I wonder if the lock up for going public is more strict than when the company is being purchased for stock in a public company. E.g. Mark Cuban seemed to be able to use options to hedge his exposure to Yahoo: http://investmentxyz.blogspot.com/2006/05/cubans-collar-anat...
Broadcast.com went public July 18, 1998. Yahoo purchased BCST in April 1999 (or announced it then, not sure when it closed).
I'm guessing even if it were a potential issue, enough time had passed from the IPO, and it's unlikely the same restrictions apply to an acquisition. Cuban likely held his shares free and clear at that point.
A $1.4 billion collar would have drawn a lot of attention from the SEC, doubly so given the publicity and scale of the Yahoo transaction.
