest income earned on Southwest Gas’ regulatory asset balances, including the Arizona decoupling mechanism. Interest income is earned on regulatory asset balances and interest expense is incurred on regulatory liability balances. Interest income for Southwest Gas Holdings, Inc. relates to interest income earned on money market investments. 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 March 31,
(In thousands)	2026	2025
Weighted average basic shares	72,441	72,012
Effect of dilutive securities:
Restricted stock units (1)(2)	125	126
Weighted average diluted shares	72,566	72,138

(2) The number of anti-dilutive restricted stock units excluded from the calculation of diluted shares from discontinued operations during the three months ended March 31, 2025 is 126,000.

Income Taxes. The Company’s effective tax rate was 25.0% for the three months ended March 31, 2026, compared to 20.3% for the corresponding period in 2025. The higher effective tax rate was primarily due to pre-tax income differences, the amortization of excess deferred income taxes, nondeductible executive compensation, and state income taxes.

Southwest Gas’ effective tax rate was 23.8% for the three months ended March 31, 2026, compared to 21.5% for the corresponding period in 2025. The higher effective tax rate was primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and nondeductible executive compensation.

Recent Accounting Standards Updates.

Recently issued accounting pronouncements that will be effective in 2026 and thereafter:

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 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’ condensed consolidated financial statements.

Background and Organization	3 Months Ended
Background and Organization	Mar. 31, 2026
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, a California corporation. The Company’s common stock trades under the ticker symbol “SWX.” Until the deconsolidation of Centuri in August 2025, the Company’s businesses were managed within two separate reportable segments, 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. 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.

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2026	May 01, 2026
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2026
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		72,374,873
Entity Central Index Key	0001692115
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
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	Mar. 31, 2026
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	2026
Document Fiscal Period Focus	Q1
Amendment Flag	false
Current Fiscal Year End Date	--12-31

Debt

3 Months Ended

Mar. 31, 2026

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.


	March 31,				December 31,
	2026				2025
(Thousands of dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Southwest Gas Holdings, Inc. and Southwest Gas Corporation:
Debentures:
8% Series, due August 2026	$	75,000	$	75,813	$	75,000	$	76,388
Medium-term notes, 7.92% series, due June 2027	25,000		25,850		25,000		26,058
Medium-term notes, 6.76% series, due September 2027	7,500		7,679		7,500		7,726
Notes, 5.8%, due December 2027	300,000		306,480		300,000		309,090
Notes, 3.7%, due April 2028	300,000		296,370		300,000		297,450
Notes, 5.45%, due February 2028	300,000		305,730		300,000		307,620
Notes, 2.2%, due June 2030	450,000		409,455		450,000		409,365
Notes, 4.05%, due March 2032	600,000		573,000		600,000		579,540
Notes, 6.1%, due February 2041	125,000		128,913		125,000		130,762
Notes, 4.875%, due October 2043	250,000		215,525		250,000		219,350
Notes, 3.8%, due September 2046	300,000		225,000		300,000		228,180
Notes, 4.15%, due June 2049	300,000		230,160		300,000		237,120
Notes, 3.18%, due August 2051	300,000		194,100		300,000		205,710
Unamortized discount and debt issuance costs	(22,367)				(23,207)
	3,310,133				3,309,293

Industrial development revenue bonds:
Tax-exempt Series A, due December 2028	50,000		50,000		50,000		50,000
2003 Series A, due March 2038	50,000		50,000		50,000		50,000
2008 Series A, due March 2038	50,000		50,000		50,000		50,000
2009 Series A, due December 2039	50,000		50,000		50,000		50,000
Unamortized discount and debt issuance costs	(1,204)				(1,281)
	198,796				198,719
Less: current maturities	75,000				75,000
Southwest Gas Holdings, Inc. and Southwest Gas Corporation total long-term debt, less current maturities	$	3,433,929			$	3,433,012

Southwest Gas has a $400.0 million revolving credit facility that is scheduled to expire in August 2029. Southwest Gas designates $150.0 million of associated capacity as long-term debt and the remaining $250.0 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 $30.0 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. Southwest Gas is also required to pay a commitment fee on the unfunded portion of the commitments which ranges from 0.075% to 0.200%. At March 31, 2026, the applicable margin was 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 March 31, 2026, 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

Southwest Gas Holdings has a $300.0 million revolving credit agreement that is scheduled to expire in August 2029. At March 31, 2026, the applicable margin is 1.125% for loans bearing interest to SOFR and 0.125% 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 $30.0 million. At March 31, 2026, there were no borrowings outstanding under this credit facility.

