Facebook chief executive Mark Zuckerberg reaped a 3.3 billion dollar (£1.98 billion) gain last year by exercising stock options in the social networking company he founded at Harvard University.
The windfall saddled Mr Zuckerberg with a huge tax bill, even though he limited his Facebook salary to just 1 dollar (60p), according to documents filed yesterday.
It marks the second straight year that Mr Zuckerberg has realised a huge gain on the holding that he has accumulated in Facebook since he started the company in 2004. In 2012, he made 2.3 billion dollars(1.4 billion) off his stock options.
Mr Zuckerberg, 29, has now exhausted his supply of stock options after exercising 60 million of them last year a price of 6 cents (3.5p) per share.
He then sold 41.35 million shares for 55.05 dollars (£33) apiece in December, primarily to pay for his tax bill on the gains.
Mr Zuckerberg and his wife, Priscilla Chan, also donated 18 million Facebook shares to a Silicon Valley non-profit organisation.
Even after selling and donating so much Facebook stock, Zuckerberg still owns 426.3 million Facebook shares currently worth 25.7 billion dollars (£15.4 billion).
The stock has more than doubled in value during the past year as Mr Zuckerberg fulfilled his promise to sell more ads on the smartphones and tablet computers that bring in most of the traffic to Facebook's social networking service.
The Menlo Park, California, company now gets more than half of its ad revenue from mobile devices, up from 23% at the beginning of last year.
Like many company founders who have become wealthy off their early stakes, Mr Zuckerberg asked Facebook to limit his annual salary to 1 dollar annually.
Besides that token sum, he also received perquisites valued at 653,164 dollars (£392,000).
All but 3,000 dollars (£1,800) of that amount went toward Mr Zuckerberg's bills for personal travel on chartered jets.
Excluding stock option gains, Mr Zuckerberg's total compensation last year plunged 67% from nearly 2 million dollars £1.2 million) in 2012.