James Breyer and Accel Partners

Breyer, with Accel Partners, courted Zuckerberg hard and eventually got him to agree to take a $12.7 million investment that valued the company at $93 million. What a bet that turned out to be. Accel already sold $2.1 billion worth of stock into the IPO, so selling more soon doesn't seem like an obvious move. It still owns 35.7 million Class A shares, and 7.9 million Class B shares.