(4)   Stock-Based Compensation

Liberty grants, to certain of its directors, employees and employees of its subsidiaries, restricted stock, restricted stock units (“RSUs”) and stock options to purchase shares of its common stock (collectively, "Awards"). The Company measures the cost of employee services received in exchange for an equity classified Award (such as stock options and restricted stock) based on the grant-date fair value (“GDFV”) of the Award, and recognizes that cost over the period during which the employee is required to provide service (usually the vesting period of the Award). The Company measures the cost of employee services received in exchange for a liability classified Award based on the current fair value of the Award, and remeasures the fair value of the Award at each reporting date.

Included in the accompanying condensed consolidated statements of operations are the following amounts of stock-based compensation, as discussed below:

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Liberty—Grants of stock options

Awards granted during the six months ended June 30, 2019 are summarized as follows:

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In addition to the stock option grants to the Liberty CEO and in connection with his employment agreement, during the six months ended June 30, 2019, Liberty granted 40 thousand and 72 thousand RSUs of Series C Liberty Braves common stock and Series C Liberty Formula One common stock, respectively, of which 38 thousand and 60 thousand, respectively, were performance-based. Such RSUs had a GDFV of $27.73 per share and $33.94 per share, respectively, at the time they were granted. The time-based RSUs cliff vested on March 11, 2019 and the performance-based RSUs cliff vest in one year, subject to satisfaction of certain performance objectives. Performance objectives, which are subjective, are considered in determining the timing and amount of the compensation expense recognized. As the satisfaction of the performance objectives becomes probable, the Company records compensation expense. The probability of satisfying the performance objectives is assessed at the end of each reporting period.

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The Company did not grant any options to purchase Series A or Series B Liberty SiriusXM, Liberty Braves or Liberty Formula One common stock during the six months ended June 30, 2019.

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Liberty calculates the GDFV for all of its equity classified awards and the subsequent remeasurement of its liability classified and certain performance-based awards using the Black-Scholes Model. Liberty estimates the expected term of the Awards based on historical exercise and forfeiture data. The volatility used in the calculation for Awards is based on

the historical volatility of Liberty common stock and the implied volatility of publicly traded Liberty options. Liberty uses a zero dividend rate and the risk-free rate for Treasury Bonds with a term similar to that of the subject Awards.

Liberty—Outstanding Awards

The following tables present the number and weighted average exercise price ("WAEP") of Awards to purchase Liberty common stock granted to certain officers, employees and directors of the Company and certain Awards of employees of Lions Gate Entertainment Corp. (formerly employees of Starz).

Liberty SiriusXM

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Liberty Braves

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Liberty Formula One

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As of June 30, 2019, the total unrecognized compensation cost related to unvested Awards was approximately $28 million. Such amount will be recognized in the Company's condensed consolidated statements of operations over a weighted average period of approximately 1.4 years.

As of June 30, 2019, Liberty reserved 13.1 million, 1.4 million and 9.2 million shares of Series A and Series C common stock of Liberty SiriusXM, Liberty Braves and Liberty Formula One, respectively, for issuance under exercise privileges of outstanding stock Awards.

SIRIUS XM Holdings — Stock-based Compensation

SIRIUS XM Holdings granted various types of stock awards to its employees during the six months ended June 30, 2019. As of June 30, 2019, SIRIUS XM Holdings has approximately 252 million options outstanding of which approximately 151 million are exercisable, each with a WAEP per share of $4.32 and $3.72, respectively. The aggregate intrinsic value of SIRIUS XM Holdings options outstanding and exercisable as of June 30, 2019 is $354 million and $284 million, respectively. During the six months ended June 30, 2019, SIRIUS XM Holdings granted approximately 12 million nonvested RSUs with a GDFV per share of $5.84. In addition, 48 million nonvested RSUs with a GDFV per share of $5.83 were granted during the six months ended June 30, 2019 in connection with the Pandora acquisition. The stock-based compensation expense related to SIRIUS XM Holdings was $57 million and $36 million for the three months ended June 30, 2019 and 2018, respectively, and $106 million and $70 million for the six months ended June 30, 2019 and 2018, respectively. In addition, the acquisition and other related costs recognized by SIRIUS XM Holdings during the six months ended June 30, 2019 includes $21 million of stock-based compensation. As of June 30, 2019, the total unrecognized compensation cost related to unvested SIRIUS XM Holdings stock options and RSUs was $406 million. The SIRIUS XM Holdings unrecognized compensation cost will be recognized in the Company's condensed consolidated statements of operations over a weighted average period of approximately 1.9 years.