SAN FRANCISCO (AP) – Facebook CEO Mark Zuckerberg reaped a $3.3 billion gain last year by exercising stock options in the social networking company that he founded in a Harvard dorm room.

Facebook Inc. spelled out the windfall in regulatory documents filed Monday. It marks the second straight year that Zuckerberg has realized a huge gain from stock options. In 2012, he made $2.3 billion off his stock options.

The documents show Zuckerberg had no stock options remaining after exercising 60 million of them last year at a price of 6 cents per share. He then sold 41.35 million shares for $55.05 apiece in December primarily to cover his taxes.

The 29-year-old Zuckerberg still owns 426.3 million Facebook shares currently worth $25.7 billion.

Facebook paid Zuckerberg a $1 salary last year.