The weightedaverage grantdate fair value per share of the Tranche 1 options granted during
fiscal years 2009, 2008 and 2007 was $9.20, $3.56 and $2.57, respectively. The fair value of the Tranche 1 options was estimated on the date of grant using the BlackScholesMerton optionpricing model. Weightedaverage key assumptions used in
estimating the grantdate fair value of the options are as follows:









For the year ended December 31, 


2009 

2008 

2007 
Expected dividend yield 

0% 

0% 

0% 
Expected volatility 

34.79% 

25.00% 

25.00% 
Riskfree interest rate 

2.90% 

3.01% 

4.52% 
Expected term (years) 

6.5 

6.6 

6.6 
Forfeiture rate 

11.00% 

5.00% 

5.00% 
Fair value per share of underlying shares 

$14.89 

$11.38 

$7.36 
The expected term of the time vesting option was based upon the “simplified” methodology prescribed by SAB No. 107 (“SAB
107”). The expected term is determined by computing the mathematical mean of the average vesting period and the contractual life of the options. The Company utilized the simplified method for options granted during the years ended December 31,
2009, 2008 and 2007 due to the lack of historical exercise data necessary to provide a reasonable basis upon which to estimate the term. The Company considered the historical and implied volatility of publiclytraded companies within the
Company’s industry. Ultimately, the Company utilized the implied volatility to calculate the fair value of the options as it provides a forwardlooking indication and may offer insight into expected industry volatility. The riskfree interest
rate is based on the yield for a U.S. Treasury security having a maturity similar to the expected life of the related grant. The forfeiture rate is based on the Company’s estimate of forfeitures by plan participants based on historical
forfeiture rates. The dividend yield is based on management’s judgment with input from the Company’s Board of Directors.
In December 2007, the SEC issued SAB No. 110 (“SAB 110”). SAB 110 addresses the method by which a company would determine the
expected term of its “plain vanilla” share options. The expected term is a key factor in measuring the fair value and related compensation cost of sharebased payments. Under SAB 107, companies were allowed to apply a
“simplified” method in developing an estimate of the expected term. The use of the simplified method under SAB 107 expired on December 31, 2007. SAB 110 permits entities to continue to use the simplified method under certain
circumstances, including when a company does not have sufficient historical data surrounding share option exercise experience to provide a reasonable basis upon which to estimate expected term and during periods prior to its equity shares being
publicly traded. The Company concluded that it will continue to use the simplified method until sufficient historical data becomes available.
Under the fair value recognition provisions of ASC 718, the Company recognizes sharebased compensation net of an estimated forfeiture rate
and therefore only recognizes compensation cost for those shares expected to vest over the service period of the award. The Company has estimated its forfeitures based on historical experience. During the three months ended March 31, 2009, the
Company revised its forfeiture rate from 5% to 11% based upon the actual rate of forfeitures by plan participants. As a result, the Company recorded a reduction to its noncash compensation expense of $335 during the three months ended
March 31, 2009.
During the three months
ended September 30, 2009, the Company canceled an award issued to one employee on May 21, 2009 and concurrently issued a new award with different vesting terms. The Company accounted for this transaction as a modification under ASC 718, which
resulted in $470 of additional value. The Company will expense the remaining unrecognized compensation expense of $524 over the vesting period of the new award.
The Board determined that the exercise price of the options granted on September 4, 2009 was established at less than the fair market
value of the underlying shares. The exercise price of these options was reset on
F51