As indicated above in the Long-Term debt table, the 8% Series debenture for $75.0 million matures in August 2026.

The weighted average interest rate of all short-term borrowings was 9.23% at March 31, 2026 and December 31, 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
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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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
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-Publisher FASB
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2026
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, a California corporation. The Company’s common stock trades under the ticker symbol “SWX.” Until the deconsolidation of Centuri in August 2025, the Company’s businesses were managed within two separate reportable segments, 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. 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 2025 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. 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 condensed consolidated financial statements. In addition, the sale of Centuri, which comprised the Company’s Utility Infrastructure Services segment, represented a strategic shift that had a significant impact on the Company’s operations and financial results. Therefore, Centuri met 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. 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 prior period amounts have been recast to reflect discontinued operations.
Segment Information	Segment Information. The Company’s CEO and Southwest Gas’ CEO and Southwest Gas’ President have been identified as the CODM for each Company respectively. The CODM reviews the Company’s income (loss) from continuing operations and Southwest Gas’ net income as reported on their respective condensed consolidated statements of income in assessing performance and allocating resources. The CODM considers budget-to-actual variances against these metrics when making decisions about allocating capital and personnel. The CODM also uses income (loss) from continuing operations and net income to assess the return on assets, margin earned, and in assessing the compensation of certain employees. Because both the Company and Southwest Gas operate as a single reportable segment, the related disclosure information is presented in the applicable sections. The other significant amounts required for disclosure are included within income (loss) from continuing operations and net income. Revenues from external customers are reported as “Revenues from contracts with customers” in Note 3 – Revenue for the quarters ended March 31, 2026, and March 31, 2025, and capital expenditures are reported as “Capital expenditures and property additions” in the condensed consolidated statements of cash flows for the quarters ended March 31, 2026 and March 31, 2025. The measures of assets for the Company and Southwest Gas are reported as “Total assets” on their respective condensed consolidated balance sheets.
Materials, supplies, and gas inventories	Materials, supplies, and gas inventories. Materials, supplies, and gas inventories for Southwest Gas and the Company includes gas pipe materials and operating supplies of $76.6 million and $78.1 million as of March 31, 2026 and December 31, 2025, respectively (carried at weighted average cost).
Prepaid and other current assets	Prepaid and other current assets. Prepaid and other current assets for the Company and Southwest Gas include, among other things, $107.5 million and $91.1 million related to a regulatory asset associated with the Arizona decoupling mechanism as of March 31, 2026 and December 31, 2025, respectively, and regulatory asset associated with margin tracker for Southern Nevada of $35.9 million and $28.5 million as of March 31, 2026 and December 31, 2025, respectively.
Deferred charges and other assets	Deferred charges and other assets. Deferred charges and other assets for Southwest Gas and the Company include, among other things, cloud-based software of $37.6 million and $33.9 million as of March 31, 2026 and December 31, 2025, respectively, regulatory asset associated with pension for Arizona and Nevada of $244.5 million and $246.4 million as of March 31, 2026 and December 31, 2025, respectively
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 25.0% for the three months ended March 31, 2026, compared to 20.3% for the corresponding period in 2025. The higher effective tax rate was primarily due to pre-tax income differences, the amortization of excess deferred income taxes, nondeductible executive compensation, and state income taxes. Southwest Gas’ effective tax rate was 23.8% for the three months ended March 31, 2026, compared to 21.5% for the corresponding period in 2025. The higher effective tax rate was primarily due to pre-tax income differences, the amortization of excess deferred income taxes, and nondeductible executive compensation.
Recent Accounting Standards Updates	Recent Accounting Standards Updates. Recently issued accounting pronouncements that will be effective in 2026 and thereafter: 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 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’ condensed consolidated financial statements.

