Facebook CEO Reaped $2.3B Gain on Stock Options Facebook CEO Mark Zuckerberg reaped a gain of nearly $2.3 billion last year when he exercised 60 million stock options just before the online social networking leader's initial public offering. The windfall detailed in regulatory documents filed Friday saddled the 28-year-old Zuckerberg with a massive tax bill. He raised the money to pay it by selling 30.2 million Facebook Inc. shares for $38 apiece, or $1.1 billion, in the IPO. Facebook's stock hasn't closed above $38 since the IPO was completed last May. The shares gained 71 cents Friday to close at $26.85. The 29 percent decline from Facebook's IPO price has cost Zuckerberg nearly $7 billion on paper, based on the 609.5 million shares of company stock that he still owns. His current stake is still worth $16.4 billion.