We issue equity-based awards to our employees pursuant to the 2017 Omnibus Incentive Plan (“2017 Employee Plan”) and our non-employee directors pursuant to the 2017 Stock Plan for Non-Employee Directors (“2017 Director Plan”). The 2017 Employee Plan provides that a maximum of 8,000,000 shares of our common stock may be issued, and as of December 31, 2019, 5,495,914 shares of common stock remain available for future issuance. The 2017 Director Plan provides that a maximum of 450,000 shares of our common stock may be issued, and as of December 31, 2019, 293,269 shares of common stock remain available for future issuance. For each of the years ended December 31, 2019 and 2018, we recognized $16 million, respectively, of share-based compensation expense and $15 million for the year ended December 31, 2017. As of December 31, 2019, unrecognized compensation expense was $16 million, which is expected to be recognized over a weighted-average period of 1.2 years. The total fair value of shares vested during the year ended December 31, 2019 was $21 million and $9 million for each of the years ended December 31, 2018 and 2017.

Restricted Stock Awards (“RSAs”) generally vest in annual installments between one and three years from each grant date. The following table provides a summary of RSAs for the years ended December 31, 2019, 2018 and 2017:

	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at January 1, 2017		—		$	—
Granted		594,213			26.52
Vested		(106,795	)		26.85
Forfeited		(25,779	)		26.22
Unvested at December 31, 2017		461,639			26.47
Granted		367,463			27.34
Vested		(214,208	)		26.67
Forfeited		(29,788	)		27.48
Unvested at December 31, 2018		585,106			26.89
Granted		302,506			31.24
Vested		(312,462	)		26.99
Forfeited		(17,905	)		29.58
Unvested at December 31, 2019		557,245		$	29.10

Performance Stock Units (“PSUs”) generally vest at the end of a three-year performance period and are subject to the achievement of a market condition based on a measure of our total shareholder return relative to the total shareholder return of the companies that comprise the FTSE Nareit Lodging Resorts Index (that have a market capitalization in excess of $1 billion as of the first day of the applicable performance period). The number of PSUs that may become vested ranges from zero to 200% of the number of PSUs granted to an employee, based on the level of achievement of the foregoing performance measure. The following table provides a summary of PSUs for the years ended December 31, 2019, 2018 and 2017:

	Number of Shares			Weighted-Average Grant Date Fair Value
Unvested at January 1, 2017		—		$	—
Granted		387,642			31.95
Vested		—			—
Forfeited		(16,085	)		31.73
Unvested at December 31, 2017		371,557			31.96
Granted		179,774			29.47
Vested		—			—
Forfeited		(13,395	)		30.48
Unvested at December 31, 2018		537,936			31.16
Granted		314,858			34.28
Vested		(277,325	)		31.25
Forfeited		(672	)		42.05
Unvested at December 31, 2019		574,797		$	32.82

The grant date fair values of these awards were determined using a Monte Carlo simulation valuation model with the following assumptions:

	Year Ended December 31,
	2019		2018		2017
Expected volatility⁽¹⁾	19.5% - 21.5%		20.0% - 24.0%		25.5% - 29.5%
Dividend yield⁽²⁾		—		—		—
Risk-free rate	1.8% - 2.4%		2.4% - 2.7%		1.2% - 1.5%
Expected term	3 years		3 years		2 - 3 years