The Best and Worst Months for the S&P 500 Index (1926 – 2006)

September 5, 2007

From 1926 – 2006, only ONE month has averaged a negative return for the S&P 500 Index*. Can you guess what month that was?


That’s right, only September has averaged a negative monthly return every year since 1926. Another way to look at it: had you invested your money during the month of September every year since 1926, you would have had an average monthly return of -.76%!

The best month?

The best month for the S&P 500 Index historically has been July with an average monthly return of 1.86%.

Here’s a complete list ranked by month:

The Best and Worst Months for the S&P 500 Index

Now here’s a look at each month:

The Best and Worst Months for the S&P 500 Index

It’s interesting to note that although the month of December had the greatest number of up months, it’s average performance still lagged the month July.

Finally, for those who are interested, here’s a look at the year in which the best and worst months occured:

The Best and Worst Months for the S&P 500 Index

Notice that most of them occured in the 1930s – evidence of just how volatile the 1930s were (that and it was also probably due to the fact that the index traded for a lot less than it does now, which made each point worth a greater percentage).

One last bit of trivia for you:

From 1926 – 2006, there were 972 months. Of those 972 months, 605 (62%) of them were up months and 367 (38%) were down months.

*From 1926- March 3, 1957, the S&P consisted of 90 stocks. It was expanded to 500 stocks on March 4, 1957.

Source: Appendix B of The Only Three Questions That Count (Affiliate Link) by Ken Fisher and this spreadsheet download from I entered the data and performed the calculations on my own.

10 responses to The Best and Worst Months for the S&P 500 Index (1926 – 2006)

  1. Interesting information. October through December has a very strong pattern of being up months. It is interesting that although September has an overall negative return on average, there is still one more up month than down. September has obviously been a month where there have been some severe selloffs which serve to skew the average to some degree.

  2. What I read from this information is that it is really worthless to try to time the market. Over this long period of time, there have been more up months than down (even in September). In the end over the long term an investor will stay ahead if they follow a consistent approach that balances risk.


  3. Going back to 1926 skews the data. The investment world from 1926 through 1940 was very different from the post war investment world. 18 of the 24 (3/4 of the total) best and worst months were from 1926 to 1940. These years were more volatile than later years. If you stick with the later years after WW II, then the six months from November thru April do much better than the months from May thru October. And, there are more Septembers with a loss than a gain, the only month for which this is true.

    • Thanks for your comment, Nick. I’ve done stuff in the past where I didn’t go all the way back to the beginning of the data and people basically accused me of data mining. I have done posts like this in the past and I think I mentioned the clustering of the data in the 20s and 30s. I guess I should not that in this post too.

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