What is a Bank Identification Number (BIN)? A Bank Identification Number (BIN) is the first six digits of a credit, debit, or prepaid card number. It is used to identify the financial institution that issued the card and helps to prevent fraudulent transactions. BINs are also known as Issuer Identification Numbers (IINs) because they identify the issuer of the card. Each financial institution that issues cards has a unique BIN or range of BINs assigned to it by the International Organization for Standardization (ISO). The remaining digits in the card number are unique to each individual card and are used for identification and security purposes. BINs are used by merchants and payment processors to validate and authorize transactions. They are also used by fraud detection systems to identify suspicious or fraudulent transactions. BINs can also provide valuable information for marketing and data analysis purposes, such as identifying the geographic location of cardholders and the types of cards they use.