The Company provides a qualified defined benefit pension to eligible employees and retirees, other post-retirement health and life insurance benefits to certain retirees, an unfunded supplemental pension plan for certain key executives, and an unfunded stock balance plan for certain of its nonemployee directors. Using a measurement date of December 31, the following table shows the funded status of the Company's plans reconciled with amounts reported in the Company's consolidated statements of condition:

The benefit obligation for the defined benefit pension plan was $170.8 million and $145.4 million as of December 31, 2020 and 2019, respectively, and the fair value of plan assets as of December 31, 2020 and 2019 was $272.6 million and $227.3 million, respectively. The defined benefit pension plan was amended effective December 31, 2020 to transfer certain obligations from the Company’s deferred compensation plan and Restoration Plan (as defined below) into the qualified defined benefit pension plan. Effective December 31, 2020, the Steuben Trust Company Pension Plan was merged into the Community Bank System, Inc. Pension Plan and the combined plan was revalued resulting in an additional unamortized actuarial gain of approximately $1.1 million, due primarily to a gain on plan assets as of the valuation date.

The Company has unfunded supplemental pension plans for certain key active and retired executives. The projected benefit obligation for the unfunded supplemental pension plan for certain key executives was $19.6 million and $16.4 million for 2020 and 2019, respectively. The Company also has an unfunded stock balance plan for certain of its nonemployee directors. The projected benefit obligation for the unfunded stock balance plan was $0.1 million for 2020 and 2019. The plan was frozen effective December 31, 2009.

Effective June 1, 2018, the Company adopted the Community Bank System, Inc. Restoration Plan (“Restoration Plan”). The Restoration Plan is a non-qualified deferred compensation plan for certain employees whose benefits under tax-qualified retirement plans are restricted by the Internal Revenue Code Section 401(a)(17) limitation on compensation. Adoption of the plan resulted in an unfunded initial projected benefit obligation of approximately $0.8 million. The Restoration Plan was amended effective December 31, 2020 to transfer certain obligations into the Company’s qualified defined benefit pension plan. The projected benefit obligation for the unfunded Restoration Plan was $0.03 million for 2020 and $0.3 million for 2019, respectively.

Effective December 31, 2009, the Company terminated its post-retirement medical program for current and future employees. Remaining plan participants will include only existing retirees as of December 31, 2010. This change was accounted for as a negative plan amendment and a $3.5 million, net of income taxes, benefit for prior service was recognized in AOCI in 2009. This negative plan amendment is being amortized over the expected benefit utilization period of remaining plan participants.

Amounts recognized in accumulated other comprehensive income, net of tax, for the year ended December 31, are as follows:

The estimated costs, net of tax, that will be amortized from accumulated other comprehensive (income) loss into net periodic (income) cost over the next fiscal year are as follows:

The weighted-average assumptions used to determine the benefit obligations as of December 31 are as follows:

Prior service costs in which all or almost all of the plan’s participants are fully eligible for benefits under the plan are amortized on a straight-line basis over the expected future working years of all active plan participants. Unrecognized gains or losses are amortized using the “corridor approach”, which is the minimum amortization required. Under the corridor approach, the net gain or loss in excess of 10 percent of the greater of the projected benefit obligation or the market-related value of the assets is amortized on a straight-line basis over the expected future working years of all active plan participants.

The weighted-average assumptions used to determine the net periodic pension cost for the years ended December 31 are as follows:

The amount of benefit payments that are expected to be paid over the next ten years are as follows:

The payments reflect future service and are based on various assumptions including retirement age and form of payment (lump-sum versus annuity). Actual results may differ from these estimates.

The assumed discount rate is used to reflect the time value of future benefit obligations. The discount rate was determined based upon the yield on high-quality fixed income investments expected to be available during the period to maturity of the pension benefits. This rate is sensitive to changes in interest rates. A decrease in the discount rate would increase the Company’s obligation and future expense while an increase would have the opposite effect. The expected long-term rate of return was estimated by taking into consideration asset allocation, reviewing historical returns on the type of assets held and current economic factors. Based on the Company’s anticipation of future experience under the defined benefit pension plan, the mortality tables used to determine future benefit obligations under the plan were updated as of December 31, 2020 to the sex-distinct Pri-2012 Mortality Tables for employees, healthy annuitants and contingent survivors, adjusted for mortality improvements using Scale MP-2020 mortality improvement scale on a generational basis. The appropriateness of the assumptions are reviewed annually.

