The following table summarizes restricted stock awards activity for the nine months ended September 30, 2019:

	Time-Based					Market-Based
	Restricted Stock Awards					Restricted Stock Awards
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
Unvested shares of restricted stock outstanding at December 31, 2018		806.5		$	67.54		—		$	—
Granted		338.9			151.10		281.0			102.76
Vested		(318.5	)		64.06		(280.4	)		102.76
Forfeited		(77.8	)		85.82		(0.6	)		102.57
Unvested shares of restricted stock outstanding at September 30, 2019		749.1		$	104.92		—		$	—

In January 2019, we issued an aggregate of 520,069 restricted shares of common stock to our executive officers, certain non-executive, non-sales employees and non-executive sales management employees under the Paycom Software, Inc. 2014 Long-Term Incentive Plan (the “LTIP”), consisting of 280,960 shares subject to market-based vesting conditions (“Market-Based Shares”) and 239,109 shares subject to time-based vesting conditions (“Time-Based Shares”). Market-Based Shares vested 50% on the first date that the Company’s total enterprise value (“TEV”) (calculated as defined in the applicable restricted stock award agreement) equaled or exceeded $8.65 billion and 50% on the first date that the Company’s TEV equaled or exceeded $9.35 billion, in each case provided that (i) such date occurred on or before the sixth anniversary of the grant date and (ii) the recipient was employed by, or providing services to, the Company on the applicable vesting date. As shown in the table below, all Market-Based Shares issued in January 2019 have vested.

On April 23, 2019, we issued an aggregate of 65,255 restricted shares of common stock to certain non-executive employees under the LTIP consisting of Time-Based Shares that will vest in either three or four equal tranches annually, generally beginning on the first anniversary of the grant date, provided that the recipient is employed by, or providing services to, the Company on the applicable vesting date.

On April 29, 2019, we issued an aggregate of 6,816 restricted shares of common stock under the LTIP to the non-employee members of our Board of Directors. Such shares of restricted stock will cliff-vest on the seventh day following the first anniversary of the date of grant, provided that such director is providing services to the Company through the applicable vesting date.

In May 2019, we issued an aggregate of 26,000 restricted shares of common stock to certain non-executive employees under the LTIP consisting of Time-Based Shares that will vest over periods ranging from two to four years, provided that the recipient is employed by, or providing services to, the Company on the applicable vesting date.

The following table summarizes vesting activity for Market-Based Shares during the nine months ended September 30, 2019, the associated compensation cost recognized in connection with each vesting event and the number of shares withheld to satisfy tax withholding obligations:

Vesting Condition

Date Vested

Number of Shares

Vested

Compensation

Cost Recognized

Upon Vesting

Shares Withheld

for Taxes¹

Market-based (TEV = $8.65 billion)

February 13, 2019

140.2

$14,900

54.5

Market-based (TEV = $9.35 billion)

February 22, 2019

140.2

$13,900

55.5

Time-Based Shares granted to certain non-executive employees in January 2019 will vest 25% on a specified initial vesting date and 25% on each of the first three anniversaries of such initial vesting date, provided that the recipient is employed by, or providing services to, the Company or a subsidiary on the applicable vesting date. Time-Based Shares granted to executive officers, sales management employees and certain non-executive employees will generally vest over periods ranging from two to four years beginning on a specified initial vesting date and thereafter on the anniversaries of such date, provided that the executive officer or employee is employed by, or providing services to, the Company on the applicable vesting date.

For the three and nine months ended September 30, 2019, our total compensation expense related to restricted stock was $4.5 million and $41.1 million, respectively. For the three and nine months ended September 30, 2018, our total compensation expense related to restricted stock was $4.5 million and $31.5 million, respectively. There was $62.6 million of unrecognized compensation cost, net of estimated forfeitures, related to unvested shares of restricted stock outstanding as of September 30, 2019. The unrecognized compensation cost for the unvested shares is expected to be recognized over a weighted average period of 2.4 years as of September 30, 2019.

We capitalized stock-based compensation costs related to software developed for internal use of $0.3 million and $4.3 million for the three and nine months ended September 30, 2019, respectively. We capitalized stock-based compensation costs related to software developed for internal use of $0.4 million and $3.3 million for the three and nine months ended September 30, 2018, respectively.