Employee Benefit Plans

401(k) Plan

The Company maintains defined contribution and profit sharing plans in conformity with the provisions of section 401(k) of the Internal Revenue Code. The Columbia Bank 401(k) and Profit Sharing Plan (the “401(k) Plan”), permits Columbia Bank employees who are at least 18 years of age to contribute up to 75% of their eligible compensation to the 401(k) Plan starting on the first day of the month following their hire date. On a per pay period basis the Company is required to match 50% of employee contributions up to 3% of each employee’s eligible compensation. The Company contributed $3.3 million during 2018, $2.7 million during 2017, and $2.4 million during 2016, in matching funds to the 401(k) Plan. Additionally, as determined annually by the board of directors of the Company, the 401(k) Plan provides for a non-matching discretionary profit sharing contribution. The Company’s discretionary profit sharing contributions were $7.0 million during 2018, $5.7 million during 2017 and $5.1 million during 2016.

Employee Stock Purchase Plan

The Company maintains an “Employee Stock Purchase Plan” (the “ESP Plan”) in which substantially all employees of the Company are eligible to participate. The ESP Plan provides participants the opportunity to purchase common stock of the Company at a discounted price. Under the ESP Plan, participants can purchase common stock of the Company for 90% of the lowest price on either the first or last day in each of two six month look-back periods. The look-back periods are January 1st through June 30th and July 1st through December 31st of each calendar year. The 10% discount is recognized by the Company as compensation expense and does not have a material impact on net income or earnings per common share. Participants of the ESP Plan purchased 50,750 shares for $2.0 million in 2018, 38,387 shares for $1.5 million in 2017 and 50,116 shares for $1.8 million in 2016. At December 31, 2018 there were 360,357 shares available for purchase under the ESP Plan.

Supplemental Compensation Plan

The Company maintains supplemental compensation arrangements (“Unit Plans”) to provide benefits for certain employees. The Unit Plans generally vest over a 10 year period and provide a fixed annual benefit over the subsequent 10 year period. At December 31, 2018 and 2017, the liability associated with these plans was $4.2 million and $4.6 million, respectively. Expense associated with these plans for the years ended December 31, 2018, 2017 and 2016 was $337 thousand, $452 thousand and $467 thousand, respectively.

Supplemental Executive Retirement Plan

The Company maintains a supplemental executive retirement plan (the “SERP”), a nonqualified deferred compensation plan that provides retirement benefits to certain highly compensated executives. The SERP is unsecured and unfunded and there are no program assets. The SERP projected benefit obligation, which represents the vested net present value of future payments to individuals under the plan is accrued over the estimated remaining term of employment of the participants and has been determined by actuarial valuation using a discount rate of 4.30% for 2018 and 3.80% for 2017. Additional assumptions and features of the plan are a normal retirement age of 65 and a 2% annual cost of living benefit adjustment. The projected benefit obligation is included in “Other liabilities” on the Consolidated Balance Sheets.

The following table reconciles the accumulated liability for the projected benefit obligation:



	December 31,
	2018			2017
	(in thousands)
Balance, beginning of year	$	20,553		$	26,263
Change in actuarial gain	(31		)	(6,453		)
Plan amendments	—			148
Benefit expense	1,701			1,600
Benefit payments	(936		)	(1,005		)
Balance, end of year	$	21,287		$	20,553

The benefits expected to be paid in conjunction with the SERP are presented in the following table:



	Years Ending December 31,
	(in thousands)
2019	$	963
2020	1,971
2021	2,095
2022	1,135
2023	1,236
2024 through 2028	8,236
Total	$	15,636