On a credit card, the bank identification number consists of the first four to six digits on the card. This indicates the issuing institution, and it is vital for verification of transactions to that issuer. These numbers also appear on debit cards, charge cards and electronic benefit cards.
Even though the word "bank" appears in the acronym, other institutions such as American Express use BINs also. The term identification number, or IN, is coming more into parlance as more non-bank issuers are joining the network to take advantage of the identity verification. The prefix system also helps to find possible identity theft or other security breaches.