Previously Issued Condensed Consolidated Financial Statement - Schedule of Effects of the Prior-Period Errors on the Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	$ 138,374	$ 109,187
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	45,082	35,899
Changes in current assets and liabilities:
Accounts receivable, net of allowances	1,811	(11,122)
Deferred purchased gas costs	(56,759)	59,157
Accounts payable	(73,149)	(44,171)
Net cash provided by operating activities	162,135	291,268
Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	137,771	142,595
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	40,247	40,375
Changes in current assets and liabilities:
Accounts receivable, net of allowances		(13,217)
Deferred purchased gas costs	(56,759)	55,862
Accounts payable	(73,296)	(46,688)
Net cash provided by operating activities	$ 213,897	285,832
As Reported \| Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)		142,942
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes		37,928
Changes in current assets and liabilities:
Accounts receivable, net of allowances		(11,117)
Deferred purchased gas costs		53,865
Accounts payable		(44,691)
Net cash provided by operating activities		285,832
Adjustments \| Southwest Gas Corporation
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)		(347)
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes		2,447
Changes in current assets and liabilities:
Accounts receivable, net of allowances		(2,100)
Deferred purchased gas costs		1,997
Accounts payable		(1,997)
Net cash provided by operating activities		$ 0

Components of Net Periodic Benefit Cost

3 Months Ended

Mar. 31, 2026

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 months ended March 31, 2026 and 2025 are presented in the following tables.


	Three Months Ended March 31,
	2026						2025
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	6,467	$	52	$	299	$	6,098	$	58	$	292
Interest cost	16,726		589		835		16,397		596		856
Expected return on plan assets	(22,221)		—		(694)		(22,582)		—		(624)
Amortization of prior service costs	—		—		44		—		—		44
Amortization of net actuarial loss (gain)	2,295		334		(103)		752		270		(78)
Net periodic benefit cost	$	3,267	$	975	$	381	$	665	$	924	$	490

Summary of Significant Accounting Policies - Schedule of Other Property and Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Property, Plant and Equipment [Line Items]
Other property and investments	$ 10,074	$ 8,879
Total	177,632	178,826
Southwest Gas Corporation
Property, Plant and Equipment [Line Items]
Net cash surrender value of COLI policies	165,284	165,551
Other property and investments	2,274	4,396
Total	$ 167,558	$ 169,947

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Net income	$ 138,374	$ 109,187
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11 and $11, respectively	33	33
Amortization of net actuarial loss, net of tax of $606 and $226, respectively	1,920	718
Regulatory adjustment, net of tax of ($477) and ($152), respectively	(1,507)	(483)
Net defined benefit pension plans, net of tax	446	268
Total other comprehensive income, net of tax	446	372
Comprehensive income	138,820	109,559
Southwest Gas Corporation
Net income	137,771	142,595
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11 and $11, respectively	33	33
Amortization of net actuarial loss, net of tax of $606 and $226, respectively	1,920	718
Regulatory adjustment, net of tax of ($477) and ($152), respectively	(1,507)	(483)
Net defined benefit pension plans, net of tax	446	268
Total other comprehensive income, net of tax	446	268
Comprehensive income	$ 138,217	$ 142,863

- Definition

+ References + Details

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 10
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-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(21))
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1B

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1A

+ Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

+ Details

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Regulated operations plant:
Gas plant	$ 11,659,807	$ 11,517,031
Less: accumulated depreciation	(3,113,118)	(3,063,363)
Construction work in progress	259,867	236,871
Net regulated operations plant	8,806,556	8,690,539
Other property and investments, net	177,632	178,826
Current assets:
Cash and cash equivalents	484,752	576,645
Accounts receivable, net of allowances	168,790	170,601
Accrued utility revenue	65,900	101,600
Income taxes receivable, net	6,317	9,611
Deferred purchased gas costs	0	5,214
Materials, supplies, and gas inventories	93,656	93,823
Prepaid and other current assets	238,259	234,598
Total current assets	1,057,674	1,192,092
Noncurrent assets:
Goodwill	11,155	11,155
Deferred charges and other assets	353,629	356,865
Total noncurrent assets	364,784	368,020
Total assets	10,406,646	10,429,477
Capitalization:
Common stock, $1 par (authorized - 120,000,000 shares; issued and outstanding - 72,373,216 and 72,224,593 shares)	74,003	73,854
Additional paid-in capital	2,901,448	2,898,965
Accumulated other comprehensive loss, net	(34,100)	(34,546)
Retained earnings	1,160,327	1,022,846
Total equity	4,101,678	3,961,119
Long-term debt, less current maturities	3,433,929	3,433,012
Total capitalization	7,535,607	7,394,131
Current liabilities:
Current maturities of long-term debt	75,000	75,000
Accounts payable	122,008	225,732
Customer deposits	67,607	67,249
Accrued general taxes	78,907	54,384
Accrued interest	38,329	35,319
Deferred purchased gas costs	248,112	310,085
Dividends declared	0	44,779
Other current liabilities	99,995	117,350
Total current liabilities	729,958	929,898
Deferred income taxes and other credits:
Deferred income taxes and investment tax credits, net	1,022,534	977,312
Accumulated removal costs	504,000	496,000
Other deferred credits and other long-term liabilities	614,547	632,136
Total deferred income taxes and other credits	2,141,081	2,105,448
Total capitalization and liabilities	$ 10,406,646	$ 10,429,477

