8 market superstitions: Should you be afraid?

Wall Street traders and investors have had a tumultuous August this year. And they're ready for a new month to begin. But the new month is September, which can be a difficult time of year. We hear things like: "The back to school trade is always down," and "Remember September always underperforms."

Is that a fact or is it just a market superstition?

Black cat eyes scary
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Fact. September is statistically the worst month of the trading year: The average percent change from 1928 to 2015 is down 1 percent.

Read MoreAnother stocks horror story for September?

So, as we get ready to face September, let's huddle around the fire pit and talk about some common Wall Street superstitions.

1) The witching hour: 2-3pm
When I was at the Galleon Group, we always closely watched the 2-3 p.m. trading hour. If the market sold off in that time, it usually meant that the market would close on a positive note. We would be buying stocks at 3 p.m. for a stronger close. There was no statistical evidence to support this — it worked until it didn't.

Should you be afraid? No.

2) New moon vs. full moon
Some people subscribe to the theory that a new moon is good for the market, whereas a full moon is very, very bad. There's no statistical evidence to support this theory and if there is – I couldn't find it. Just in case you want to test it out: Sept. 13th and the next full moon is Sept. 28th.

Should you be afraid? No.

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3) Sell on Rosh Hashanah and buy on Yom Kippur
The superstition, which is said over and over again on trading desks, works like this: The first day of the Jewish New Year is the time to sell some of your positions, and then you buy them back on Yom Kippur, the "Day of Atonement." This trade works more often than not. Rosh Hashanah coincides with the new moon this year — Sept. 13-15. Yom Kippur is Sept. 22-23.

Should you be afraid? Yes.

4) Buy on the cannons, sell on the trumpets
Going to war is considered good for the stock market. The reason being that there's a considerable amount of risk and uncertainty in the markets when countries go to war. This causes the market to sell off and create value in stocks. And by the time the trumpets announce the war is over – the fear is removed from the market.

Should you be afraid? Yes.

5) Big buildings = big selloffs
This makes sense — it indicates the top of the market. You only make plans to build the biggest building in the world when things are good. Things will always be good … or, so you think. And there are plenty of examples of this: The Chrysler and Empire State Buildings were completed right before the Great Depression, Sears Tower was completed in 1974 with a two-year low in the Dow; Malaysia's Petronas Towers were built in 1997, followed by the country's stock-market plunge; in 2008, Dubai owned bragging rights to the world's tallest building, which was followed by – yep, you guessed it — a stock-market crash.

Should you be afraid? Yes.

6) Health-care mafia code
In the world of health care, information is everything. Conferences are where a lot of information is concentrated. The theory is: Buy health-care stocks in front of JP Morgan's January health-care conference and then sell those same health-care stocks at the American Society of Clinical Oncology in May or June. It's like the opposite of hurricane season. But the sector doesn't always trade off of conferences.

Should you be afraid? No.

7) Super Bowl
The Super Bowl theory of stocks goes that the market will have a good year if a National Football Conference team wins the game and it will end the year lower if an American Football Conference team wins. From 1967 to 2003 it was correct 68 percent of the time. Though, that was followed by several years of AFC teams winning during an economic growth spurt. So, you're going to have to make that call.

Should you be afraid? No

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8) BOO! Trade

Just when you thought August was hair-raising and September was spine-tingling, here comes October, the statistically scariest month of the year! (And not just because of Halloween.) Some of the most devastating days in the market have happened in this month.

Should you be afraid? Yes.

So, while many on the street are happy to see August coming to a close; we've got a lot of superstitions and statistics to remind us that it's not yet time to get all bull'd up.

Commentary by Turney Duff, a former trader at the hedge fund Galleon Group. Duff chronicled the spectacular rise and fall of his career on Wall Street in the book, "The Buy Side," and is currently working on his second book, a Wall Street novel. He is also featured on the CNBC show, "The Filthy Rich Guide." Follow him on Twitter @turneyduff.