baker hughes , a ge company notes to consolidated and combined financial statements bhge 2017 form 10-k | 83 issuance pursuant to awards granted under the lti plan over its term which expires on the date of the annual meeting of the company in 2027 .a total of 53.7 million shares of class a common stock are available for issuance as of december 31 , 2017 .as a result of the acquisition of baker hughes , on july 3 , 2017 , each outstanding baker hughes stock option was converted into an option to purchase a share of class a common stock in the company .consequently , we issued 6.8 million stock options which are fully vested .each converted option is subject to the same terms and conditions as applied to the original option , and the per share exercise price of each converted option was reduced by $ 17.50 to reflect the per share amount of the special dividend pursuant to the agreement associated with the transactions .additionally , as a result of the acquisition of baker hughes , there were 1.7 million baker hughes restricted stock units ( rsus ) that were converted to bhge rsus at a fair value of $ 40.18 .stock-based compensation cost is measured at the date of grant based on the calculated fair value of the award and is generally recognized on a straight-line basis over the vesting period of the equity grant .the compensation cost is determined based on awards ultimately expected to vest ; therefore , we have reduced the cost for estimated forfeitures based on historical forfeiture rates .forfeitures are estimated at the time of grant and revised , if necessary , in subsequent periods to reflect actual forfeitures .there were no stock-based compensation costs capitalized as the amounts were not material .during the year ended december 31 , 2017 , we issued 2.1 million rsus and 1.6 million stock options under the lti plan .these rsus and stock options generally vest in equal amounts over a three-year vesting period provided that the employee has remained continuously employed by the company through such vesting date .stock based compensation expense was $ 37 million in 2017 .included in this amount is $ 15 million of expense which relates to the acceleration of equity awards upon termination of employment of baker hughes employees with change in control agreements , and are included as part of "merger and related costs" in the consolidated and combined statements of income ( loss ) .as bhge llc is a pass through entity , any tax benefit would be recognized by its partners .due to its cumulative losses , bhge is unable to recognize a tax benefit on its share of stock related expenses .stock options the fair value of each stock option granted is estimated using the black-scholes option pricing model .the following table presents the weighted average assumptions used in the option pricing model for options granted under the lti plan .the expected life of the options represents the period of time the options are expected to be outstanding .the expected life is based on a simple average of the vesting term and original contractual term of the awards .the expected volatility is based on the historical volatility of our five main competitors over a six year period .the risk-free interest rate is based on the observed u.s .treasury yield curve in effect at the time the options were granted .the dividend yield is based on a five year history of dividend payouts in baker hughes. .
[['', '2017'], ['expected life ( years )', '6'], ['risk-free interest rate', '2.1% ( 2.1 % )'], ['volatility', '36.4% ( 36.4 % )'], ['dividend yield', '1.2% ( 1.2 % )'], ['weighted average fair value per share at grant date', '$ 12.32']]
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Question: what is the expense which relates to the acceleration of equity awards upon termination of employment of baker hughes employees as a percentage of stock based compensation expense?
Answer: 40.5%