Black Friday sale

Initially, the expression Black Friday had nothing to do with sales. On September 24, 1869, the gold market fell, and the day of the week was Friday. The expression was later used to refer to traffic jams in Philadelphia. In the 60s of the last century, in the period after Thanksgiving and before Christmas, that is, on Friday, attempts were made to rename Black Friday to Big Friday. But this time was the most profitable for store owners, as a result of which both huge discounts and the expression Big Friday did not take root, but Black Friday and discounts remained.
Another version is that at that time in stores, income was recorded in the ledgers in black ink, and expenses were recorded in red. The day of the sale, which was held on the Friday after Thanksgiving, was a big profit, hence the name.