Monday's (2/5/18) drop of 1,175 points for the Dow was the largest single-day point loss ever. But convert it to a percentage and that day's -4.60% decline doesn't even register in the top 100 largest single-day losses. And as yesterday (2/6/18) shows, volatility moves markets in both directions.
Indices are unmanaged and cannot be invested into directly. Past performance is not indicative of future results.