The agencies said they had found no evidence that the market decline was caused by so-called fat finger trading errors, or by computer hacking or terrorist activity. They added, however, “we cannot completely rule out these possibilities.”
Oh-Gee, no kidding!
http://www.nytimes.com/2010/05/19/business/19crash.html
Let me guess...it wasn't a "Fat Finger" error in trading at all; it was more like a ramping-up on the High Frequency Trading (computer trading algorithm) selling 'Short' which caused the stock drop.
http://www.youtube.com/user/MaxKeise.../0/2-PihbVN6O4