Retirement Plans

The Corporation has a noncontributory defined benefit retirement plan (the Retirement Account Plan (“RAP”)) covering substantially all employees who meet participation requirements. The benefits are based primarily on years of service and the employee’s compensation paid. Employees of acquired entities generally participate in the RAP after consummation of the business combinations. Any retirement plans of acquired entities are typically merged into the RAP after completion of the mergers, and credit is usually given to employees for years of service at the acquired institution for vesting and eligibility purposes.

The Corporation also provides legacy healthcare access to a limited group of retired employees from a previous acquisition in the Postretirement Plan. There are no other active retiree healthcare plans.

Bank Mutual was acquired on February 1, 2018. The Bank Mutual Pension Plan has not yet been merged into the Corporation's Retirement Account Plan. However, Bank Mutual's Postretirement Plan was merged into the Corporation's Postretirement Plan during the first quarter of 2018.

The components of net periodic benefit cost for the RAP, Bank Mutual Pension Plan, and \Postretirement Plan for three months ended March 31, 2018 and 2017 were as follows.



	Three Months Ended March 31,
	2018			2017
	($ in Thousands)
Components of Net Periodic Benefit Cost
RAP
Service cost	$	1,893		$	1,781
Interest cost	1,660			1,756
Expected return on plan assets	(4,755		)	(4,881		)
Amortization of prior service cost	(19		)	(19		)
Amortization of actuarial loss	463			488
Total net pension cost	$	(759	)	$	(875	)
Bank Mutual Pension Plan ^(a)
Interest cost	$	433		N/A
Expected return on plan assets	(532		)	N/A
Total net pension cost	$	(99	)	N/A
Postretirement Plan ^(b)
Interest cost	$	26		$	24
Amortization of prior service cost	(19		)	(19		)
Amortization of actuarial loss	2			—
Total net periodic benefit cost	$	9		$	5


(a)	The reported figures for first quarter 2018 only include two months of expense due to the timing of the Bank Mutual acquisition. See Note 2 for additional information on the Bank Mutual acquisition.


(b)	The portion of the Postretirement Plan attributed to Bank Mutual's Postretirement Plan only includes two months of expense due to the timing of the Bank Mutual acquisition. See Note 2 for additional information on the Bank Mutual acquisition.

The components of net periodic benefit cost other than the service cost component are included in the line item "other" of noninterest expense in the Consolidated Statements of Income.