Share-Based Compensation

All share-based compensation cost is measured at the grant date, based on the estimated fair value of the award. The Company issues both time-based, performance-based and market-based equity awards. Time-based awards are recognized on a straight-line basis over the employees’ requisite service period, as adjusted for estimate of forfeitures. Performance-based and market-based awards are recognized on a tranche-by-tranche basis over the performance period, as adjusted for estimate of forfeitures.

Aggregate stock-based compensation charges were $4.5 million and $0.6 million during the three months ended March 31, 2018 and 2017, respectively, and were included as a component of "selling, general and administrative" expense on the accompanying condensed consolidated statements of operations. As of March 31, 2018, there was $19.7 million of unrecognized stock‑based compensation expense related to stock options and restricted stock units, which will be recognized over a weighted-average period of 2.9 years.

Americold Realty Trust 2017 Equity Incentive Plan

On January 4, 2018, the Company's board of trustees adopted the Americold Realty Trust 2017 Equity Incentive Plan (2017 Plan), which permits the grant of various forms of equity- and cash-based awards from a reserved pool of 9,000,000 common shares of the Company. On January 17, 2018, the Company's then shareholders approved the 2017 Plan. Equity-based awards issued under the 2017 Plan have the rights to receive dividend equivalents on an accrual basis. Dividend equivalents accrued are paid upon the vesting of the awards, and for awards that are forfeited during the vesting period no dividend equivalents will be paid. Certain restricted stock units issued in connection with the IPO to retain key employees of the Company have the right to receive nonforfeitable dividend equivalent distributions on unvested units.

Modification of Restricted Stock Units

On January 4, 2018, the Company’s board of trustees approved the modification of awards to allow the grant of dividend equivalents to all participants in the 2010 Plan with respect to any and all vested restricted stock units of the Company that have not been settled pursuant to the 2010 Plan. On the same day, the Company’s board of trustees resolved that no further awards may be granted under the 2010 Plan after the approval of the 2017 Plan. As a result, the Company recognized a stock-based compensation expense of $2.6 million to reflect the change in fair value associated with the modification of the dividend equivalents rights of the outstanding equity awards under the 2010 Plan.

Restricted Stock Units Activity

Restricted stock units are nontransferable until vested. Prior to the issuance of a common share, the grantees of restricted stock units are not entitled to vote the shares. Time-based restricted stock unit awards vest in equal annual increments over the vesting period. Performance-based and market-based restricted stock unit awards vest upon the achievement of the performance target.

The following table summarizes restricted stock unit grants under the 2017 Plan during the three months ended March 31, 2018 and under the 2010 Plan for the three months ended March 31, 2017:



March 31,	Grantee Type	# of Restricted Stock Units Granted	Vesting Period	Grant Date Fair Value (in thousands)
2018	Trustee group	373,438	1-3 years	$	5,975
2018	Employee group	897,125	2-4 years	$	12,677
2017	Trustee group	18,348	2-3 years	$	199
2017	Employee group	71,428	5 years	$	959

Of the restricted stock units granted during the first quarter of 2018, i) 729,375 were time-based restricted stock units with various vesting periods ranging from one to four years issued to non-employee trustees and certain employees, ii) 42,188 were time-based restricted stock units with a one year vesting period issued to non-employee trustees as part of their annual compensation, and iii) 499,000 were market-based restricted stock units issued to certain employees. The vesting of such market-based awards will be determined based on the Company's "total shareholder return", as described in the agreement granting such awards, computed for the performance period that began January 18, 2018 and will end December 31, 2020.

As of March 31, 2018, the Company's vested and outstanding restricted stock units had an intrinsic value of approximately $31.4 million using a price per share of $19.08.

Stock Options Activity

The following tables provide a summary of option activity for the three months ended March 31, 2018 and 2017:



Options	Shares (In thousands)		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Terms (Years)
Outstanding as of December 31, 2017	5,478		$	9.72	6.0
Granted	—		—
Exercised	(95	)	7.85
Forfeited or expired	(70	)	9.81
Outstanding as of March 31, 2018	5,313		9.76		5.8

Exercisable as of March 31, 2018	3,666		$	9.73	4.9



Outstanding as of December 31, 2016	6,313		$	9.72	6.8
Granted	—		—
Exercised	—		—
Forfeited or expired	(286	)	9.81
Outstanding as of March 31, 2017	6,027		9.71		6.3

Exercisable as of March 31, 2017	3,537		$	9.64	4.7

As of March 31, 2018, the Company's exercisable and outstanding stock options had an intrinsic value of approximately $43.5 million using a price per share of $19.08.