
	Period of	June 30, 2026				December 31, 2025
(in thousands)	Recovery/Refund	Current		Long-Term		Current		Long-Term

Regulatory Assets
Pension and Other Postretirement Benefit Plans1	Various	$	2,765	$	73,141	$	2,765	$	72,762
Alternative Revenue Program Riders2	Up to 2 years	9,193		3,489		7,834		1,036
Deferred Income Taxes1	Asset lives	—		8,907		—		9,007
Fuel Clause Adjustments1	Up to 1 year	4,528		—		6,558		—
Derivative Instruments1	Up to 2 years	2,494		915		2,717		—
Other1	Various	937		5,391		563		3,257
Total Regulatory Assets		$	19,917	$	91,843	$	20,437	$	86,062
Regulatory Liabilities
Deferred Income Taxes	Asset lives	$	—	$	122,921	$	—	$	125,413
Plant Removal Obligations	Asset lives	—		127,059		—		130,686
Fuel Clause Adjustments	Up to 1 year	11,585		—		1,231		—
Alternative Revenue Program Riders	Up to 1 year	11,469		—		9,961		—
North Dakota PTC Refunds	Asset lives	—		38,123		—		29,169
Pension and Other Postretirement Benefit Plans	Various	3,174		10,109		3,174		9,187



Other	Various	2,602		2,508		2,234		2,943
Total Regulatory Liabilities		$	28,830	$	300,720	$	16,600	$	297,398

1Costs subject to recovery without a rate of return.
2Amounts eligible for recovery include an incentive or rate of return.

On June 4, 2025, Otter Tail Power Company (OTP) filed a request with the South Dakota Public Utilities Commission (SDPUC) for an increase in revenue recoverable under general rates in South Dakota. In its filing, OTP requested a net increase in annual revenue of $5.7 million, or 12.50%, based on an allowed rate of return on rate base of 8.29%. Interim rates went into effect on December 1, 2025, and were subject to potential refund until the finalization of the rate case.

On March 10, 2026, the SDPUC approved a settlement agreement between OTP and the commission staff in the general rate case. The key provisions of the order included a net increase in annual revenue of $3.3 million, or 7.7%, based on a return on rate base of 7.09%. Through the settlement of the case, the parties also agreed to a moratorium on increases to base rates until December 1, 2029, with certain exceptions. New base rates in South Dakota went into effect on April 1, 2026, and interim rate refunds totaling $0.8 million were refunded to customers during the three months ended June 30, 2026.

On October 31, 2025, OTP filed a request with the Minnesota Public Utilities Commission (MPUC) for an increase in revenue recoverable under general rates in Minnesota. In its filing, OTP requested a net increase in annual revenue of $44.8 million, or 17.7%, based on an allowed rate of return on rate base of 7.92% and an allowed return on equity (ROE) of 10.65% on an equity ratio of 53.5% of total capital. The request includes, among other items, accelerated recovery of the remaining investment of the jurisdictionally allocated share of Coyote Station, which has a $4.3 million annual impact. The request for accelerated recovery is driven by the MPUC’s order in OTP’s most recent Integrated Resource Plan (IRP) to discontinue serving Minnesota customers with capacity and energy from Coyote Station by December 2031. If this part of the request is granted, we anticipate the amounts collected would be deferred and recognized over the remaining estimated useful life of the plant, which extends until 2041. The filing also included an interim rate request for a net increase in annual revenue of $31.8 million, or 12.6%.

On December 23, 2025, the MPUC approved the interim rate request with a modification to exclude the impact of the accelerated recovery of the remaining investment of the jurisdictionally allocated share of Coyote Station from interim rates. The resulting interim net increase in annual revenue is $28.6 million, or 11.3%. Interim rates went into effect on January 1, 2026, and are subject to potential refund until the finalization of the rate case.