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating revenues:
Regulated operations revenues	$ 585,119	$ 746,416
Total operating revenues	585,119	746,416
Operating expenses:
Net cost of gas sold	108,154	284,579
Operations and maintenance	133,001	130,667
Depreciation and amortization	99,603	93,690
Taxes other than income taxes	25,015	23,761
Total operating expenses	365,773	532,697
Operating income	219,346	213,719
Other income and (expenses):
Net interest deductions	(45,743)	(54,419)
Other income	10,991	9,195
Total other (expenses)	(34,752)	(45,224)
Income from continuing operations before income taxes	184,594	168,495
Income tax expense	46,220	34,207
Income from continuing operations	138,374	134,288
Loss from discontinued operations, net of income tax	0	(25,101)
Net income	138,374	109,187
Net loss attributable to noncontrolling interests	0	(4,683)
Net income	$ 138,374	$ 113,870
Basic earnings (loss) per share:
Continuing operations (in USD per share)	$ 1.91	$ 1.86
Discontinued operations (in USD per share)	0	(0.28)
Net earnings per share - basic (in USD per share)	1.91	1.58
Diluted earnings (loss) per share:
Continuing operations (in USD per share)	1.91	1.86
Discontinued operations (in USD per share)	0	(0.28)
Net earnings per share - diluted (in USD per share)	$ 1.91	$ 1.58
Weighted average shares:
Basic (in shares)	72,441	72,012
Diluted (in shares)	72,566	72,138

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - Southwest - USD ($) $ in Thousands	Total	Southwest Gas Corporation	Common stock shares	Common stock shares 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, 2024			71,783,000	47,482,000
Beginning balance at Dec. 31, 2024	$ 3,681,422	$ 3,235,486	$ 73,413	$ 49,112	$ 2,721,343	$ 2,165,002	$ (49,218)	$ (38,401)	$ 758,649	$ 1,059,773
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	113,870	142,595							113,870	142,595
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	3,380,149	$ 73,541	$ 49,112	2,726,758	2,167,118	(48,866)	(38,133)	827,453	1,202,052
Beginning balance (in shares) at Dec. 31, 2025	72,224,593		72,224,000	47,482,000
Beginning balance at Dec. 31, 2025	$ 3,961,119	3,524,966	$ 73,854	$ 49,112	2,898,965	2,195,489	(34,546)	(34,546)	1,022,846	1,314,911
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	138,374	137,771							138,374	137,771
Share-based compensation		(735)				67				(802)
Net actuarial gain arising during period, less amortization of unamortized benefit plan cost, net of tax	$ 446	446					446	446
Ending balance (in shares) at Mar. 31, 2026	72,373,216		72,373,000	47,482,000
Ending balance at Mar. 31, 2026	$ 4,101,678	$ 3,662,448	$ 74,003	$ 49,112	$ 2,901,448	$ 2,195,556	$ (34,100)	$ (34,100)	$ 1,160,327	$ 1,451,880

- Definition

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

+ References

+ Details

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - Southwest - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Amortization of prior service cost, tax	$ 11	$ 11
Amortization of net actuarial loss, tax	606	226
Regulatory adjustment, tax	(477)	(152)
Southwest Gas Corporation
Amortization of prior service cost, tax	11	11
Amortization of net actuarial loss, tax	606	226
Regulatory adjustment, tax	$ (477)	$ (152)

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2026
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
QRP
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,467	$ 6,098
Interest cost	16,726	16,397
Expected return on plan assets	(22,221)	(22,582)
Amortization of prior service costs	0	0
Amortization of net actuarial loss (gain)	2,295	752
Net periodic benefit cost	3,267	665
SERP
Defined Benefit Plan Disclosure [Line Items]
Service cost	52	58
Interest cost	589	596
Expected return on plan assets	0	0
Amortization of prior service costs	0	0
Amortization of net actuarial loss (gain)	334	270
Net periodic benefit cost	975	924
PBOP
Defined Benefit Plan Disclosure [Line Items]
Service cost	299	292
Interest cost	835	856
Expected return on plan assets	(694)	(624)
Amortization of prior service costs	44	44
Amortization of net actuarial loss (gain)	(103)	(78)
Net periodic benefit cost	$ 381	$ 490

