According to a filing with the SEC on Tuesday, Thiel sold roughly three-quarters of his remaining Facebook stock on Nov. 20, netting him $28.7 million.
The PayPal co-founder and venture investor was an early backer of Facebook, investing $500,000 in 2004, gaining a board seat that he still holds and 2.5 percent of the company at the time of the IPO.
While Thiel is in no way hurting for cash, he would have been much wealthier had he stashed those Facebook shares away after the 2012 IPO.
Instead, as part of a pre-arranged plan, he sold almost 80 percent of his stake within a few months of the IPO at an average price of less than $20 a share. Facebook is now trading at $180.50.