EMPLOYEE BENEFIT PLANS

We maintain a qualified defined benefit pension plan (“Pension Plan”) and a nonqualified supplemental defined benefit pension plan (“Supplemental Pension Plan”) covering certain employees whose hire date occurred before April 1, 1994.

The weighted-average assumptions used to determine net periodic pension cost for our plans were as follows:



	2015		2014
Discount rate	3.3	%	5.0	%
Rate of increase in compensation levels	2.8	%	3.0	%
Expected long-term rate of return	5.2	%	6.0	%

The components of combined net periodic pension cost were as follows:



	Third Quarter						Year-to-Date
(In thousands)	2015			2014			2015			2014
Service cost - benefits earned in the period	$	512		$	489		$	1,536		$	1,463
Interest cost on projected benefit obligation	594			799			1,781			2,413
Expected investment return on plan assets	(653		)	(804		)	(1,960		)	(2,414		)
Amortization of actuarial loss	502			380			1,507			1,123
Amortization of prior service cost	1			(9		)	4			(26		)
Curtailment loss	192			—			192			—
Settlement loss	1,363			164			1,363			164
Net periodic pension cost	$	2,511		$	1,019		$	4,423		$	2,723

From time to time, we consider the financial benefits, such as reduced regulatory fees and income tax deductions, of making a voluntary contribution to the Pension Plan. During the third quarter of 2015, we made a voluntary contribution of $10.7 million to the Pension Plan. We currently expect no required contributions to the Pension Plan during the fourth quarter of 2015. We will contribute to the nonqualified supplemental defined benefit pension plan as benefits are paid to plan participants, if any, because the nonqualified plan is not a funded plan.

On October 31, 2015, our Board of Directors approved amendments to freeze benefits and terminate the Pension Plan. The Pension Plan will discontinue accruing benefits on December 31, 2015 and the termination will be effective January 31, 2016. As a result of executing the Pension Plan termination amendment, we recorded a curtailment loss, in our income statement, of $0.2 million to immediately recognize all unrecognized past service credits. Additionally, the pension liability and other comprehensive loss were recalculated to reflect the elimination of future compensation increases, which resulted in a decrease of $6.3 million, before tax, during the third quarter of 2015. Typically, the actuarial assumptions used to calculate pension costs are reviewed annually. In light of the amendment to terminate the Pension Plan, the assumptions used to calculate the net period pension costs and the projected benefit obligation were reviewed during the third quarter of 2015. The impact of the change in actuarial assumptions was an increase to our pension liability and other comprehensive loss of $2.8 million, before tax.

It is expected to take 15 to 24 months from the date of the approved amendment to terminate the Pension Plan to complete the termination. The pension liability will be settled through either lump sum payments or purchased annuities. Currently, there is not enough information available to determine the ultimate charge for the termination. At October 31, 2015, there were approximately 800 active participants in the Pension Plan and approximately 650 terminated vested participants. The terminated vested participants can elect to begin to receive benefits at any point in the future, while the active participants will be given the opportunity to receive a lump sum at some point during 2016. All remaining participants in the Pension Plan after the lump sum distributions are completed will have their benefits placed with an annuity provider at the termination distribution date.

Subsequent to October 31, 2015, we communicated the approved amendments to the participants of the Pension Plan. Within this communication, we informed Pension Plan participants that we would provide for a one-time transition benefit to participants who were actively employed on December 31, 2015. We estimate the cost of this one-time transition benefit will range from approximately $6.5 million to $7.5 million, and we will incur the charge in the fourth quarter of 2015.

Lastly, on December 2, 2015, our Board of Directors approved amendments to freeze benefits and terminate the Supplemental Pension Plan. The Supplemental Pension Plan will discontinue accruing benefits on December 31, 2015 and the termination will be effective December 31, 2015. We anticipate the charge associated with the curtailment of the Supplemental Pension Plan will be immaterial.