Bank Identification Number (BIN)

A bank identification number (BIN) is used to uniquely identify each bank or financial institution within the card networks. BINs are used to identify both issuers and acquirers.

Since cards can be issued by entities other than a bank — American Express, for example — issuer identification number (IIN) is often a more accurate term.

How Are BINs Used?

Merchants most commonly use BINs to identify the bank that issued a given card. They use this information to submit authorization requests and ensure payment settlements are routed to the correct institution. Merchants might also analyze chargeback data by BIN to determine which institutions process the most chargebacks — here is an example.

Major Industry Identifier (MII)

The first 4-8 digits of a cardholder’s account number reveal the issuer’s BIN. The first digit is called the major industry identifier (MII) and describes the issuer’s industry. The MII also helps identify the card association the issuer is a member of.

MII Digit ValueIssuer CategoryCard Brand
0ISO/TC 68 and other industry assignmentsNone
2Airlines, financial, and other future industry assignmentsMIR, Mastercard
3Travel and entertainmentAmerican Express, Diners Club Carte Blanche, Diners Club International, JCB
4Banking and financialVisa
5Banking and financialMastercard, Diners Club US & Canada, Maestro, Dankort
6Merchandising, banking, and financialDiscover, China UnionPay, InterPayment, InstaPayment
7Petroleum and other future industry assignmentsNone
8Healthcare, telecommunications, and other future industry assignmentsNone
9Reserved for assignment by national standards organizationsN/A
More Industry Terms

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