The three biggest crashes in US stock markets occurred in October 1907, October 1929, and October 1987. And there have been other significant October falls over the past 100 years - most notably in 1989 and 1997 - leading some to speculate that there is an “October Effect”.

Common sense suggests that this is nothing more than market folklore. After all, there are only 12 months in a year and there have been plenty of other months, notably March, that have seen big market declines, such as when the Dot Com bubble burst in 2000 and the Covid-related meltdown in 2020.

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