The investment objective for the defined benefit pension plan is to achieve an average annual total return over a five-year period equal to the assumed rate of return used in the actuarial calculations. At a minimum performance level, the portfolio should earn the return obtainable on high quality intermediate-term bonds. The Company’s perspective regarding portfolio assets combines both preservation of capital and moderate risk-taking. Asset allocation favors fixed income securities, with a target allocation of approximately 60% equity securities and 40% fixed income securities and money market funds. Due to the volatility in the market, the target allocation is not always desirable and asset allocations will fluctuate between acceptable ranges. Prohibited transactions include purchase of securities on margin, uncovered call options, and short sale transactions.

The fair values of the Company’s defined benefit pension plan assets at December 31, 2020 by asset category are as follows:

The fair values of the Company’s defined benefit pension plan assets at December 31, 2019 by asset category are as follows:

The valuation techniques used to measure fair value for the items in the table above are as follows:

The Company makes contributions to its funded qualified pension plan as required by government regulation or as deemed appropriate by management after considering the fair value of plan assets, expected return on such assets, and the value of the accumulated benefit obligation. The Company made a $3.5 million contribution to the Steuben Trust Company Pension Plan in 2020. The Company made a $3.9 million and $7.3 million contribution to its defined benefit pension plan in 2020 and 2019, respectively. The Company funds the payment of benefit obligations for the supplemental pension and post-retirement plans because such plans do not hold assets for investment.

401(k) Employee Stock Ownership Plan

The Company has a 401(k) Employee Stock Ownership Plan in which employees can contribute from 1% to 90% of eligible compensation, with the first 3% being eligible for a 100% matching contribution in the form of Company common stock and the next 3% being eligible for a 50% matching contributions in the form of Company common stock. The expense recognized under this plan for the years ended December 31, 2020, 2019 and 2018 was $6.3 million, $6.1 million, and $5.9 million, respectively. Effective January 1, 2010, the defined benefit pension plan was modified to a new plan design that includes an interest credit contribution to be made to the 401(k) plan. The expense recognized for this interest credit contribution for the years ended December 31, 2020, 2019, and 2018 was $0.9 million, $1.1 million, and $0.9 million, respectively.

The Company acquired The National Union Bank of Kinderhook 401(k) Savings Plan with the Kinderhook acquisition and The Steuben Trust Company 401(k) Plan with the Steuben acquisition. Effective November 9, 2020 and January 1, 2021, The National Union Bank of Kinderhook 401(k) Savings Plan and The Steuben Trust Company 401(k) Plan were merged into and became part of the Community Bank System, Inc. 401(k) Employee Stock Ownership Plan, respectively.

Other Deferred Compensation Arrangements

In addition to the supplemental pension plans for certain executives, the Company has nonqualified deferred compensation arrangements for several former directors, officers and key employees. All benefits provided under these plans are unfunded and payments to plan participants are made by the Company. At December 31, 2020 and 2019, the Company has recorded a liability of $5.4 million and $2.6 million, respectively. The expense recognized under these plans for the years ended December 31, 2020, 2019, and 2018 was approximately $0.4 million, $0.2 million, and $0.08 million, respectively.

Deferred Compensation Plans for Directors

Directors of the Company may defer all or a portion of their director fees under the Deferred Compensation Plan for Directors. Under this plan, there is a separate account for each participating director which is credited with the amount of shares that could have been purchased with the director’s fees as well as any dividends on such shares. On the distribution date, the director will receive common stock equal to the accumulated share balance in their account. As of December 31, 2020 and 2019, there were 141,655 and 151,519 shares credited to the participants’ accounts, for which a liability of $4.8 million and $4.9 million was accrued, respectively. The expense recognized under the plan for the years ended December 31, 2020, 2019 and 2018, was $0.2 million, $0.2 million, and $0.2 million, respectively.

The Company acquired deferred compensation plans for certain non-employee directors and trustees of Merchants. Under the terms of these acquired deferred compensation plans, participating directors could elect to have all, or a specified percentage, of their Merchants director’s fees for a given year paid in the form of cash or deferred in the form of restricted shares of Merchants’ common stock. Directors who elected to have their compensation deferred were credited with a number of shares of Merchants’ common stock equal in value to the amount of fees deferred. These shares were converted to shares of Company stock in connection with the acquisition and are held in a rabbi trust. The shares held in the rabbi trust are considered outstanding for purposes of computing earnings per share. The participating director may not sell, transfer or otherwise dispose of these shares prior to distribution. With respect to shares of common stock issued or otherwise transferred to a participating director, the participating director has the right to receive dividends or other distributions thereon.