September, historically, is the worst month of the year for the stock market. It appears the fundamental reason is that earnings reports for the first and second quarters don’t really tell the full story of how corporations are doing for the year. The third-quarter earnings are really important since they give strong guidance on how corporations will do for the calendar year. Most significant reporting doesn’t begin until the third week in October. The anticipation of what these reports might look like gets the markets a little spooked in September.