Revenue - Schedule of Revenue Disaggregated by Service Type and Contract Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Total Regulated operations revenues	$ 585,119	$ 746,416
Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	543,038	756,757
Alternative revenue program revenues	40,145	(12,366)
Other revenues	1,936	2,025
Total Regulated operations revenues	585,119	746,416
Residential \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	398,304	561,639
Small commercial \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	88,707	130,365
Large commercial \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,152	21,715
Industrial/other \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,310	13,472
Transportation \| Southwest Gas Corporation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 30,565	$ 29,566

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - Southwest - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Regulated operations revenues	$ 585,119	$ 746,416
Operating expenses:
Net cost of gas sold	108,154	284,579
Operations and maintenance	133,001	130,667
Depreciation and amortization	99,603	93,690
Taxes other than income taxes	25,015	23,761
Total operating expenses	365,773	532,697
Operating income	219,346	213,719
Other income and (expenses):
Net interest deductions	(45,743)	(54,419)
Other income	10,991	9,195
Total other (expenses)	(34,752)	(45,224)
Income from continuing operations before income taxes	184,594	168,495
Income tax expense	46,220	34,207
Net income	138,374	113,870
Southwest Gas Corporation
Regulated operations revenues	585,119	748,516
Operating expenses:
Net cost of gas sold	108,154	284,579
Operations and maintenance	131,503	129,407
Depreciation and amortization	99,603	93,690
Taxes other than income taxes	25,015	23,761
Total operating expenses	364,275	531,437
Operating income	220,844	217,079
Other income and (expenses):
Net interest deductions	(45,680)	(44,631)
Other income	5,715	9,302
Total other (expenses)	(39,965)	(35,329)
Income from continuing operations before income taxes	180,879	181,750
Income tax expense	43,108	39,155
Net income	$ 137,771	$ 142,595

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 138,374	$ 109,187
Less: Income (loss) from discontinued operations, net of income tax	0	(25,101)
Income from continuing operations, net of income tax	138,374	134,288
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	99,603	93,690
Deferred income taxes	45,082	35,899
Share-based compensation expense	4,471	4,749
Equity AFUDC	(2,033)	(1,353)
Changes in current assets and liabilities:
Accounts receivable, net of allowances	1,811	(11,122)
Accrued utility revenue	35,700	34,700
Deferred purchased gas costs	(56,759)	59,157
Accounts payable	(73,149)	(44,171)
Accrued taxes	27,817	32,258
Other current assets and liabilities	(16,113)	(17,759)
Changes in deferred charges and other assets	(22,806)	(24,384)
Changes in other liabilities and deferred credits	(19,863)	(20,910)
Net cash provided by operating activities of continuing operations	162,135	275,042
Net cash provided (used) by operating activities of discontinued operations	0	16,226
Net cash provided by operating activities	162,135	291,268
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures and property additions	(208,720)	(163,134)
Changes in customer advances	6,339	(199)
Other	(1,244)	(104)
Net cash used in investing activities of continuing operations	(203,625)	(163,437)
Net cash provided (used) in investing activities of discontinued operations	0	(23,208)
Net cash provided (used) in investing activities	(203,625)	(186,645)
CASH FLOW FROM FINANCING ACTIVITIES:
Issuance of common stock, net	2,148	2,295
Dividends paid	(44,807)	(44,530)
Change in short-term portion of credit facility	0	10,000
Withholding remittance - share-based compensation	(4,852)	(2,612)
Other, including principal payments on finance leases	(2,892)	(37)
Net cash used in financing activities of continuing operations	(50,403)	(34,884)
Net cash provided (used) in financing activities of discontinued operations	0	(27,244)
Net cash used in financing activities	(50,403)	(62,128)
Effects of currency translation in discontinued operations	0	11
Change in cash and cash equivalents, including discontinued operations	(91,893)	42,506
Cash and cash equivalents, including discontinued operations, at beginning of period	576,645	363,789
Cash and cash equivalents, including discontinued operations, at end of period	484,752	406,295
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	41,415	69,975
Income taxes paid, net	(179)	2,418
Decrease of capital expenditures in Accounts payable or Other current liabilities	(29,800)	(19,052)
Equity AFUDC capitalized in regulated operations plant	2,033	1,353
Continuing Operations
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	41,415	49,759
Income taxes paid, net	(179)	343
Decrease of capital expenditures in Accounts payable or Other current liabilities	(29,800)	(10,600)
Equity AFUDC capitalized in regulated operations plant	2,033	1,353
Discontinued Operations
SUPPLEMENTAL INFORMATION:
Interest paid, net of amounts capitalized	0	20,216
Income taxes paid, net	0	2,075
Decrease of capital expenditures in Accounts payable or Other current liabilities	0	(8,452)
Equity AFUDC capitalized in regulated operations plant	$ 0	$ 0

