Maybe Gates simply timed his exit and Microsoft's stock price was going to fall anyway. Classic endogeneity problem: http://en.wikipedia.org/wiki/Endogeneity_

Maybe Gates simply timed his exit and Microsoft's stock price was going to fall anyway. Classic endogeneity problem: http://en.wikipedia.org/wiki/Endogeneity_(economics) http://en.wikipedia.org/wiki/Endogeneity_(economics)