Friday the 13th: Don't Fear the Market

On Wall Street, Friday the 13th superstitions go way back. It all started when a Boston stockbroker published a book called--you guessed it, Friday the Thirteenth--about an evil broker attempts to bring down the stock market on that day, according to Time's brief history of Friday the 13th. Some traders even saw it as a sign that during 1987--the year of Black Monday--three Fridays fell on the 13th of the month.

Jason Zweig looks at the hard numbers today in his Intelligent Investor column: it turns out that on average, the stock market actually performs better on Friday the 13th.He looked at stock-market returns going back to 1885, and found that the market rose by an average of 0.02 percent a day. Since 2000, he says, the market has gone down by about the same amount, but Friday the 13th surprisingly delivered an average of 0.28 percent. Says Zweig:

In the 1990s, Friday the 13th kicked butt, generating more than five times the return of the average day in the market. Researchers used to think there was nothing in these daily variations but random noise...but now some theorists are wondering whether the fear of Friday the 13th may actually raise average returns for the day, over time. Superstitious investors, afraid of “tempting fate," might sell stocks that day, creating purchase opportunities for more informed buyers and causing the market as a whole to go up. Scholars have documented that such factors as seasonal affective disorder, the shift to Daylight Savings Time and even how sunny it is outside can all influence short-term stock returns.

The takeaway: Don't fear the market today (any more than you normally would).