Fourth quarters in recent years have been strong periods for the equity market, but I wanted to put some hard numbers behind my recollections. I went back all the way to 1990 and calculated the S&P 500's performance for each of the last sixteen fourth quarters. The results, shown below, were even stronger than I had remembered.

As you can see, fourteen of the last sixteen years have produced positive S&P 500 returns in Q4. The mean return for the period since 1990 has been 6.5%. The average gain in the positive years is 8.0%, while the average loss in the negative years is only 4.5%.

Does this mean investors should be 100% equities going into October? Surely some will do just that based on these statistics, but I am being more cautious. The market has had a very, very strong third quarter and I want to protect some of those gains.

Stocks simply feel overbought currently. With the average fourth quarter producing a 6.5% gain since 1990, I am going to have to take "the under" and say this year will be less impressive than average. On the bright side, I'll be thrilled if I'm wrong!