Overly Strong Reactions Are Often Overreactions

If you left 10 minutes early on Wednesday you missed a lot. The S&P lost over 3% from 3:50 to 4pm and was down over 4% before bouncing in the last minute. I looked back over the last 25 years to find other times the market dropped 3% or more in the last 10 minutes of the day. This was the 1st. Lowering the requirement to 2% unveiled 3 instances. They are listed below along with the next day’s performance:

10/19/87 – S&P rose 5.23% the next day.
9/29/08 – S&P rose 5.27% the next day.
10/27/08 – S&P rose 10.79% the next day.

This is too small a sample size to use for analysis, but a nice illustration of a simple adage. An overly strong reaction is often an overreaction.