Mark Zuckerberg ended last Friday with his Facebook holdings valued at more than $19 billion.
He followed that up with a surprise wedding, marrying his longtime girlfriend at his place in Palo Alto.
This week is a different story for Facebook and its CEO Zuclerberg. Shares of the social network began to trade under its $38 IPO price for the first time on its second day in the public market.
Facebook shares opened Monday at $35.75, and at one point they went down as much as $33.
Zuckerberg, who owns 503.6 million shares of his company, saw the value of the Facebook shares he holds slide from $19.25 billion at the end of the day Friday to $18 billion at the start of regular trading Monday and then all the way down to about $16.62 billion.
At the close of the trading day, Facebook had a stock price of $34.03, down almost 11% from its close Friday. At that price, Zuckerberg's Facebook holdings are worth about $17.14 billion.
That's a loss of about $2.11 billion. Ouch.