įor American Express, they issue their credit cards themselves. The structure of the 16 digit PAN (Primary Account Number) includes: system identifier, issuer/bank identifier, bank number, account number, a check digit. Visa and MasterCard do not issue credit cards instead, they use banks (financial institutions) to issue the cards. “Visa and MasterCard always have 16 digits whereas American Express has 15 digits. That is because IINs are used by companies other than Banks too. The first 6 or 8 digits of a payment card number (credit cards, debit cards, etc.) are known as the Issuer Identification Numbers (IIN), previously known as Bank Identification Number (BIN). The card number on financial cards are usually 16 or 19 digit long. Card Number is also known as “Primary Account Number (PAN)”.