Commencing with the 2020 equity award, the Company modified the type of equity granted to certain employees to align long-term compensation with Company performance. Under the new structure, the Company continued to issue RSUs; however, RSUs will now vest ratably over three years rather than four years. The Company further replaced stock options with PSUs which will cliff vest at the end of three years. PSUs have performance metrics for which threshold, target, and maximum parameters are established at the time of the grant. The performance metrics are used to calculate the number of shares that will be issuable when the awards vest, which may range from zero to 200% of the target amounts. At the end of each three year performance period, the number of shares that vest will depend on the results achieved against the pre-established performance metrics. The Company recognizes compensation expense for RSUs and PSUs on a straight-line basis over the vesting period; however, compensation expense related to certain PSUs are subject to adjustment on performance relative to the established targets. Furthermore, effective with the 2020 grant, RSUs and PSUs will accrue dividend equivalents prior to vesting, which will be paid out only in respect to shares that actually vest.

On February 25, 2020, the Company’s 2010 Plan expired by its terms. On May 14, 2020, the Company’s shareholders approved the 2020 Plan which provides for the issuance of up to 3.0 million shares of the Company’s Class A common stock (of which approximately 3.0 million shares remain available for future issuance as of September 30, 2020), plus additional shares of Class A common stock (a) subject to awards granted under the 2010 Plan that may become available for issuance or reissuance, as applicable, under the 2020 Plan if such awards are forfeited or are settled in cash or otherwise expire or terminate without the delivery of the shares or (b) which become issuable under the 2020 Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without the receipt of consideration which results in an increase in the number of outstanding shares of Class A common stock.

The Company records compensation expense for employee stock options based on the estimated fair value of the options on the date of grant using the Black-Scholes option-pricing model with the assumptions included in the table below. The Company uses a combination of historical data and historical volatility to establish the expected volatility, as well as to estimate the expected option life. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for the estimated life of the option. The following assumptions were used to estimate the fair value of options granted using the Black-Scholes option-pricing model:



	For the nine months ended
	September 30,
	2020	2019

Risk free interest rate	1.66%	1.37% - 2.47%
Dividend yield	1.3%	1.3%
Expected volatility	20%	20%
Expected lives	4.6 years	4.6 years

The following table summarizes the Company’s activities with respect to its stock option plans for the nine months ended September 30, 2020 as follows (dollars and shares in thousands, except for per share data):



		Weighted-		Weighted-Average
		Average		Remaining
	Number	Exercise Price		Contractual	Aggregate
	of Shares	Per Share		Life (in years)	Intrinsic Value
Outstanding at December 31, 2019	4,507	$	133.68
Granted	10	$	240.99
Exercised	(1,266)	$	110.44
Forfeited/canceled	(28)	$	168.11
Outstanding at September 30, 2020	3,223	$	142.84	4.0	$	566,269
Exercisable at September 30, 2020	1,722	$	124.84	3.3	$	333,471
Unvested at September 30, 2020	1,501	$	163.47	4.8	$	232,798

The weighted-average per share fair value of options granted during the nine months ended September 30, 2020 was $41.09. The total intrinsic value for options exercised during the nine months ended September 30, 2020 was $231.1 million.

The following table summarizes the Company’s RSU and PSU activity for the nine months ended September 30, 2020:



	RSUs			PSUs
		Weighted-Average			Weighted-Average
	Number of	Grant Date Fair		Number of	Grant Date Fair
	Shares	Value per Share		Shares	Value per Share
	(in thousands)			(in thousands)
Outstanding at December 31, 2019	313	$	152.98	—	$	—
Granted ⁽¹⁾	99	$	290.77	149	$	376.48
Vested	(129)	$	142.06	—	$	—
Forfeited/canceled	(8)	$	200.03	(1)	$	376.50
Outstanding at September 30, 2020	275	$	206.51	148	$	376.48