Facebook shares climbed to a new high on Tuesday, catapulting chief operating officer Sheryl Sandberg onto the roster of tech billionaires. Shares of the world's leading social network closed the Nasdaq trading day at $58.51, shedding a few cents in after-hours trade. Sandberg owns about $750 million worth of Facebook stock and is said to have sold about $300 million worth of shares since the California-based company became a publicly traded company in May of 2012. The 44-year-old former Google executive is also reported to have stock options for nearly five million shares that began vesting last year. The social media giant started by Mark Zuckerberg, which now has more than 1.1 billion users around the globe, had a rocky debut after it went public at $38 a share with a valuation of $16 billion. Facebook shares dropped below $20 during the ensuing months and only climbed back over their offer price in July of last year. Zuckerberg, who will turn 30 in May, has a personal fortune estimated at about $19 billion. Facebook will release its quarterly earnings figures next week.