A long firm
is a trading company set up for fraudulent
purposes; the basic operation is to run the company as an apparently legitimate business, gradually extending the amount of cash advances from customers at the same time
as increasing the amount of credit
from suppliers; when the pot is large enough, the perpetrators decamp with customers' money and suppliers' goods. The procedure needs a certain amount of money to set up, often the proceeds from another crime or a previous long firm.
Long firm frauds have become significantly less common in recent years since it is no longer possible to operate for any length of time without leaving a significant paper trail. Online shops do, however, offer new possibilities.