October Monthly Behavior in the S&P 500
October 1, 2009

Now that October has arrived, here's its entry in our monthly behavior series!

When we measure monthly performance as a percent gain or loss from the previous monthly close, October has been a relatively weak performer in the S&P 500 since 1928, which is far back as I have S&P monthly close data.*

Each bar in the chart shows the October close change from the September close. Since 1928 October closes have an average gain of 0.27%, but the month has also been home to a few bear bottoms. Of the eight previous bear markets since 1950, four of them hit their low in October (1957, 1966, 1974 and 2002).

For previous posts on seasonality, see August and September and also my "Behavior of the Months" series: Part 1, Part 2 and Part 3. For an interesting international website with more detail on seasonality and the driving forces behind it, see seasonalcharts.com.

*Monthly averages of daily close data, used extensively elsewhere at dshort.com is available back to 1871 at Robert Shiller's Yale website. See Part 2 and Part 3 for more on monthly behavior using this metric.