Facebook founder Mark Zuckerberg sold shares to pay tax bill Facebook founder Mark Zuckerberg, 28, has paid a massive tax bill. FACEBOOK chief executive Mark Zuckerberg reaped a gain of nearly $US2.3 billion ($A2.24 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 on Friday saddled Zuckerberg, 28, with a massive tax bill. He raised the money to pay it by selling 30.2 million Facebook Inc shares for $US38 apiece, or $US1.1 billion, in the IPO. Facebook's stock hasn't closed above $US38 since the IPO was completed last May. The shares gained 71 US cents on Friday to close at $26.85. The 29 per cent decline from Facebook's IPO price has cost Zuckerberg nearly $US7 billion on paper, based on the 609.5 million shares of company stock that he owned as of March 31, according to the regulatory filing. His current stake is still worth $US16.4 billion. Zuckerberg, who started Facebook in his Harvard University dorm room in 2004, has indicated he has no immediate plans to sell more stock. The exercise of Zuckerberg's stock options and his subsequent sale of shares in the IPO had been previously disclosed. The proxy statement filed to announce Facebook's June 11 shareholder meeting is the first time that the magnitude of Zuckerberg's stock option gain had been quantified. The proxy also revealed that Zuckerberg's pay package last year rose 16 per cent because of increased personal usage of jets chartered by the company as part of his security program. Zuckerberg's compensation last year totalled nearly $US2 million, up from $US1.7 million last year. Of those amounts, $US1.2 million covered the costs of Zuckerberg's personal air travel last year, up from $US692,679 in 2011. If not for the spike in travel costs, Zuckerberg's pay would have declined by 17 per cent. His salary and bonus totalled $US769,306 last year versus $US928,833 in 2011.