Retirement Plans and Other Postretirement Benefits

3 Months Ended

Mar. 31, 2026

Retirement Benefits [Abstract]

Retirement Plans and Other Postretirement Benefits

Retirement Plans and Other Postretirement Benefits

Pinnacle West sponsors a qualified defined benefit and account balance pension plan, a non-qualified supplemental excess benefit retirement plan, and other postretirement benefit plans for the employees of Pinnacle West and our subsidiaries.  The other postretirement benefit plans include a group life and medical plan and a post-65 retiree health reimbursement arrangement (“HRA”). Pinnacle West uses a December 31 measurement date each year for its pension and other postretirement benefit plans.  The market-related value of our plan assets is their fair value at the measurement date.

The following table provides detail of the plans’ net periodic benefit costs and the portion of these costs charged to expense (including administrative costs and excluding amounts capitalized as overhead construction or billed to electric plant participants) (dollars in thousands):

	Pension Plans				Other Benefits Plans
	Three Months Ended March 31,				Three Months Ended March 31,
	2026		2025		2026		2025
Service cost-benefits earned during the period	$	12,099	$	10,949	$	2,237	$	1,982
Non-service costs (credits):
Interest cost on benefit obligation	37,612		38,976		4,979		5,102
Expected return on plan assets	(44,096)		(44,547)		(12,719)		(12,142)
Amortization of:
Prior service cost (credit)	151		—		—		(1,265)
Net actuarial loss (gain)	11,153		12,118		(2,700)		(2,899)
Net periodic benefit costs (credits)	$	16,919	$	17,496	$	(8,203)	$	(9,222)
Portion of costs (credits) charged to expense	$	9,518	$	10,461	$	(6,509)	$	(6,873)

Contributions

Future year contribution amounts are dependent on plan asset performance and plan actuarial assumptions. The expected minimum required cash contributions for the pension plan are zero for the next three years and we do not expect to make any voluntary contributions in 2026, 2027 or 2028; however, we continue to evaluate and assess our ongoing contribution strategy. Regarding contributions to our other postretirement benefit plan, we have not made a contribution year-to-date in 2026 and do not expect to make any contributions in 2026, 2027 or 2028. The Company was reimbursed $23 million in April 2026 for a prior year’s retiree medical claims from the other postretirement benefit plan trust assets.