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Amortization of prior service cost, tax	$ 11	$ 11
Amortization of net actuarial loss, tax	606	226
Regulatory adjustment, tax	$ (477)	$ (152)

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2026	Dec. 31, 2025
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)	72,373,216	72,224,593
Common stock, outstanding (in shares)	72,373,216	72,224,593

Previously Issued Condensed Consolidated Financial Statement (Tables)

3 Months Ended

Mar. 31, 2026

Accounting Changes and Error Corrections [Abstract]

Schedule of Error Corrections and Prior Period Adjustments

The effects of the correction of the errors on the Condensed Consolidated Financial Statements are as follows:


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED BALANCE SHEETS
(In thousands)
(Unaudited)

	March 31, 2025
	As Reported		Adjustments		As Revised



CAPITALIZATION AND LIABILITIES
Retained earnings	$	1,238,775	$	(36,723)	$	1,202,052
Total equity	3,416,872		(36,723)		3,380,149
Total capitalization	6,922,224		(36,723)		6,885,501


Deferred income taxes and investment tax credits, net	857,986		36,723		894,709
Total deferred income taxes and other credits	2,025,235		36,723		2,061,958
Total capitalization and liabilities	$	9,679,467	$	—	$	9,679,467


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
(In thousands)
(Unaudited)

	Three Months Ended March 31, 2025
	As Reported		Adjustments		As Revised
Regulated operations revenues	$	746,416	$	2,100	$	748,516
Operating income	214,979		2,100		217,079
Income before income taxes	179,650		2,100		181,750
Income tax expense	36,708		2,447		39,155
Net income (loss)	$	142,942	$	(347)	$	142,595


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(In thousands)
(Unaudited)

	Three Months Ended March 31, 2025
	As Reported		Adjustments		As Revised
Net income (loss)	$	142,942	$	(347)	$	142,595
Comprehensive income (loss)	$	143,210	$	(347)	$	142,863


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
(In thousands)
(Unaudited)

	Three Month Ended March 31, 2025
	As Reported		Adjustments		As Revised
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	$	142,942	$	(347)	$	142,595
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	37,928		2,447		40,375
Changes in current assets and liabilities:
Accounts receivable, net of allowance	(11,117)		(2,100)		(13,217)
Deferred purchased gas costs	53,865		1,997		55,862
Accounts payable	(44,691)		(1,997)		(46,688)
Net cash provided by operating activities	$	285,832	$	—	$	285,832


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF EQUITY
(In thousands)
(Unaudited)

	As Reported		Adjustments		As Revised


Net income (loss), for the three months ended March 31, 2025	$	142,942	$	(347)	$	142,595
Retained earnings, March 31, 2025	1,238,775		(36,723)		1,202,052
Total Equity, March 31, 2025	$	3,416,872	$	(36,723)	$	3,380,149

Debt (Tables)

3 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

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.


	March 31,				December 31,
	2026				2025
(Thousands of dollars)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Southwest Gas Holdings, Inc. and Southwest Gas Corporation:
Debentures:
8% Series, due August 2026	$	75,000	$	75,813	$	75,000	$	76,388
Medium-term notes, 7.92% series, due June 2027	25,000		25,850		25,000		26,058
Medium-term notes, 6.76% series, due September 2027	7,500		7,679		7,500		7,726
Notes, 5.8%, due December 2027	300,000		306,480		300,000		309,090
Notes, 3.7%, due April 2028	300,000		296,370		300,000		297,450
Notes, 5.45%, due February 2028	300,000		305,730		300,000		307,620
Notes, 2.2%, due June 2030	450,000		409,455		450,000		409,365
Notes, 4.05%, due March 2032	600,000		573,000		600,000		579,540
Notes, 6.1%, due February 2041	125,000		128,913		125,000		130,762
Notes, 4.875%, due October 2043	250,000		215,525		250,000		219,350
Notes, 3.8%, due September 2046	300,000		225,000		300,000		228,180
Notes, 4.15%, due June 2049	300,000		230,160		300,000		237,120
Notes, 3.18%, due August 2051	300,000		194,100		300,000		205,710
Unamortized discount and debt issuance costs	(22,367)				(23,207)
	3,310,133				3,309,293

