Russell 2000 falls 20%
Among the “big four” equity indexes, the small-cap Russell 2000 suffered the worst. For one of the few times in its 40+ year history, it lost more than 9% of its value in a single session.
That was enough to push the index more than 20% below its 52-week high, a bear market if we want to use that definition. These bad days in the Russell tended to be good signs for the S&P 500, though.
See this report for more detail.