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v3.26.1

Pension and Other Postretirement Plans | 6 Months Ended
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Jun. 30, 2026
Retirement Benefits [Abstract] |
Pension and Other Postretirement Plans | Pensi on and Other Postretirement Plans - MGE Energy and MGE. MGE maintains qualified and nonqualified pension plans, health care, and life insurance benefits and defined contribution 401(k) benefit plans for its employees and retirees. The components of net periodic benefit cost, other than the service cost component, are recorded in "Other income, net" on the consolidated statements of income. The service cost component is recorded in "Other operations and maintenance" on the consolidated statements of income. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net periodic benefit costs are recovered and when costs are recognized. The following table presents the components of net periodic benefit costs recognized.
|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
(In thousands) |  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Pension Benefits |  |  |  |  |  |  |  |  |  |  |  |
Components of net periodic benefit cost: |  |  |  |  |  |  |  |  |  |  |  |
Service cost |  | $ | 583 |  |  | $ | 655 |  |  | $ | 1,202 |  |  | $ | 1,306 |
Interest cost |  |  | 4,062 |  |  |  | 4,313 |  |  |  | 8,073 |  |  |  | 8,569 |
Expected return on assets |  |  | (7,790 | ) |  |  | (7,246 | ) |  |  | (15,526 | ) |  |  | (14,507 | )
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |
Actuarial loss |  |  | 59 |  |  |  | 102 |  |  |  | 103 |  |  |  | 150 |
Net periodic benefit (credit) cost |  | $ | (3,086 | ) |  | $ | (2,176 | ) |  | $ | (6,148 | ) |  | $ | (4,482 | )
Postretirement Benefits |  |  |  |  |  |  |  |  |  |  |  |
Components of net periodic benefit cost: |  |  |  |  |  |  |  |  |  |  |  |
Service cost |  | $ | 177 |  |  | $ | 188 |  |  | $ | 352 |  |  | $ | 371 |
Interest cost |  |  | 677 |  |  |  | 754 |  |  |  | 1,359 |  |  |  | 1,514 |
Expected return on assets |  |  | (712 | ) |  |  | (634 | ) |  |  | (1,419 | ) |  |  | (1,358 | )
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |
Transition obligation |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 1 |
Actuarial gain |  |  | (208 | ) |  |  | (173 | ) |  |  | (389 | ) |  |  | (321 | )
Net periodic benefit (credit) cost |  | $ | (66 | ) |  | $ | 135 |  |  | $ | (97 | ) |  | $ | 207 |
As approved by the PSCW, MGE is allowed to defer differences between actual employee benefit plan costs and costs reflected in current rates. The deferred costs may be recovered or refunded in MGE's next rate filing. In 2026, MGE is refunding over-collected costs from previous years. During the three and six months ended June 30, 2025, MGE recovered $0.1 million and $0.7 million, respectively. These costs have not been reflected in the table above.

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