Should investors fear October, a historic ‘jinx month’ for stocks?

The month of September hasn’t lived up to its reputation for historical weakness in the U.S. stock market, which could provide some comfort to superstitious investors looking ahead to October, a month that is notable for some historic crashes and other turmoil.

According to the Stock Trader’s Almanac, October is known as “the jinx month” due to the number of major selloffs that have occurred in the past over the month. There were “crashes in 1929 and 1987,” the Almanac read, along with “the 554-point drop on October 27, 1997, back-to-back massacres in 1978 and 1979, Friday the 13th in 1989, and the meltdown in 2008.” Such rough years have made October a relatively weaker month for the major averages, even as it is typically a positive one, especially in midterm-election years.

Historically speaking, the Dow Jones Industrial Average DJIA, -0.40% rises an average of 0.6% over the month, a move that makes October the seventh-best of the year. Over the past 67 years, October has been positive for the blue-chip average 40 times and negative in 27 times. The S&P 500 SPX, -0.33% typically rises 0.9% over the month, which is also good enough for seventh place, based on historical averages. The benchmark index has the same ratio of positive Octobers to negative ones as the Dow. For the Nasdaq Composite Index COMP, -0.21% October stands as the eighth-best month of the year, based on data that goes back 46 years. It has historically risen 0.7% over the month, and October has been positive for the Nasdaq in 25 of the past 46 years.