Over the last five years, the FTSE 100 has closed lower on seven of the 10 Friday 13ths.
It could be a coincidence - or is there something else at play?
On Friday 13th July 2012, China's GDP growth dropped to a three-year low of 7.6 per cent, marking a new stage for the country's economic slowdown.
A few months earlier, the Italian cruiseliner Costa Concordia ran aground on the same doomed date in January, killing 32 people and wiping more than a fifth off its owner Carnival's share price.
On Friday 13th October 1989, a day that is now often referred to as Black Friday, the failed US$6.75 billion (NZ$9.44b) buyout deal for United Airlines' parent company sent global markets plunging, knocking 7 per cent and 6 per cent respectively off the Dow Jones Industrial Average and the S&P 500, which had reached record highs just days earlier.
In January of the same year, IBM took a hit as the Jerusalem virus wiped irretrievable data off computers across the UK on Friday 13th.
Superstitious beliefs run so high in the UK that some people refuse to fly on Friday 13th, stay in hotel rooms bearing the unlucky digits or buy houses that bear the number 13.
In fact, the Stress Management Center and Phobia Institute in North Carolina estimates that businesses lose up to US$900m in sales and productivity when the 13th of the month falls on a Friday as customers refrain from activities such as flying and anxious employees stay home from work.
The phenomenon even has a name: paraskavedekatriaphobia is the fear of Friday 13th, while triskaidekaphobics are scared of the number 13 more generally.
More than a quarter of Britons admit that they consider Friday 13th to be unlucky, according to a survey of 500 adults conducted by the conference call provider Powwownow.
One in 10 people avoid travelling by train on Friday 13th, 11 per cent refuse to stay in hotel room number 13 and 16 per cent of people won't take flights on this inauspicious day, the survey found.
The flight booking website Kayak found that June 13th - a Friday - was the cheapest day to fly in 2014, with travellers' superstitions about the date knocking 22 per cent of the average price that month.
A staggering 37 per cent of respondents said they wouldn't buy a house that is number 13.
A report published in the British Medical Journal, Is Friday the 13th Bad For Your Health, found that the number of road accidents in a specific region of the UK were 52 per cent higher on Friday 13ths than on the previous Friday.
The Powwownow survey found that women tend to be more superstitious than men, with a third considering Friday 13th to be unlucky, compared to a fifth of their male counterparts. Half of female respondents admitted to having superstitions, more than twice the number of male respondents.
Younger people feel the same way: 29 per cent of people between the age of 18 and 24 prefer not to fly on Friday 13th, almost twice the average number, and 25 per cent of this age group reported having a bad experience on this date, compared to just 12 per cent overall.
Geographical location and culture plays a large part in the development of these superstitions, particularly as the vast majority of respondents - even those who feared the date - admitted that they did not know why Friday 13th was considered unlucky.
Half of Northern Irish respondents said they believe Friday 13th is unlucky, twice as high as the average response, with 64 per cent admitting they have superstitions, compared to 38 per cent overall.
Scots, on the other hand, are a more practical bunch: just 13 per cent consider Friday 13th to be unlucky, with not one person saying they would avoid staying in hotel room number 13.