A newcomer to business would imagine – and hope – that the global economy and leading lights of finance and enterprise ran on clear foundations of logic and clear-headed thinking, seldom at the mercy of random mood swings and allowing little room for superstition.
A few quick glances over a short period of time at the kneejerk jolts, spasms and occasional collapses stock markets are prone to suffer would furnish you with enough evidence that this is far from the case, of course.
As such, it will come as no surprise to many that the supposed 24 hours of naught but rotten luck that are Friday the 13th can have an impact on trading and the fortunes of retailers around the globe.
The marketplace is beholden to the buyer, so maybe it’s nothing more than the general public’s fears making them opt to do little of note until Saturday comes around. Maybe it's coincidence. Then again, maybe something altogether more sinister and supernatural is afoot.
One way to gauge it this time out is by taking a long at how London’s benchmark index has performed come closing bell.
The FTSE 100 is currently on a record-breaking winning streak and will hit a new high for a 12th consecutive day this evening. If it somehow falters, then, you can probably blame it on the 13th.
According to The Telegraph, on 70% of the Friday the 13ths over the past half decade, the FTSE has closed lower. Granted, a number of those years were in recessionary times...
Other markets have been ill-fated on the day, however. Back in October 1989, Friday the 13th became “Black Friday” when a failed acquisition of United Airlines’ parent company knocked 7% off the Dow Jones and 6% off the S&P 500, mere days after then-record highs. This came after the first Friday the 13th of the year saw IBM take a massive hit due to a virus wiping massive amounts of data.
More recently, the day saw China’s GDP growth fall to three-year low of 7.6% in July 2012, with the economic superpower only spluttering and slowing further in the years since.
On a smaller scale, it's also not a great time to be in business.
The Stress Management Centre and Phobia Institute in Asheville, North Carolina, which specialises in treating people with triskaidekaphobes (those afraid of the day), found that between $800m and $900m is lost in the US alone on the day.
Founder Donald Dossey blamed it primarily on the fact that "people will not fly or do business they would normally do". Big purchases and even medical treatments are delayed.
Business analyst Mike Randazzo told QuickBooks: "Friday the 13th is a killer for small companies. Year after year, small businesses see a noticeable dip in customer traffic and sales on this foreboding occasion. The fears underlying such behaviour may not be rational, but the economic impact is undeniable."
The number 13 in general can cause problems, particularly in the hotel trade, where rooms and whole floors can go from "12" to "14" without missing a beat.
Fortune favours the bold
Due to the laws of supply and demand, you can conversely look at Friday the 13th as a great opportunity for braver shoppers.
Househunters are unlikely to save thousands just for completing their purchase today, but less people will be vying for the property, which could mean the process is that bit easier. FindaProperty.com found that there were were 43% less transactions on Friday the 13th compared to other Fridays between 2007 and 2012.
Calendar dates aside, a survey by the website Zoopla has just revealed that one in three homeowners would be less likely to buy a house if it had the unlucky number on the front door. Some developers, again, skip the number when they're building new houses because of the stigma.
Gavan Ryan is Senior Negotiator with Savills Ireland:
"Whenever the number 13 arises people invariably do comment on it and go 'oh, number 13, unlucky for some!' But it is generally more lighthearted – when it comes down to it, people tend to just get on with it and buy the particular property."
If you're booking a flight, you could shave a few quid off it if you get it done today. According to AOL, flight booking website Kayak found that prices on Friday the 13th a couple of years ago were 22% less than usual.
Walking down the aisle? Wedding website hitched.co.uk analysed March 2015 and found that 48% fewer couples got married on Friday the 13th than Friday the 20th.
Your next opportunity comes in October...