Last month, two of your customers bought the exact same product at the exact same price. One paid from Paris. The other paid from Bangkok. You charged them identically. You delivered identically. But what landed in your account was not identical, and the difference had nothing to do with your margins, your pricing, or anything you control. It had to do with six digits printed on a piece of plastic in Thailand. Those six digits are called a BIN, a Bank Identification Number. They identify the bank that issued your customer's card and, crucially, the country where that bank operates....