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

The Company implemented an Employee Stock Purchase Plan (ESPP) which became effective on December 8, 2020. Under the ESPP, eligible employees are granted options to purchase common stock at the lower of 85% of the fair market value of the stock at the time of grant or 85% of the fair market value at the time of exercise. Options to purchase shares are granted twice yearly on or about January 1 and July 1, and exercisable on or about the succeeding July 1, and January 1, respectively, of each year. No participant may purchase more than $25,000 worth of shares in a six-month offering period, or a maximum of 2,400 shares. There are 5,000,000 shares available for issuance under the ESPP. The stock-based compensation cost of the ESPP options are measured based on grant date at fair value and are recognized on a straight-line basis over the offering period. The ESPP did not have a material impact on stock-based compensation expense during the year ended December 31, 2022.

Aggregate stock-based compensation charges were $27.1 million, $23.9 million and $17.9 million during the years ended December 31, 2022, 2021 and 2020, respectively. Routine stock-based compensation expense is included as a component of “Selling, general and administrative” expense on the accompanying Consolidated Statements of Operations. As of December 31, 2022, there was $22.3 million of unrecognized stock‑based

During December 2010, the Company and the common stockholders approved the Americold Realty Trust 2010 Equity Incentive Plan (2010 Plan), whereby the Company could issue stock options, stock appreciation rights, restricted stock, restricted stock units, stock bonus awards, and/or dividend equivalents with respect to the Company’s common stock, cash bonus awards, and/or performance compensation awards to certain eligible participants, as defined, based upon a reserved pool of 3,849,976 of the Company’s common shares. No additional awards may be granted under the 2010 Plan.

On January 4, 2018, the Company’s Board of Directors 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 shares of common stock of the Company. On January 17, 2018, the Company’s stockholders 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 for market performance-based awards are forfeitable in the event of termination for cause or when voluntary departure occurs during the vesting period and otherwise, paid upon the vesting of the awards. Time-based awards have the right to receive nonforfeitable dividend equivalent distributions on unvested units throughout the vesting period.

All awards granted under the 2017 Plan dated on March 8, 2020 and thereafter include a retirement provision. The retirement provision allows that if a participant has either attained the age of 65, or has attained the age of 55 and has ten full years of service with the Company, and there are no facts, circumstances or events exist which would give the Company a basis to effect a termination of service for cause, then the award recipient is entitled to continued vesting of any outstanding equity-based awards which include the retirement provision. Should the participant choose to retire from the Company, the awards with the retirement provision would continue to vest. Accordingly, grants of time-based awards to an associate who has met the retirement criteria on or before the date of grant will be expensed at the date of grant. In addition, grants of time-based awards to associates who will meet the retirement criteria during the awards normal vesting period will be expensed between the date of grant and the date upon which the award recipient meets the retirement criteria. Time-based awards granted to recipients who meet the retirement criteria, and decide to retire, will continue vesting on the original vesting schedule as determined at grant date. A pro-rated portion of market-performance based awards granted to recipients who meet the retirement criteria will remain outstanding and eligible to vest based on actual performance through the last day of the performance period based on the number of days during the performance period that the recipient was employed.

Restricted stock units are nontransferable until vested. Prior to the issuance of a share of common stock, 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. The grant date fair values for time-based restricted unit stock awards is equal to the closing market price of Americold Realty Trust, Inc. common stock on the grant date. Market performance-based restricted stock unit awards cliff vest upon the achievement of the performance target, as well as completion of performance period.


Year Ended December 31	Grantee Type	Number of Restricted Stock Units Granted	Vesting Period	Grant Date Fair Value (in thousands)
2022	Directors	4,810	1 year	$	125
2022	Associates	555,719	1-3 years	$	15,067
2021	Directors	6,616	1 year	$	250
2021	Associates	1,004,650	1-3 years	$	31,159
2020	Directors	8,517	1 year	$	300
2020	Associates	295,274	1-3 years	$	9,137

Restricted stock units granted for the year ended December 31, 2022 consisted of: (i) 4,810 time-based restricted stock units with a one-year vesting period issued to non-employee directors as part of their annual compensation (ii) 424,543 time-based graded vesting restricted stock units with various vesting periods ranging from one to three years issued to certain associates in connection with the annual grant provided in March (iii) 131,176 market performance-based cliff vesting restricted stock units with a three-year vesting period issued to certain associates.

Restricted stock units granted for the year ended December 31, 2021 consisted of: (i) 6,616 time-based restricted stock units with a one-year vesting period issued to non-employee directors as part of their annual compensation (ii) 216,269 time-based graded vesting restricted stock units with various vesting periods ranging from one to three years issued to certain associates in connection with the annual grant provided in March (iii) 108,781 market performance-based cliff vesting restricted stock units with a three-year vesting period issued to certain associates n connection with the annual grant provided in March and (iv) 679,600 time-based graded vesting restricted stock units with various vesting periods ranging from one to two years issued to certain associates as a retention grant in November of 2021.

Restricted stock units granted for the year ended December 31, 2020 consisted of: (i) 8,517 time-based restricted stock units with a one-year vesting period issued to non-employee directors as part of their annual compensation, (ii) 186,464 time-based graded vesting restricted stock units with various vesting periods ranging from one to three years years issued to certain associates and (iv) 108,810 market performance-based cliff vesting restricted stock units with a three-year vesting period issued to certain associates.


