It is the second straight year that Zuckerberg has realized a huge gain on the holding that he has accumulated in Facebook since he started the company in 2004. Last year he made $2.3 billion off his stock options. However he has now apparently exhausted his supply of stock options after exercising 60 million of them last year a price of 6 cents per share. He then sold 41.35 million shares for $55.05 apiece in December, primarily to pay for his tax bill on the gains.
Zuckerberg and his wife, Priscilla Chan, also donated 18 million Facebook shares to a Silicon Valley nonprofit. The December gift, then valued at nearly $1 billion, landed the couple at the top of The Chronicle of Philanthropy's annual list of the most generous Americans.
Zuckerberg still owns 426.3 million Facebook shares currently worth $25.7 billion. The stock has more than doubled in value during the past year.