12.	SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN:

On March 18, 2010, the Compensation Committee and the Board of Directors of the Company approved and adopted the Universal Display Corporation Supplemental Executive Retirement Plan (SERP), effective as of April 1, 2010. On March 3, 2015, the Compensation Committee and the Board of Directors amended the SERP to include salary and bonus as part of the plan. Prior to this amendment, the SERP benefit did not take into account any bonuses. This change increased the liability for certain participants in the SERP. The purpose of the SERP, which is unfunded, is to provide certain of the Company’s key employees with supplemental retirement benefits following a cessation of their employment and to encourage their continued employment with the Company. As of June 30, 2018, there were seven participants in the SERP.

The Company records amounts relating to the SERP based on calculations that incorporate various actuarial and other assumptions, including discount rates, rate of compensation increases, retirement dates and life expectancies. The net periodic costs are recognized as employees render the services necessary to earn the SERP benefits.

The components of net periodic pension cost were as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Service cost	$	325	$	302	$	650	$	603
Interest cost		262		252		524		494
Amortization of prior service cost		421		415		842		830
Amortization of loss		118		114		236		161
Total net periodic benefit cost	$	1,126	$	1,083	$	2,252	$	2,088