That means he's lost $4.5m (£2.74m) per minute since midnight, according the Bill Gates Net Worth Page. But don't shed too many tears. Gates' worth has actually climbed nearly 40 percent in the past year, and he's still is worth more than all the gold in Fort Knox.
Michael Dell had the second-worst fall in his net worth, losing nearly $2bn (£1.2bn) to $11.5bn (£7bn) Monday, as his stock slid a whopping 18 points to 100. He's lost $3.3bn (£2bn) since last Wednesday, according to the Nordby International Inc. CEO Wealth Meter.
And poor Yahoo! executive Jerry Yang was bounced from the billionaire club. He was a member Friday morning, but an 11-point drop in Yahoo! shares over the past two days caused his worth to tumble to a piddly $793m (£483m).
Others taking a paper-worth pounding included Amazon.com CEO Jeff Bezos, who's lost more than 34 percent of his money since Wednesday, slipping to $1.65bn (£1bn). On Monday alone, Amazon.com stock plummeted $22 9/64 to $83, a loss of more than 20 percent.
At least one high-profile CEO seemed to come out relatively unscathed -- at first glance. Because he owns only one Apple share, interim CEO Steven Jobs lost just three bucks. But he didn't fare so well with Pixar, where he owns 30,000,001 shares, according to SEC filings. The value of those shares lost $28 (£17m) Monday.