In the first nine months of 2021, our board of directors granted 577,500 restricted stock units (“RSUs”) to employees under our 2014 Incentive Plan for which vesting is based solely on continuous employment over the requisite service period. 536,000 of the RSUs vest at 33% per year at each anniversary of the grant date over the next three years, 37,000 of the RSUs vest at 50% per year at each anniversary of the grant date over the next two years, and 4,500 of the RSUs vest at 25% on each of the second and third anniversaries of the grant date and 50% on the fourth anniversary of the grant date. The weighted average grant date fair value for these RSUs was $47.56 per unit, which was based on the closing stock price on the respective grant dates.

In the first nine months of 2021, our board of directors granted 37,000 RSUs to employees under our 2014 Incentive Plan for which vesting is based on the Company’s achievement of certain performance targets over a two-year period (“performance condition”) as well as continued employment during the performance period. Assuming continued employment and if the performance vesting condition is achieved, the awards will vest on the second anniversary of the grant date. The actual number of shares of common stock that may be earned ranges from zero to 120% of the RSUs granted. The weighted average grant date fair value for these RSUs was $40.81 per unit, which was based on the closing stock price on the grant date.

In the first nine months of 2021, our board of directors granted 188,000 RSUs to employees under our 2014 Incentive Plan, that cliff vest on the third anniversary of the grant date based on the Company’s level of achievement of performance goals relating to return on invested capital over a three-year period (“performance condition”) as well as continued employment during the performance period. The total number of shares of common stock that may be earned from the performance condition ranges from zero to 200% of the RSUs granted. The number of shares earned from the performance condition may be further increased by 10% or decreased by 10% based on the Company’s total shareholder return relative to a peer group during the performance period (“market condition”). The average grant date fair value for these RSUs, with consideration of the market condition, was $47.85 per unit, which was determined using the Monte Carlo simulation model using the following assumptions:

Expected volatility (company)	51.3%
Expected volatility (peer group median)	42.9%
Correlation between the Company and peer group median	0.6
Expected dividend yield	0.0%
Risk-free rate	0.3%

The expected volatilities and correlation are based on the historical daily returns of our common stock and the common stocks of the constituents of the Company’s peer group over the most recent period equal to the measurement period. The expected dividend yield is based on our history of not paying regular dividends in the past and our current intention to not pay regular dividends in the foreseeable future. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant and has a term equal to the measurement period.