Joining a flock of investors heading for the exits, Facebook (FB) early investor and director Peter Thiel unloaded almost $400 million of stock in the embattled social network last week when lockup restrictions expired.

Despite the company’s post-IPO stumbles, Thiel has been handsomely rewarded for his early belief in Mark Zuckerberg’s Facebook. Thiel, a founder of eBay’s (EBAY) PayPal, sunk $500,000 into the new social network back in 2004, making him its earliest investor.

According to regulatory filings late Thursday, Thiel unloaded about 20.06 million shares of Facebook on August 16 and August 17 at an average price of $19.73. Those transactions netted Thiel $395.81 million.

Had Thiel sold that tranche Facebook’s lofty IPO price of $38 back in May, he would have made about $762 million.

But don’t feel too bad for Thiel, a partner at venture-capital firm Founders Fund, who has made more than $1 billion on his savvy support for a young Facebook.

Thiel also unloaded about 16.8 million shares for $638 million when Facebook went public in May.

Even after last week’s sale, Thiel still remains on Facebook’s board of directors and still owns stock in the company worth about $112 million.

Shares of Facebook bounced off all-time lows on Monday with a 5% rise to $20.01, but they retreated 1.65% to $19.69 Tuesday morning.

Facebook has lost about half of its value since the high-profile IPO amid persistent concerns about the social network’s ability to monetize its mobile business and attract advertisers in general.

Follow Matt Egan on Twitter @MattMEgan5