We recognized total stock-based compensation expense of $14.7 million and $11.0 million during the three months ended May 31, 2022 and May 31, 2021, respectively. During the nine months ended May 31, 2022 and May 31, 2021, we recognized total stock-based compensation expense of $40.6 million and $33.4 million, respectively. As of May 31, 2022, $121.1 million of total unrecognized compensation expense related to non-vested awards is expected to be recognized over a weighted average period of 3.1 years. There was no stock-based compensation capitalized as of May 31, 2022 and May 31, 2021.

During the nine months ended May 31, 2022, we granted 302,952 stock options under the FactSet Research Systems Inc. Stock Option and Award Plan, as Amended and Restated (the "LTIP") with a weighted average exercise price of $434.64 to existing employees of FactSet, using the lattice-binomial option-pricing model. The majority of the stock options granted during the nine months ended May 31, 2022 are related to the annual employee grant on November 1, 2021 under the LTIP. The stock option awards granted on November 1, 2021 vest 20% annually on the anniversary date of the grant and are fully vested after five years, expiring ten years from the date of grant. As of May 31, 2022, we had 4.7 million share-based awards available for grant under the LTIP.

We utilize the lattice-binomial option-pricing model ("binomial model") to estimate the fair value of new employee stock option grants. The binomial model is affected by our stock price, as well as assumptions regarding several variables, which include, but are not limited to, our expected stock price volatility over the term of the awards, interest rates, option forfeitures and employee stock option exercise behaviors, to determine the grant date stock option award fair value.

The weighted average estimated fair value of employee stock options granted on November 1, 2021 was determined using the binomial model with the following weighted average assumptions:


November 1, 2021 Grant Details
Risk-free interest rate	0.07% - 1.56%

Expected life (years)	6.91

Expected volatility	24.4	%

Dividend yield	0.85	%

Estimated fair value	$102.40
Exercise price	$434.82
Fair value as a percentage of exercise price	23.5	%

The FactSet Research Systems Inc. Non-Employee Directors’ Stock Option and Award Plan as Amended and Restated (the "Director Plan") provides for the grant of share-based awards, including stock options, to non-employee directors of FactSet. The expiration date of the Director Plan is December 19, 2027. The non-qualified stock options granted to directors vest 100% after three years on the anniversary date of the grant and expire seven years from the date the options were granted. As of May 31, 2022, we had 227,348 shares available for future grant under the Director Plan.

On January 18, 2022, we granted 6,329 stock options under the Director Plan to our non-employee directors, using the Black-Scholes option-pricing model with the following assumptions:


January 18, 2022 Grant Details
Risk-free interest rate	1.53	%

Expected life (years)	5.7

Expected volatility	26.3	%

Dividend yield	0.72	%

Estimated fair value	$109.11
Exercise price	$428.71
Fair value as a percentage of exercise price	25.5	%

During the nine months ended May 31, 2022, we granted 71,933 non-performance based restricted stock units ("RSUs") and 30,704 performance-based restricted stock units ("PSUs"; RSUs and PSUs, collectively, "Restricted Stock Awards") under the LTIP. The Restricted Stock Awards granted under the LTIP during the nine months ended May 31, 2022 had a weighted average grant date fair value of $418.16.

Restricted Stock Awards are subject to continued employment over a specified period and entitle the holders to shares of common stock as the Restricted Stock Awards vest over time. Vesting of the shares underlying the PSUs are also subject to achieving certain specified performance levels during the measurement period subsequent to the date of grant. The Restricted Stock Award holder is not entitled to dividends declared on the underlying shares while the stock subject to the Restricted Stock Award is unvested. The grant date fair value of Restricted Stock Awards is measured by reducing the grant date price of the common stock by the present value of the dividends expected to be paid on the underlying stock during the requisite service period, discounted at the appropriate risk-free interest rate. The expense associated with Restricted Stock Awards is amortized over the vesting period.

The majority of the Restricted Stock Awards granted during the nine months ended May 31, 2022 were related to the annual employee grant on November 1, 2021. With respect to the November 1, 2021 grant, RSUs granted vest 20% annually on the anniversary date of grant and are fully vested after five years and PSUs granted cliff vest on the third anniversary of the grant date, subject to the achievement of certain performance metrics. Substantially all the other RSUs granted during the nine months ended May 31, 2022 vest one-third annually on the anniversary date of grant and are fully vested after three years.

The Director Plan provides for the grant of share-based awards, including RSUs, to non-employee directors of FactSet. On January 18, 2022, we granted 1,629 RSUs to our directors that vest 100% on the first anniversary of the grant date. The RSUs granted under the Director Plan during the nine months ended May 31, 2022 had a weighted average grant date fair value of $425.49.

Shares of FactSet common stock may be purchased by eligible employees under the FactSet Research Systems Inc. Employee Stock Purchase Plan, as Amended and Restated (the "ESPP") in three-month intervals. The purchase price is equal to 85% of the lesser of the fair market value of our common stock on the first day or the last day of each three-month offering period. Employee purchases may not exceed 10% of their gross compensation, and there is a $25,000 contribution limit per employee during an offering period. Shares purchased through the ESPP cannot be sold or otherwise transferred for 18 months after purchase. Dividends paid on shares held in the ESPP are used to purchase additional ESPP shares at the market price on the dividend payment date.

During the three months ended May 31, 2022, employees purchased 9,904 shares through the ESPP at a weighted average price of $328.85 compared with 10,621 shares at a weighted average price of $267.02 for the three months ended May 31, 2021. During the nine months ended May 31, 2022, employees purchased 27,321 shares through the ESPP at a weighted average price of $336.22 compared with 29,418 shares at a weighted average price of $271.94 for the nine months ended May 31, 2021. Stock-based compensation expense related to the ESPP was $0.6 million for the three months ended May 31, 2022 and $0.5 million for the three months ended May 31, 2021. Stock-based compensation expense related to the ESPP was $1.7 million for the nine months ended May 31, 2022 and $1.5 million for the nine months ended May 31, 2021. As of May 31, 2022 the ESPP had 111,635 shares reserved for future issuance.