Year Ended December 31, 2022
Restricted Stock	Number of Time-Based Restricted Stock Units	Aggregate Intrinsic Value (in millions)		Number of Market Performance-Based Restricted Stock Units(2)	Aggregate Intrinsic Value (in millions)
Non-vested as of December 31, 2021	1,071,959	$	35.1	374,048	$	12.3
Granted	429,353			131,176
Market-performance adjustment(3)	N/A			(18,253)
Vested	(623,882)			(194,111)
Forfeited	(189,763)			(43,413)
Non-vested as of December 31, 2022	687,667	$	19.5	249,447	$	7.1
Shares vested, but not released(1)	46,890	1.3		—	—
Total outstanding restricted stock units	734,557	$	20.8	249,447	$	7.1

(1)For certain vested restricted stock units, common stock issuance is contingent upon the first to occur of: (1) termination of service; (2) change in control; (3) death; or (4) disability, as defined in the 2010 Plan. Of these vested time-based restricted stock units 46,890 belong to an active member of the Board of Directors and the date of issuance is therefore unknown at this time. The weighted average grant date fair value of these units is $8.42 per unit. Holders of these certain vested restricted stock units are entitled to receive dividends, but are not entitled to vote until such stock is issued.

The weighted average grant date fair value of restricted stock units granted during years 2022, 2021, and 2020 was $27.10, $31.06 and $31.06 per unit, respectively. During the year ended December 31, 2022 the weighted average grant date fair value of vested and converted restricted stock units was $31.47 and forfeited restricted stock units was $29.51. The weighted average grant date fair value of non-vested restricted stock units was $28.15 and $31.40 per unit as of December 31, 2022 and 2021, respectively.

During each of the years ended December 31, 2022, 2020 and 2019, the Compensation Committee of the Board of Directors approved the annual grant of market performance-based restricted stock units under the 2017 Plan to associates of the Company. The awards utilize relative total stockholder return (TSR) over a three-year measurement period as the market performance metric. Awards will vest based on the Company’s TSR relative to the MSCI US REIT Index (RMZ) over a three-year market performance period, or the Market Performance Period, commencing on January 1st of the grant year and ending on December 31st of the third year, as applicable (or, if earlier, ending on the date on which a change in control of the Company occurs), subject to continued services. Vesting with respect to the market condition is measured based on the difference between the Company’s TSR percentage and the TSR percentage of the RMZ, or the RMZ Relative Market Performance. In the event that the RMZ Relative Market Performance during the Market Performance Period is achieved at the “threshold,” “target” or “high” level as set forth below, the awards will become vested as to the market condition with respect to the percentage of RSUs, as applicable, set forth below:

The fair values of the awards were measured using a Monte Carlo simulation to estimate the probability of the market vesting condition being satisfied. The Company’s achievement of the market vesting condition is contingent on its TSR over a three-year market performance period, relative to the total stock price. Monte Carlo simulation is well-accepted for pricing market based awards, where the number of shares that will vest depends on the future stock price movements. For each simulated path, the TSR is calculated at the end of the performance period and determines the vesting percentage based on achievement of the performance target. The fair value of the RSUs is the average discounted payout across all simulation paths. Assumptions used in the valuations are summarized as follows:

OP units granted for the year ended December 31, 2022 consisted of: (i) 35,593 time-based OP units with a one year vesting period issued to non-employee directors as part of their annual compensation, (ii) 98,994 time-based graded vesting OP units with various vesting periods ranging from one to three years issued to certain associates in connection with the annual grant provided in March and (iii) 243,986 market performance-based cliff vesting OP units with a three-year vesting period issued to certain associates in connection with the annual grant provided in March.

OP units granted for the year ended December 31, 2021 consisted of: (i) 22,427 time-based OP units with a one-year vesting period issued to non-employee directors as part of their annual compensation (ii) 102,655 time-based graded vesting OP units with various vesting periods ranging from one to three years issued to certain associates in connection with the annual grant provided in March (iii) 198,007 market performance-based cliff vesting OP units with a three-year vesting period issued to certain associates in connection with the annual grant provided in March and (iv) 8,200 time-based graded vesting OP units with a two-year vesting period issued to certain associates as a retention grant in November of 2021.

OP units granted for the year ended December 31, 2020 consisted of: (i) 16,325 time-based OP units with a one-year vesting period issued to non-employee directors as part of their annual compensation (ii) 76,855 time-based graded vesting OP units with various vesting periods ranging from one to three years issued to certain associates and (iii) 178,865 market performance-based cliff vesting OP units with a three-year vesting period issued to certain associates.


Year Ended December 31, 2022
OP Units	Number of Time-Based OP Units	Aggregate Intrinsic Value (in millions)		Number of Market Performance-Based OP Units	Aggregate Intrinsic Value (in millions)
Non-vested as of December 31, 2021	140,222	$	4.6	288,165	$	9.4
Granted	134,587			243,986
Vested	(102,234)			—
Forfeited	(12,393)			(69,336)
Non-vested as of December 31, 2022	160,182	$	4.5	462,815	$	13.1
Shares vested, but not released	174,958	5.8		—	—
Total outstanding OP units	335,140	$	10.3	462,815	$	13.1

The OP units granted for the years ended December 31, 2022, 2021 and 2020 had an aggregate grant date fair value of $10.0 million, $10.7 million and $8.3 million, respectively. During the year ended December 31, 2022 the weighted average grant date fair value of vested OP units was $30.90 and forfeited OP units was $29.30. The weighted average grant date fair value of non-vested OP units was $29.39 and $31.30 per unit as of December 31, 2022 and 2021, respectively.


	Number of Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Terms (Years)
Outstanding as of December 31, 2021	206,298	$	9.81	2.9
Granted	—	—
Exercised	(100,800)	9.81
Forfeited or expired	—	—
Outstanding as of December 31, 2022	105,498	$	9.81	3.6

Exercisable as of December 31, 2022	105,498	$	9.81	3.6