Industrial development revenue bonds:
Tax-exempt Series A, due December 2028	50,000		50,000		50,000		50,000
2003 Series A, due March 2038	50,000		50,000		50,000		50,000
2008 Series A, due March 2038	50,000		50,000		50,000		50,000
2009 Series A, due December 2039	50,000		50,000		50,000		50,000
Unamortized discount and debt issuance costs	(1,204)				(1,281)
	198,796				198,719
Less: current maturities	75,000				75,000
Southwest Gas Holdings, Inc. and Southwest Gas Corporation total long-term debt, less current maturities	$	3,433,929			$	3,433,012

- 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

Revenue

3 Months Ended

Mar. 31, 2026

Revenue from Contract with Customer [Abstract]

Revenue

Note 3 – Revenue

Southwest Gas’ operating revenues, but not its operating margin, are directly impacted by variability between comparative periods in the cost of natural gas procured for customers as these costs are incorporated in customer rates. When included in rates (for customers except those taking transportation-only service), these costs are passed through to customers generally dollar-for-dollar without markup. Operating margin is a non-GAAP financial measure and should be considered in addition to, not as a substitute for, measures of financial performance prepared in accordance with GAAP. 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 March 31,
(Thousands of dollars)	2026		2025
Residential	$	398,304	$	561,639
Small commercial	88,707		130,365
Large commercial	15,152		21,715
Industrial/other	10,310		13,472
Transportation	30,565		29,566
Revenue from contracts with customers	543,038		756,757
Alternative revenue program revenues	40,145		(12,366)
Other revenues (1)	1,936		2,025
Total Regulated operations revenues(2)	$	585,119	$	746,416

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

(2) The amounts for the three months ended March 31, 2025 differ from Southwest Gas due to the revision discussed in Note 6 - Previously Issued Condensed Consolidated Financial Statement.

As of March 31, 2026, the Company and Southwest had backlog performance obligations through Great Basin, excluding intercompany transactions, totaling $53.5 million through August 31, 2029. Of the current backlog, $11.2 million is expected to be fulfilled within the year ended December 31, 2026, $15.9 million within the year ended December 31, 2027, $15.9 million within the year ended December 31, 2028, and $10.5 million within the year ended December 31, 2029. Under the terms of Great Basin’s current settlement agreement, new rates will become effective no later than September 1, 2029. Accordingly, the Company and Southwest Gas are unable to reasonably estimate performance obligations that may arise beyond September 1, 2029. The backlog consists of firm customer contracts for natural gas distribution services. The current backlog does not reflect any contracts or commitments associated with the potential 2028 Great Basin Expansion project. Seasonal fluctuation may impact the timing of fulfillment as demand for natural gas typically increases during winter months. The Company defines backlog as the aggregate value of signed contracts for which performance obligations remain unsatisfied.

- 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
-Topic 606
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+ Details

Components of Net Periodic Benefit Cost (Tables)

3 Months Ended

Mar. 31, 2026

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 months ended March 31, 2026 and 2025 are presented in the following tables.


	Three Months Ended March 31,
	2026						2025
(Thousands of dollars)	QRP		SERP		PBOP		QRP		SERP		PBOP

Service cost	$	6,467	$	52	$	299	$	6,098	$	58	$	292
Interest cost	16,726		589		835		16,397		596		856
Expected return on plan assets	(22,221)		—		(694)		(22,582)		—		(624)
Amortization of prior service costs	—		—		44		—		—		44
Amortization of net actuarial loss (gain)	2,295		334		(103)		752		270		(78)
Net periodic benefit cost	$	3,267	$	975	$	381	$	665	$	924	$	490

