
	March 31, 2026
	Current		Noncurrent		Total
	(Thousands of dollars)
Under-recovered purchased-gas costs	$	2,261	$	—	$	2,261
Pension and postemployment benefit costs, net	10,187		217,257		227,444
Reacquired debt costs	723		1,085		1,808
MGP remediation costs	1,000		29,592		30,592

WNA	25,165		—		25,165
Customer credit deferrals	14,779		1,081		15,860
Other, net	7,372		3,033		10,405
Total regulatory assets	61,487		252,048		313,535
Income tax rate changes	—		(432,690)		(432,690)
Over-recovered purchased-gas costs	(18,378)		—		(18,378)
Ad-valorem tax	(1,553)		—		(1,553)
Other	(1,707)		(8,351)		(10,058)
Total regulatory liabilities	(21,638)		(441,041)		(462,679)
Net regulatory assets and liabilities	$	39,849	$	(188,993)	$	(149,144)


	December 31, 2025
	Current		Noncurrent		Total
	(Thousands of dollars)

Under-recovered purchased-gas costs	$	10,692	$	—	$	10,692
Pension and postemployment benefit costs, net	10,929		221,809		232,738
Reacquired debt costs	723		1,266		1,989
MGP remediation costs	1,000		29,105		30,105

WNA	19,175		—		19,175
Customer credit deferrals	2,953		1,091		4,044
Other, net	4,032		2,954		6,986
Total regulatory assets	49,504		256,225		305,729

Income tax rate changes	—		(444,986)		(444,986)
Over-recovered purchased-gas costs	(56,876)		—		(56,876)
Ad-valorem tax	(165)		—		(165)
Other	(236)		(6,634)		(6,870)
Total regulatory liabilities	(57,277)		(451,620)		(508,897)
Net regulatory assets and liabilities	$	(7,773)	$	(195,395)	$	(203,168)

Regulatory assets in our consolidated balance sheets, as authorized by various regulatory authorities, are probable of recovery. Base rates and certain riders are designed to provide a recovery of costs during the period such rates are in effect, but do not generally provide for a return on investment for amounts we have deferred as regulatory assets. All of our regulatory assets are subject to review by the respective regulatory authorities during future regulatory proceedings.

Other regulatory assets and liabilities - Purchased-gas costs represent the natural gas costs that have been over- or under-recovered from customers through the purchased-gas cost adjustment mechanisms, and includes natural gas utilized in our operations and premiums paid and any cash settlements received from our purchased natural gas call options or swap agreements.

The OCC, KCC, and regulatory authorities in Texas have approved the recovery of pension costs and other postemployment benefits costs through rates for Oklahoma Natural Gas, Kansas Gas Service, and Texas Gas Service, respectively. The costs recovered through rates are based on the net periodic benefit cost for defined benefit pension and other postemployment costs. Differences, if any, between the net periodic benefit cost (credit), net of deferrals, and the amount recovered through rates are reflected in earnings. We historically have recovered defined benefit pension and other postemployment benefit costs through

rates. We believe it is probable that regulators will continue to include the net periodic pension and other postemployment benefit costs in our cost of service.

Ad-valorem tax represents the difference in Kansas Gas Service’s taxes incurred each year above or below the amount approved in base rates. This difference is deferred as a regulatory asset or liability for a 12-month period. Kansas Gas Service then applies an adjustment to customers’ bills to refund the over-collected revenue or bill the under-collected revenue over the subsequent 12 months.

Weather normalization represents revenue over- or under-recovered through the WNA rider in Kansas. This amount is deferred as a regulatory asset or liability for a 12-month period. Kansas Gas Service then applies an adjustment to customers’ bills for 12 months to refund the over-collected revenue or bill the under-collected revenue.

The customer credit deferrals and the noncurrent regulatory liability for income tax rate changes represent deferral of the effects of enacted federal and state income tax rate changes on our ADIT and the effects of these changes on our rates.

Recovery through rates resulted in amortization of regulatory assets that was immaterial for the three months ended March 31, 2026, and approximately $6.0 million for the three months ended March 31, 2025.