Facebook shareholders who held onto their stock during more than a year of disappointing performance following the company's May 2012 IPO were finally rewarded last month. In August, the company's stock price first reached, and then exceeded, its IPO valuation of $38 a share.

At least one investor has made a tidy profit from the recent gains. Mail.ru, a Russian internet services company, announced Thursday that it had cashed out its remaining Facebook shares, reportedly netting about $525 million.

Mail.ru invested about $200 million in Facebook in 2009. The company sold some of its shares in the IPO, as did Peter Thiel, Facebook's earliest investor. It sold the remaining 14.2 million shares, about 0.6 percent of Facebook's outstanding shares, in July and August, the company said.

Facebook's IPO was plagued by technical glitches, and its stock lost half of its value over the next few months. But it has rebounded impressively in the last year as investors became more confident in the social network's commitment to mobile. Russian billionaire Alisher Usmanov, part-owner of Mail.ru, still retains a personal stake in Facebook of an undisclosed number of shares, according to The New York Times.

At time of writing, Facebook's stock stood at $44.37, up more than three percent in Friday trading.

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