v3.26.1
Employee Benefit Plans
 3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Employee Benefit Plans EMPLOYEE BENEFIT PLANS
POSTRETIREMENT BENEFITS–Eligible employees of Basin Electric, Dakota Gas, and MLC who are retiring may elect to continue medical and dental benefits by paying premiums to continue participating in the current employee plan. Coteau also maintains medical care and life insurance plans which provide benefits to eligible retired employees.
Components of net periodic postretirement benefit expense (income) for the three months ended March 31, 2026 and 2025 were as follows:
Basin Electric and
Subsidiaries		Coteau
2026202520262025
(In thousands)
Service cost$319 $292 $3 $5 
Interest cost258 233 13 16 
Amortization of prior service cost58 58 — — 
Amortization of net actuarial gain(412)(459)(110)(169)
Net periodic expense (income)$223 $124 $(94)$(148)
Basin Electric, Dakota Gas, and MLC made contributions (withdrawals) of $768,000 and $(163,000) to (from) the postretirement benefit plans during the three months ended March 31, 2026 and 2025, respectively.
DEFINED BENEFIT PLANS
NRECA RS PLAN–Pension benefits for Basin Electric and Dakota Gas employees participating in the pension plan are provided through participation in the National Rural Electric Cooperative Association (NRECA) Retirement Security Plan (RS Plan) which is a defined benefit pension plan qualified under Section 401 and tax-exempt under Section 501(a) of the Internal Revenue code. It is a multiemployer plan under GAAP.
Pension costs charged to expense for the three months ended March 31, 2026 and 2025 were $9.6 million and $9.5 million, respectively.
BCS AND COTEAU PLANS–BCS’s former United Mine Workers of America employees are covered under a defined benefit plan which is funded by BCS. Substantially all of Coteau’s salaried employees hired prior to January 1, 2000, participate in the Coteau Pension Plan (the Plan), a noncontributory defined benefit plan sponsored by NACoal. In October 2025, Coteau terminated the Plan and settled all future obligations by transferring the remaining benefit obligations to a third-party insurance company.
Components of net periodic pension expense (income) for the three months ended March 31, 2026 and 2025 were as follows:
BCSCoteau
2026202520262025
(In thousands)
Interest cost$32 $31 $— $904 
Expected return on assets(34)(35)— (1,027)
Amortization of net actuarial loss12 16 — — 
Settlements— — 45 — 
Net periodic expense (income)$10 $12 $45 $(123)
BCS did not make any contributions to the defined benefit plan during the three months ended March 31, 2026. BCS and Coteau did not make any contributions to the defined benefit plans for the three months ended March 31, 2025.