I can't answer definitively, but I know, for myself, if I had helped grow a company that I really believed would be a disruptive success and my possible contributions to where it was going were reaching an end, I would want to exit gracefully in an expedient manner. Not only to allow for those that could take it further, but, if I had the means (which most in those positions do), to also give myself the opportunity to capitalize on the success by buying in the open market.

Sure, they have options, but those are finite and may be a lot less than they want to invest in the company. By leaving early they are able to buy uninhibited by blackouts or insider trading laws. This is at least something to consider.

And as just one last note, Peter is still with the company as Executive Co-Chairman.

Green