Last year I showed how the SPX has performed after the first day of the year was positive. Often you see a couple more days of upside followed by a selloff. In fact, there has been quite a streak of January dips after strong first days. Below are the last 10 instances going back to 1988, and their 13-day returns.

Most instances showed a decent amount of runup prior to the market rolling over. In fact the last five instances, starting in 2002 and ending in 2010, all saw the market rise 1%-3% before the move down ensued.