These are all the ways businesses are afraid of Friday the 13th

The fear of Friday the 13th (aka paraskavedekatriaphobia) goes way back before a hockey mask-wearing killer made it popular. Some of the earliest origins are in the Bible: Judas Iscariot was the 13th  dinner guest at the Last Supper and Jesus died on a Friday.  But even in pre-Biblical times a clerk accidentally omitted the number 13 from the Code of Hammurabi setting off thousands of years of head-scratching and superstition.

These ancient concerns over a number have lasted into modern times and the weird superstition is frequently incorporated into businesses. For instance, according to the Harvard Business Review:

Many buildings skip the 13th floor, especially hotels where they don’t want to spook guests
Airlines avoid having a 13th row
Airports frequently skip Gate 13
Software companies don’t release Edition 13.0 (Larry Ellison may have started that trend)
It’s estimated that the U.S. loses $700 to $800 million in business on these perceived “unlucky” days, according to a study by the Stress Management Center and Phobia Institute.

But while companies may be skittish about the number, one study found that Friday the 13th might actually be good for business.  Perhaps you’ve heard rumors that the stock market performs badly on this day? Turns out it’s not true. Marketwatch reports that Friday the 13th is traditionally a good day for the stock market, with stocks ticking upwards of 55.63%.

What’s more, a 2008 insurance study revealed that fewer traffic accidents occur on a Friday the 13th and reports of fire and theft both dropped. In short, when it comes Friday the 13th, as Public Enemy said: Don’t believe the hype.