Company: ATRA
Filing Date: 2025-03-07
Form Type: 10-K
Source: 0000950170-25-035507
Chunk: 235

Company: Atara Biotherapeutics, Inc.
Filing Date: 2025-03-07
Form: 10-K
Item: Item 1B
Chunk 235
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91

        7.0

        $
        27

        Vested and expected to vest as of   December 31, 2024

        234,143

        $
        217.91

        7.0

        $
        27

        Exercisable as of December 31, 2024

        172,546

        $
        252.41

        6.7

        $
        9

      Aggregate intrinsic value represents the difference between the closing stock price of our common stock on December 31, 2024 and the exercise price of outstanding, in-the-money options. As of December 31, 2024, there was $4.7 million of unrecognized stock-based compensation expense related to stock options that is expected to be recognized over a weighted average period of 1.0 years. This excludes unrecognized stock-based compensation expense for performance-based stock options that were deemed not probable of vesting in accordance with U.S. GAAP. No options for shares of our common stock were exercised during the years ended December 31, 2024 and 2023. As we believe it is more likely than not that no stock option related tax benefits will be realized, we do not record any net tax benefits related to exercised options. 

125

The fair value of each option issued was estimated at the date of grant using the Black-Scholes valuation model. The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model and resulting weighted-average grant date fair values of stock options granted during the periods indicated: 

        Year ended December 31,

        2024

        2023

        Assumptions:

        Expected term (years)

        5.5

        5.8

        Expected volatility

        114.2
        %

        83.9
        %

        Risk-free interest rate

        4.0
        %

        4.2
        %

        Expected dividend yield

        0.0
        %

        0.0
        %

        Fair Value:

        Weighted-average estimated grant date fair value per share
         
        $
        9.20

        $
        65.50

        Options granted

        16,500

        187,756

        Total estimated grant date fair value
         
        $
        151,800

        $
        12,298,010