Company: ATRA
Filing Date: 2025-03-07
Form Type: 10-K
Source: 0000950170-25-035507
Chunk: 268

Company: Atara Biotherapeutics, Inc.
Filing Date: 2025-03-07
Form: 10-K
Item: Item 7
Chunk 268
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 were no material changes from our estimates of accrued research and development expenses. We do not believe there is a reasonable likelihood that there will be a material change in the future estimates of accrued research and development expenses. However, if actual results are not consistent with our estimates, we may be exposed to changes in accrued research and development expenses that could be material or the accrued research and development expenses reported in our financial statements may not be representative of the actual economic cost of accrued research and development.

Stock-based Compensation 

We have stock-based compensation programs, which include an employee incentive plan, an inducement plan and an employee stock purchase plan. See Note 2 – “Summary of Significant Accounting Policies” and Note 10 – “Stockholders' Equity” in the Notes to Consolidated Financial Statements, included in Item 8. Financial Statements and Supplementary Data of this report for a complete discussion of our stock-based compensation programs. We account for stock-based compensation expense, including the expense for grants of restricted stock units (RSUs) and stock options that may be settled in shares of our common stock, based on the fair values of the equity instruments issued. The fair value is determined on the measurement date, which is generally the date of grant. The fair value of our RSUs is measured at the market price of our common stock on the measurement date. The fair value for our stock option awards is determined at the grant date using the Black-Scholes valuation model. 

Assumptions for the Black-Scholes valuation model used for employee stock awards include: 

•Expected term – We derived the expected term for employee stock awards using the “simplified” method (the expected term is determined as the average of the time-to-vesting and the contractual life of the options), as we have limited historical information to develop expectations about future exercise patterns and post vesting employment termination behavior. Expected term for non-employee awards is based on the remaining contractual term of an option on each measurement date.

•Expected volatility – In earlier periods, volatility was estimated using an average of our historical volatility and comparable public companies’ volatility for similar terms. Beginning in 2023, volatility is based solely on Atara's historical stock price volatility. 

•Expected dividend rate – We have not historically declared or paid dividends to our stockholders and have no plans to pay dividends; therefore, we have assumed an expected dividend yield of 0%.

•Risk-free interest rate – The risk-free interest rate is based on the yields of U.S. Treasury securities with expected terms similar to