While it looks as if the market is intent on going lower anyway into the close, the 2:45ish sudden 200 point meltdown was fascinating to watch. As they collared the market, as you would expect the normal flow stopped. As traders placed sell orders against S&P futures when the collars were lifted at 2:45 - BAM... a vacuum of sellers which the system could NOT handle. The discount to fair value on futures vs cash was breath taking! The chart below shows the high jinks on the Dow intraday at the time.