Zuckerberg’s tax bill estimated at $1.5 billion for 2011

If things work to plan, Facebook founder, chairman and CEO Mark Zuckerberg's share of the profit in his company's upcoming initial public offering would see him facing a tax bill of around $1.5 billion for 2011.

But that is not all Financial Times reports, that astronomical bill could be higher if the IPO is more successful than many analysts believe.

Currently, according to FT, the stock sells at $40 per share in private secondary markets – a level that would net Zuckerberg around $4.8 billion at the IPO. If the shares were  to rise to a level that would put Facebook's valuation at around $100 billion, the 27-year-old could net $6 billion.

The initial public offering documents that Facebook filed show last year it made $1 billion on $3.7 billion in revenue, making it more than twice as profitable as Google when it went public in 2004 and about as profitable as the CBS television network is today.

The company's Form S-1 SEC filing earlier this week, which revealed the IPO plans, said Zuckerberg would use "substantially all of the net proceeds" that he will receive upon the sale of an as-yet undisclosed number of shares in the IPO to "satisfy taxes that he will incur upon his exercise of an outstanding stock option to purchase 120,000,000 shares of our Class B common stock."

The 120 million fully vested options that Zuckerberg plans to exercise, would cost him 6¢ per share.