On January 1, the company granted 150,000 stock options to key employees. Each option allows an employee to buy one share of $1 par common stock for $25, which was the market price of the shares on the grant date of January 1. In order to be able to exercise the options, the employees must remain with the company for three entire years. It is estimated that the fair value of each option on the date of grant was $4. At the end of three years, all of the options were exercised when the market price of the shares was $38 per share. Assume that the stock-based compensation plan is performance based. As of the end of the first year, the number of options that are probable to vest is 150,000. At the end of the second year, the number of options that are probable to vest is 120,000. The options have a 3-year service period.
What is the compensation expense at the end of the second year?