On May 6, 2010, just a half hour before futures close, the Dow Jones Industrial Average plunged by 998.50 points on an intra-day loss of 9.2%. Although they recovered quickly it was the biggest intra-day fall ever. One of the rumors on the street was that some Equities Trader accidentally oversold some Procter & Gamble stock at a billion vs a million. The real reason is not yet known but some speculate it has to do with a mismatch in rules between the older New York Stock Exchange and younger electronic trading exchanges. In any event that was pretty darn scary - like Gordon Gekko scary.
Coincidentally, while all this is happening in real life the new Wall Street Movie, Money Never Sleeps, is getting released on September 24th. Ha!
Here's the trailer on You Tube:
http://www.youtube.com/watch?v=lPCSAAtyLW8