The company stock fortunes of some of the richest entrepreneurs in America got skinned over the last two weeks, as stocks sank to a two-month low and talk picked up that a correction was in the works.

Amazon’s Jeff Bezos lost $4 billion alone, on paper at any rate. Google CEO Larry Page lost $1.4 billion, as did Google co-founder Sergey Brin. Facebook CEO and founder Mark Zuckerberg gave up $772 million.

USA Today estimated the value of their holdings based on SEC filings, FactSet ownership data, and their companies’ stock prices from July 24, when the S&P 500 SPY hit a high, to the close of Aug. 7. Stocks recovered some lost ground in Friday’s 1% rally.

For those companies with more than one share class — namely Google (which has three) and Facebook (two), the values of the non-traded stock were based on the price of the tradable shares.

Few of the tech stocks that have been leading the market were immune from the stock selloff over the last two weeks, which came on the heels of a generally well-received earnings season.

Investors ate up earnings from Facebook FB, Google GOOG, and especially Twitter TWTR. But that wasn’t enough to offset the triple blow to market confidence from Russia/Ukraine, Israel/Gaza and U.S./Iraq. Facebook, whose shares rallied 5.2% after earnings, gave up half that percent gain by Aug. 7.

Of course, to lose big you need to win big first.

Many of the tech titans, especially the newer ones, have their wealth tied up in the shares of just one company — the one they founded or ran. Bezos’ $4 billion paper loss is less than one-seventh of his $26 billion Amazon fortune. The bulk of that loss came in the session after Amazon reported a big quarterly loss.

And not every mogul was hit with red ink.

Two of Twitter’s biggest investors — founders Evan Williams and Jack Dorsey — are better off, to the tune of $239 million for Williams. They can chalk that gain up to Twitter’s nearly 20% stock surge the day after it posted surprisingly strong earnings.