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net income	$ 138,374	$ 109,187
Defined benefit pension plans:
Amortization of prior service cost, net of tax of $11 and $11, respectively	33	33
Amortization of net actuarial loss, net of tax of $606 and $226, respectively	1,920	718
Regulatory adjustment, net of tax of ($477) and ($152), respectively	(1,507)	(483)
Net defined benefit pension plans, net of tax	446	268
Other comprehensive income related to discontinued operations	0	104
Total other comprehensive income, net of tax	446	372
Comprehensive income	138,820	109,559
Comprehensive loss attributable to noncontrolling interests	0	(4,663)
Comprehensive income attributable to Southwest Gas Holdings, Inc.	$ 138,820	$ 114,222

Summary of Significant Accounting Policies - Schedule of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Accounting Policies [Abstract]
Weighted average basic shares (in shares)	72,441,000	72,012,000
Effect of dilutive securities:
Restricted stock units (in shares)	125,000	126,000
Weighted average diluted shares (in shares)	72,566,000	72,138,000
Number of performance share units granted (in shares)	105,000	110,000
Anti-dilutive restricted stock (in shares)		126,000

Previously Issued Condensed Consolidated Financial Statement

3 Months Ended

Mar. 31, 2026

Accounting Changes and Error Corrections [Abstract]

Previously Issued Condensed Consolidated Financial Statement

Note 6 - Previously Issued Condensed Consolidated Financial Statement

In connection with the Company’s 2025 Form 10-K for Southwest Gas, management identified errors in the calculation of the estimated deferred income tax liabilities associated with state income taxes. The issues result from not timely updating estimated apportionment rates to reflect certain events. For Southwest Gas, the errors date back to the formation of Southwest Gas Holdings in 2017, when Southwest Gas and Centuri became wholly-owned subsidiaries of Southwest Gas Holdings. These errors were determined to be not material to any previously issued Southwest Gas financial statements. However, Southwest Gas revised the historical financial statements due to the magnitude of the cumulative effect of the prior year errors. Southwest Gas also revised the historical financial statements to correct other previously identified immaterial errors.

The effects of the correction of the errors on the Condensed Consolidated Financial Statements are as follows:


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED BALANCE SHEETS
(In thousands)
(Unaudited)

	March 31, 2025
	As Reported		Adjustments		As Revised



CAPITALIZATION AND LIABILITIES
Retained earnings	$	1,238,775	$	(36,723)	$	1,202,052
Total equity	3,416,872		(36,723)		3,380,149
Total capitalization	6,922,224		(36,723)		6,885,501


Deferred income taxes and investment tax credits, net	857,986		36,723		894,709
Total deferred income taxes and other credits	2,025,235		36,723		2,061,958
Total capitalization and liabilities	$	9,679,467	$	—	$	9,679,467


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
(In thousands)
(Unaudited)

	Three Months Ended March 31, 2025
	As Reported		Adjustments		As Revised
Regulated operations revenues	$	746,416	$	2,100	$	748,516
Operating income	214,979		2,100		217,079
Income before income taxes	179,650		2,100		181,750
Income tax expense	36,708		2,447		39,155
Net income (loss)	$	142,942	$	(347)	$	142,595


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(In thousands)
(Unaudited)

	Three Months Ended March 31, 2025
	As Reported		Adjustments		As Revised
Net income (loss)	$	142,942	$	(347)	$	142,595
Comprehensive income (loss)	$	143,210	$	(347)	$	142,863


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
(In thousands)
(Unaudited)

	Three Month Ended March 31, 2025
	As Reported		Adjustments		As Revised
CASH FLOW FROM OPERATING ACTIVITIES:
Net income (loss)	$	142,942	$	(347)	$	142,595
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	37,928		2,447		40,375
Changes in current assets and liabilities:
Accounts receivable, net of allowance	(11,117)		(2,100)		(13,217)
Deferred purchased gas costs	53,865		1,997		55,862
Accounts payable	(44,691)		(1,997)		(46,688)
Net cash provided by operating activities	$	285,832	$	—	$	285,832


SOUTHWEST GAS CORPORATION AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF EQUITY
(In thousands)
(Unaudited)

	As Reported		Adjustments		As Revised


Net income (loss), for the three months ended March 31, 2025	$	142,942	$	(347)	$	142,595
Retained earnings, March 31, 2025	1,238,775		(36,723)		1,202,052
Total Equity, March 31, 2025	$	3,416,872	$	(36,723)	$	3,380,149