Dustin Moskovitz, one of Facebook's founders, sold off 450,000 of his shares in the company over the last few days.
Moskovitz, who left Facebook in 2008 to pursue other goals, sold the shares at prices between $19.38 and $20, according to Bloomberg. That means the 28-year-old billionaire earned at least $8.7 million in exchange for his shares.
Moskovitz's move was revealed in a Facebook filing with the Securities and Exchange Commission on Tuesday.
With the sale, Moskovitz still has 7.05 million Class A Facebook shares left, currently worth about $135 million. In all, he says, he has more than 100 million shares.
But Moskovitz isn't the only notable Facebook stockholder to unload parts of his shares recently.
Earlier this week, news also broke that Peter Thiel, one of the first people to invest in the social network, sold off most of his shares in the company.