Assuming that the S&P 500 reaches 1260 or less tomorrow on 1/22/08, the S&P 500 would be nearly 5 standard deviations below its 200 day moving average.
No other events come close:
July 23, 2002 S&P at 4.26 SD below its 200 day MA
Sept 21, 2001 S&P at 3.43 SD below its 200 day MA
Oct 19, 1987 S&P at 3.64 SD below its 200 day MA
This time may be different but it would difficult to see the S&P 500 maintaining a distance of 5 standard deviations below its 200 day moving average for a prolonged period of time.
No other events come close:
July 23, 2002 S&P at 4.26 SD below its 200 day MA
Sept 21, 2001 S&P at 3.43 SD below its 200 day MA
Oct 19, 1987 S&P at 3.64 SD below its 200 day MA
This time may be different but it would difficult to see the S&P 500 maintaining a distance of 5 standard deviations below its 200 day moving average for a prolonged period of time.