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It was one of those perfect English autumnal days which occur more frequently in memory than in life.

~P.D. James

Last September was a doozy. The feds swept in and seized Fannie Mae and Freddie Mac, while the market didn’t so much swoon as do a full-blown pancake on a hot cement sidewalk.

But, according to Wall Street historians, September and October are always pretty bad for making money in the market. Of course, the Great Depression kicked off in October. But that’s just the start of autumn’s financial malaise.

• Black Monday hit on Oct. 19, 1987
• The panics that made up the Great Depression–Black Thursday, Friday, Monday and Tuesday–all occurred in on October of 1929.
• There were panics in September 1869 and September 1873, Then there was the sell-off following the Sept. 11 attacks.

It’s a pretty impressive line up of evidence, right? But does that make it a curse?

Louis Navellier says maybe, but  the curse might not be too bad.

Here’s the bad news:

Since 1926, investors have lost nearly 1% on average during September, according to market data tracked by finance professor Kenneth French at Dartmouth’s Tuck School of Business. It’s the only month with a negative return. For each of the other 11 months, investors gained nearly 1%.

Georgia Tech doctoral student Hyung-Suk Choi examined data for 18 developed stock markets overseas, going back 200 years: 15 of those markets (83%) were net-negative in September.

But, if you take the gianormously bad days out of the equation, Navellier says the September-October curse (now forever referred to here as “Cursember”), you’ll find the sixty days of autumn are only a moderate curse.

Again, taken from Navellier’s blog:

If you look at the monthly median rather than the mean, the median September (since 1926) lost just 0.07%, which is darn close to breaking even. But alas, the median among the other 11 months was a stellar +1.37%!

So, the curse appears to be another investing bias.

Investor biases taint the way traders and investors see the market and cause trading mistakes. It’s also one of the benefits of using Automated Trading systems to run at least a part of your portfolio.

Especially during these autumn days of discontent.

Related posts:

1. Should Commodities Investors Worry About Global… Cooling
2. Small Investors Can Fight Back Against High-Speed Investing
3. Weekly Wisdom: Autumn Begins, Financial Wisdom Continues
4. Lie: Investors Can Only Make Money When The Economy Is Good
5. Seven Emotions Investors Can Do Without

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