We currently issue equity awards under the CoreLogic, Inc. 2018 Performance Incentive Plan (the "Plan"), which was approved by our stockholders at our Annual Meeting held in May 2018. The Plan includes the ability to grant share-based instruments such as restricted stock units ("RSUs"), performance-based restricted stock units ("PBRSUs") and stock options. Prior to the approval of the Plan, we issued share-based awards under the CoreLogic, Inc. 2011 Performance Incentive Plan, as amended, which was preceded by the CoreLogic, Inc. 2006 Incentive Plan. The Plan provides for up to 15,139,084 shares of the Company's common stock to be available for award grants.

We have primarily utilized RSUs and PBRSUs as our share-based compensation instruments for employees and directors. The fair value of any share-based compensation instrument grant is based on the market value of our common stock on the date of grant and is recognized as compensation expense over its vesting period.

For the six months ended June 30, 2019 and 2018, we awarded 628,730 and 529,725 RSUs, respectively, with an estimated grant-date fair value of $23.0 million and $24.8 million, respectively. The RSU awards will vest ratably over 3 years. RSU activity for the six months ended June 30, 2019 is as follows:



	Number of Shares		Weighted-Average Grant-Date Fair Value
(in thousands, except weighted-average fair value prices)	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested RSUs outstanding at December 31, 2018	1,087		$	42.04
RSUs granted	629		$	36.50
RSUs vested	(513	)	$	40.36
RSUs forfeited	(61	)	$	40.15
Unvested RSUs outstanding at June 30, 2019	1,142		$	39.85

As of June 30, 2019, there was $32.5 million of total unrecognized compensation cost related to unvested RSUs that is expected to be recognized over a weighted-average period of 2.1 years. The fair value of RSUs are based on the market value of our common stock on the date of grant.

For the six months ended June 30, 2019 and 2018, we awarded 203,464 and 327,018 PBRSUs, respectively, with an estimated grant-date fair value of $7.5 million and $15.1 million, respectively. These awards are generally subject to service-based, performance-based and market-based vesting conditions. The service and performance period for the 2019 grants is from January 2019 to December 2021 and the performance metric is adjusted earnings per share.

The performance and service period for the PBRSUs awarded during 2018 is from January 2018 to December 2020 and the performance metrics are generally adjusted earnings per share and market-based conditions. These grants include 232,225 PBRSUs that do not include a market-based condition but have adjusted margin or operating revenue as the performance metric through the service period ending December 2020 or December 2021.

The fair values of the awards containing market-based vesting conditions were estimated using Monte-Carlo simulation with the following weighted-average assumptions:



	For the Six Months Ended June 30,
	2019		2018
Expected dividend yield	—	%	—	%
Risk-free interest rate ⁽¹⁾	2.44	%	2.38	%
Expected volatility ⁽²⁾	28.24	%	23.63	%
Average total stockholder return ⁽²⁾	17.15	%	6.11	%

(1) The risk-free interest rate for the periods within the contractual term of the PBRSUs is based on the U.S. Treasury yield curve in effect at the time of the grant. (2) The expected volatility and average total stockholder return are measures of the amount by which a stock price has fluctuated or is expected to fluctuate based primarily on our and our peers' historical data.



	Number of Shares		Weighted-Average Grant-Date Fair Value
(in thousands, except weighted-average fair value prices)	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested PBRSUs outstanding at December 31, 2018	774		$	42.11
PBRSUs granted	203		$	36.82
PBRSUs vested	(250	)	$	34.40
PBRSUs forfeited	(100	)	$	45.07
Unvested PBRSUs outstanding at June 30, 2019	627		$	42.68

As of June 30, 2019, there was $18.5 million of total unrecognized compensation cost related to unvested PBRSUs that is expected to be recognized over a weighted-average period of 2.0 years. The fair value of PBRSUs are based on the market value of our common stock on the date of grant.

Prior to 2015, we issued stock options as incentive compensation for certain employees. Option activity for the six months ended June 30, 2019 is as follows:



(in thousands, except weighted-average price)	Number of Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value
Options outstanding at December 31, 2018	570		$	20.17
Options exercised	(70	)	$	25.24
Options vested, exercisable, and outstanding at June 30, 2019	500		$	19.46	2.8	$	11,175

The intrinsic value of options exercised was $1.1 million and $13.6 million for the six months ended June 30, 2019 and 2018, respectively. This intrinsic value represents the difference between the fair market value of our common stock on the date of exercise and the exercise price of each option.

The employee stock purchase plan allows eligible employees to purchase our common stock at 85.0% of the lesser of the closing price on the first day or the last day of each quarter. Our employee stock purchase plan was approved by our stockholders at our 2012 annual meeting of stockholders and the first offering period commenced in October 2012. We recognized an expense for the amount equal to the estimated fair value of the discount during each offering period.

The following table sets forth the share-based compensation expense recognized for the three and six months ended June 30, 2019 and 2018:



	For the Three Months Ended				For the Six Months Ended
	June 30,				June 30,
(in thousands)	2019		2018		2019		2018
RSUs	$	5,612	$	7,238	$	12,924	$	14,633
PBRSUs	1,744		3,445		3,658		4,159
Stock options	—		—		—		—
Employee stock purchase plan	507		439		1,173		1,007
	$	7,863	$	11,122	$	17,755	$	19,799