As Thanksgiving always falls on the fourth Thursday in November, the following Friday is observed by some as an unofficial holiday. Because many people are off work, shops drop prices – historically for one day only – to start the Christmas season.
UK shops have since caught on to this trend, bringing it across the pond over a decade ago. Between 2010 and 2013, Black Friday gradually built up momentum in the UK. In 2014, Black Friday became the peak pre-Christmas online sales day and many online retailers haven't looked back.