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October and Crashes: Why This Month Has a Bad Reputation — and What to Do About It
Key takeaways
- October 1929 and 1987 cemented its reputation, but an average October is like any other month.
- Stock market seasonality is a weak signal — not worth building a strategy around.
- If markets fall, the right response is to do nothing or to buy more.
- Discipline and a plan are worth more than the ability to read market sentiment.
- An investor with a plan sleeps soundly even in October.
October has a reputation in investment folklore as a dangerous month — owing to two specific dates: the 1929 crash and Black Monday in 1987. Statistics, however, say that the average October is no worse than the average February.
Where the reputation came from
The "October effect" arose after two extreme events: the Great Depression began on 24 October 1929, and Black Monday on 19 October 1987 brought the largest single-day fall in Dow Jones history (over -22%). These events etched themselves into the memory of generations of investors. But selective recall of crashes doesn't mean October is systematically worse.
What the statistics say
Looking at average S&P 500 monthly returns over the past several decades, October comes out as an average or slightly positive month. Seasonal effects do exist — such as "Sell in May" or the "Santa Rally" — but they are weak and unpredictable. Trading based on the month of the year is a very bad idea. More on the principles of index investing in what is a stock index.
What to do (nothing — stick to the plan)
The right response to October, to newspaper headlines about a correction, or to an actual market fall is the same:
- Don't sell out of fear — selling at a decline locks in a loss and removes you from the recovery.
- Buy more if you have spare cash — lower prices are an opportunity for long-term investors.
- Continue regular DCA — DCA (cost averaging) automatically buys more at lower prices.
Why markets grow over the long term despite crises is covered in detail in this article. A plan and discipline are better protection than fear of any particular month.
FAQ
Is October really dangerous for the stock market?
Statistically no more than any other month. October's reputation comes from the Great Depression in 1929 and Black Monday in 1987 — two extreme events that etched themselves into memory. The average October is positive.
Does it make sense to sell in October and wait to see how things develop?
No. Timing the market doesn't work — the biggest gains arrive randomly and without warning. Those who sell out of fear and wait for the "right" moment to return usually miss it.
What is the best strategy for volatile months?
Stick to the plan. If you invest regularly and hold a diversified portfolio suited to your time horizon, a volatile month is just noise on a long journey. Buying the dip is a bonus, not an obligation.