The losses in the past 11 trading days have taken 8.24 percent off the NASDAQ index, 6.1 percent from the DJIA, and cost 5.11 percent for the S&P500.
While such severe reversals are not usual, they are not unknown. Some 120 of the 2020 closes since January 2000 lost more than 5 percent over an eleven day span. Of these, seven are clustered in January 2003.
The DJIA shows the same pattern for losses deeper than six percent: 59 since 2000 of which five occurred in January 2003.
The NASDAQ, which lost more than eight percent so far this year, had 12 other such declines since 2000, and again these all took place in the month of January.
DJIA -. 28 percent
NASDAQ - .95 percent
S&P500 -. 56 percent