In exchange for services provide by certain employees, the Company grants equity-based compensation under the Equity Incentive Plan. Based on a formula as defined in the Equity Incentive Plan, the total number of shares available to be issued under the Equity Incentive Plan resets and may increase on January 1 each year. Accordingly, on January 1, 2019, the total number of shares available for issuance under the Equity Incentive Plan reset to 32,792,005 shares, and as of December 31, 2019, 28,930,797 shares remain available for issuance.

Generally, unvested phantom shares, restricted units and options are forfeited upon termination of employment in accordance with the Equity Incentive Plan. The Company recognizes forfeitures as a reversal of previously recognized compensation expense in the period the forfeiture occurs.


	For the Year Ended December 31,
	2019		2018		2017
Restricted units	$	88,979	$	74,441	$	54,339
Restricted units with a market condition	3,613		1,524		—
Options	4,362		12,449		13,848
Phantom shares	737		1,310		1,524
Equity-based compensation expense	$	97,691	$	89,724	$	69,711

During July 2018, the Company granted 2,000,000 restricted units to an executive of which 1,333,334 restricted units are subject to vesting based on the future price of shares of the Company's Class A common stock (described in greater detail below under the heading “Restricted Unit Awards with a Market Condition”) and 666,666 restricted units that vest subject to the executive's continued service on terms similar to those described below.

Each restricted unit represents an unfunded, unsecured right of the holder to receive a share of the Company's Class A common stock on a specific date. The restricted units generally vest and are settled in shares of Class A common stock either (i) at a rate of one-third per year, beginning on the third anniversary of the grant date, (ii) in their entirety on the fifth anniversary of the grant date, (iii) at a rate of one quarter per year, beginning on either the first or second anniversary of the grant date or the holder's employment commencement date, or (iv) at a rate of one third per year, beginning on the first anniversary of the grant date in each case generally subject to the holder’s continued employment as of the applicable vesting date (subject to accelerated vesting upon certain qualifying terminations of employment). Compensation expense associated with restricted units is recognized on a straight-line basis over the requisite service period of the award.

The holders of restricted units, other than the market condition awards described below, generally have the right to receive as current compensation an amount in cash equal to (i) the amount of any dividend paid with respect to a share of Class A common stock multiplied by (ii) the number of restricted units held at the time such dividends are declared (“Dividend Equivalent”). During the year ended December 31, 2019, the Company declared a dividend each quarter of $0.32 per share to Class A common stockholders at the close of business on March 15, 2019, June 14, 2019, September 16, 2019, and December 17, 2019, respectively. For the year ended December 31, 2019, Dividend Equivalents were made to the holders of restricted units in the aggregate amount of $21.5 million, which are presented as a component of dividends within the Consolidated Statements of Changes in Equity. When units are forfeited, the cumulative amount of dividend equivalents previously paid is reclassified to compensation and benefits expense in the Consolidated Statements of Operations.


	Restricted Units	Weighted Average Grant Date Fair Value Per Unit
Balance - January 1, 2019	16,255,475	$	19.21
Granted	4,499,563	21.42
Vested	(3,691,234)	17.96
Forfeited	(253,331)	19.68
Balance - December 31, 2019	16,810,473	$	20.07

The total compensation expense expected to be recognized in all future periods associated with the restricted units is approximately $203.0 million as of December 31, 2019 and is expected to be recognized over the remaining weighted average period of 2.81 years.

In July 2018, the Company granted certain restricted units with a vesting condition based upon the volume-weighted, average closing price of shares of the Company’s Class A common stock meeting or exceeding a stated price for 30 consecutive calendar days on or prior to January 1, 2028, referred to as a market condition. 666,667 restricted units with a market condition of $35.00 per share (“Tranche I”) and 666,667 restricted units with a market condition of $45.00 per share (“Tranche II”) were granted. Vesting is also generally subject to continued employment at the time such market condition is achieved. Under the terms of the awards, if the price target is not achieved by the close of business on January 1, 2028, the unvested market condition awards will be automatically canceled and forfeited. Restricted units subject to a market condition are not eligible to receive a Dividend Equivalent.

a probability distributed Monte-Carlo simulation. Due to the existence of the market condition, the vesting period for the awards is not explicit, and as such, compensation expense is recognized on a straight-line basis over the median vesting period

Below is a summary of the significant assumptions used to estimate the grant date fair value of the market condition awards. There were no new market condition awards granted during the year ended December 31, 2019.


	Market Condition Awards Units	Weighted Average Grant Date Fair Value Per Unit
Balance - January 1, 2019	1,333,334	$	9.30
Granted	—	—
Vested	—	—
Forfeited	—	—
Balance - December 31, 2019	1,333,334	$	9.30

The total compensation expense expected to be recognized in all future periods associated with the market condition awards is approximately $7.3 million as of December 31, 2019 and is expected to be recognized over the remaining weighted average period of 2.2 years.

Each option entitles the holders to purchase from the Company, upon exercise thereof, one share of Class A common stock at the stated exercise price. The term of the options is generally ten years, beginning on the grant date. The options generally vest at a rate of one-third per year, beginning on the third anniversary of the grant date. Compensation expense associated with these options is being recognized on a straight-line basis over the requisite service period of the respective award. Net cash proceeds from exercises of stock options were $90.5 million for the year ended December 31, 2019. The Company realized tax benefits of approximately $4.3 million from those exercises.


	Options	Weighted Average Exercise Price		Weighted Average Remaining Life (in years)	Aggregate Intrinsic Value
Balance - January 1, 2019	18,741,504	$	18.99	4.88	$	—
Granted	—	—		—	—
Exercised	(4,905,998)	19.00		—	—
Expired	(366,366)	19.00		—	—
Forfeited	(42,270)	19.00		—	—
Balance - December 31, 2019	13,426,870	$	18.99	4.34	$	224,260
Exercisable at December 31, 2019	13,317,053	$	18.99	4.33	$	222,372

Aggregate intrinsic value represents the value of the Company’s closing share price of Class A common stock on the last trading day of the period in excess of the weighted-average exercise price multiplied by the number of options exercisable or expected to vest.

The fair value of an award is affected by the Company’s share price of Class A common stock on the date of grant as well as other assumptions including the estimated volatility of the Company’s share price of Class A common stock over the term of the awards and the estimated period of time that management expects employees to hold their unit options. The estimated period of time that management expects employees to hold their options was estimated as the midpoint between the vesting date and maturity date.

Each phantom share represents an unfunded, unsecured right of the holder to receive an amount in cash per phantom share equal to the average closing price of a share of Class A common stock for the 15 trading days immediately prior to, and the 15 trading days immediately following, the vesting date. The phantom shares vested in equal installments over five years at the anniversaries of the IPO date, with the final payment made in May 2019. The phantom shares are accounted for as liability awards with compensation expense being recognized on a straight-line basis based on the number of unvested shares. Forfeitures will reduce the expenses in the period in which the forfeiture occurs. During the year ended December 31, 2019 the Company paid $1.5 million to settle vested phantom shares.