STOCK-BASED EMPLOYEE COMPENSATION

Stock-based compensation expense included in personnel expenses in the Unaudited Consolidated Statements of Operations was approximately $35.2 million and $34.7 million for the three months ended June 30, 2014 and 2013, respectively, and $74.0 million and $56.4 million for the six months ended June 30, 2014 and 2013, respectively.

The cost of stock-based transactions is recognized in the financial statements based upon fair value. Fair value is recognized as expense on a straight line basis, net of estimated forfeitures, over the employee requisite service period. The fair value of performance share units and restricted stock units is determined based on the number of units granted and the quoted price of the Company's common stock as of the grant date. Stock-based compensation related to performance share units reflects the estimated probable outcome at the end of the performance period. The fair value of employee stock options assumed in acquisitions was determined using the Black-Scholes model and the market value of the Company's common stock at the respective acquisition date.

Restricted Stock Units and Performance Share Units

The following table summarizes the activity of restricted stock units and performance share units ("share-based awards") during the six months ended June 30, 2014:



Share-Based Awards	Shares		Weighted Average Grant Date Fair Value
Unvested at December 31, 2013	534,319			$	615.10
Granted	101,003			$	1,328.71
Vested	(181,920	)		$	470.62
Performance Share Units Adjustment	27,384			$	795.67
Forfeited	(4,966	)		$	843.61
Unvested at June 30, 2014	475,820			$	829.82

As of June 30, 2014, there was $234.9 million of total future compensation cost related to unvested share-based awards to be recognized over a weighted-average period of 2.1 years.

During the six months ended June 30, 2014, the Company made broad-based grants of 35,788 restricted stock units that generally vest after three years. These share-based awards had a total grant date fair value of $47.2 million based on a weighted average grant date fair value per share of $1,319.74.

In addition, during the six months ended June 30, 2014, the Company granted 65,215 performance share units to executives and certain other employees. The performance share units had a total grant date fair value of $87.0 million based upon a weighted average grant date fair value per share of $1,333.63. The performance share units are payable in shares of the Company's common stock upon vesting. Subject to certain exceptions for terminations other than for "cause," for "good reason" or on account of death or disability, recipients of these performance share units must continue their service through the three year requisite service period in order to receive any shares. Stock-based compensation related to performance share units reflects the estimated probable outcome at the end of the performance period. The actual number of shares to be issued on the vesting date will be determined upon completion of the performance period, which, for most of these performance share units, ends December 31, 2016, assuming there is no accelerated vesting for, among other things, a termination of employment under certain circumstances. As of June 30, 2014, the estimated number of probable shares to be issued is a total of 65,215 shares. If the maximum performance thresholds are met at the end of the performance period, a maximum number of 130,430 total shares could be issued. If the minimum performance thresholds are not met, 45,786 shares would be issued at the end of the performance period.

2013 Performance Share Units

During the year ended December 31, 2013, the Company granted 104,865 performance share units with a grant date fair value of $74.4 million, based on a weighted average grant date fair value per share of $709.74. The actual number of shares to be issued will be determined upon completion of the performance period which ends December 31, 2015.

At June 30, 2014, there were 103,104 unvested 2013 performance share units outstanding, net of performance share units that were forfeited or vested since the grant date. As of June 30, 2014, the number of shares estimated to be issued pursuant to these performance share units at the end of the performance period is a total of 196,495 shares. If the maximum thresholds are met at the end of the performance period, a maximum of 225,778 total shares could be issued pursuant to these performance share units. If the minimum performance thresholds are not met, 40,408 shares would be issued at the end of the performance period.

2012 Performance Share Units

During the year ended December 31, 2012, the Company granted 60,365 performance share units with a grant date fair value of $39.0 million, based on a weighted average grant date fair value per share of $645.86. The actual number of shares to be issued will be determined upon completion of the performance period which ends December 31, 2014.

At June 30, 2014, there were 57,927 unvested 2012 performance share units outstanding, net of performance share units that were forfeited or vested since the grant date. As of June 30, 2014, the number of shares estimated to be issued pursuant to these performance share units at the end of the performance period is a total of 98,566 shares. If the maximum performance thresholds are met at the end of the performance period, a maximum of 115,854 total shares could be issued pursuant to these performance share units. If the minimum performance thresholds are not met, 36,173 shares would be issued at the end of the performance period.

Stock Options - Other than Stock Options Assumed in Acquisitions

The disclosures in this paragraph do not include employee stock options assumed in acquisitions (described below). During the six months ended June 30, 2014, stock options were exercised for 4,700 shares of common stock with a weighted average exercise price per share of $22.47 and an aggregate intrinsic value of $5.8 million. As of June 30, 2014, the aggregate number of shares subject to stock options outstanding and exercisable was 4,300, with a weighted average exercise price per share of $22.64, a weighted average remaining term of 0.8 years and an aggregate intrinsic value of $5.1 million.

Employee Stock Options Assumed in Acquisitions

The Company assumed vested and unvested employee stock options as part of the acquisitions completed in the second quarters of 2013 and 2014. The following table summarizes the activity of these assumed employee stock options for the six months ended June 30, 2014:



Assumed Employee Stock Options	Number of Shares		Weighted Average Exercise Price			Aggregate Intrinsic Value (in thousands)			Weighted Average Remaining Contractual Term (in years)
Balance, December 31, 2013	128,708			$	335.83		$	106,386	6.9
Assumed in acquisition	10,520			$	122.75
Exercised	(28,933	)		$	319.40
Forfeited	(172	)		$	452.47
Balance, June 30, 2014	110,123			$	319.61		$	97,282	6.7
Vested and exercisable as of June 30, 2014	76,412			$	269.43		$	71,336	5.9
Vested and exercisable as of June 30, 2014 and expected to vest thereafter, net of estimated forfeitures	108,387			$	318.09		$	95,913	6.6

The aggregate intrinsic value of employee stock options assumed in acquisitions that were exercised during the six months ended June 30, 2014 was $28.1 million. During the six months ended June 30, 2014, assumed unvested employee stock options vested for 15,363 shares of common stock with an acquisition date fair value of $6.5 million.

For the three and six months ended June 30, 2014, the Company recorded stock-based compensation expense related to these unvested assumed employee stock options of $2.7 million and $6.8 million, respectively, and $11.0 million for the three months ended June 30, 2013. As of June 30, 2014, there was $17.0 million of total future compensation costs related to unvested assumed employee stock options to be recognized over a weighted-average period of 2.5 years.