The reason for exercising early is (as GrthzGd noted in #msg-70228670) to start the clock on LT capitals-gains treatment for the difference between the eventual sale price and the exercise price. In the case we’re discussing (MNTA’s Chairman), the exercised options did not expire until 2018.
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”