Mark Zuckerberg's Net Worth Falls by $7.2 Billion

NEW YORK (CNNMoney) -- The value of Facebook CEO Mark Zuckerberg's stake in the company he founded has plunged $7.2 billion since its initial public offering.

Zuckerberg was worth $19.1 billion, based on the IPO price of $38 a share back in May. He sold 30 million shares on the stock's debut day in order to raise cash to pay taxes, but he still had 503 million shares at the conclusion of the IPO.

But as of midday Friday, Zuckerberg's stake is now worth $11.98 billion.

To put the $7 billion drop in context, the estimated net worth of Google chairman Eric Schmidt, based on his ownership stake in the search giant, is $5.5 billion. So you could say that Zuckerberg has lost more than a Schmidt-load of money.

Still, nobody should shed any tears for Zuckerberg. Being worth just under $12 billion is still enough to make him among the 72 richest people in the world, according to the most recent rankings from Forbes.

Facebook shares closed barely above the IPO price the first day of trading and have steadily lost ground ever since. The company released its first earnings report since the IPO on Thursday and investors were disappointed. Facebook hit an all-time low Friday.

Of course Zuckerberg isn't the only one who has taken a hit from Facebook's fall. Sheryl Sandberg, the company's chief operating officer, had just under a $1.6 billion stake in the company at the time of the IPO, but has seen the value of that stake fall to $980 million with the latest slide.

Dustin Moskovitz, one of the co-founders of Facebook and the second largest individual shareholder after Zuckerberg, lost $1.9 billion of his $5.1 billion stake in the company. Another former executive from its early days, Sean Parker, the third largest individual shareholder, has lost nearly $1 billion of his $2.6 billion stake at the time of the IPO.

The CEOs of other social media companies have also watched their net worth plunge since their IPOs. Zynga CEO Mark Pincus has seen the value of his stake fall by 70% since the online game developer's December IPO.

The slide in shares of online discount site Groupon have also hit CEO Andrew Mason's stake very hard. The stock is down 65% since its debut.

But neither Pincus or Mason had a net worth remotely approaching Zuckerberg's -- both had stakes in their companies worth just more than $900 million at the time their IPO's priced. That means that Mason's net worth has tumbled by $610.1 million, while Pincus has lost $650.9 million in Zynga's decline.

Pincus also had 4.3 million shares of Facebook after the IPO there, so he lost another $61.2 million in the Facebook stock slide since then, taking his Facebook holdings down to about $102.4 million.

But one social media CEO who has done well since his IPO is LinkedIn's Jeffrey Weiner. Shares of the company have more than doubled since the May 2011 IPO, although they are off the highs they hit this past May during the hype surrounding the Facebook IPO.

-- Staff writer Ben Rooney contributed to this report