Facebook board member and early investor Marc Andreessen has sold more than 900,000 of his shares in the company.
Andreessen, a co-founder of early web browser Netscape, runs capital firm Andreessen Horowitz with partner Ben Horowitz.
He is also an investor in Skype, Twitter, Groupon, and Airbnb.
Andreessen still owns more than 1.1 million shares of Facebook and the shares he ditched this week were part of a prearranged trading plan.
Spokespeople at Facebook and Andreessen Horowitz declined to comment.
Andreessen is known for his outspoken rants on Twitter, where he remains completely unfiltered. During a recent panel with Facebook’s Sheryl Sandberg he was asked why he appears to use Twitter more than Facebook.
“I believe I’m doing valuable competitive analysis,” Andreessen joked.