We compare the market values of executive stock option (ESO) trades with their Black & Scholes (1973) model values calculated following the major accounting standards, SFAS No. 123r and IFRS2. Our results show major underpricing compared to the traditional B&S method values. This should be considered while applying SFAS No. 123r and IFRS2 for estimating fair values. Especially time to expiration has a major influence on the undervaluation suggesting that the possibility of a change in corporate structure lowers the cost of ESOs to shareholders.