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Issuer Identification Numbers (IIN)


The Issuer Identification Numbers (IIN) is a global system of identification numbers for card issuers that forms the first six digits of a payment card number. These are used in credit, debit, and other cards to identify the issuing institution which the card was issued from. This identification assists with transactions and fraud prevention within the global financial industry.


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  1. Issuer Identification Numbers (IIN) are the first six digits of a credit card number. They help in identifying the institution that issued the card to the card holder, ensuring swift and accurate transactions.
  2. IINs are regulated by the International Organization for Standardization (ISO) and the American National Standards Institute (ANSI). This assures a standard format which contributes to global financial security and stability.
  3. Each IIN is unique to the issuing institution and provides significant information including the card brand (e.g., Visa, MasterCard), card level (e.g., Gold, Platinum), and the card’s geographical issuing region.

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Issuer Identification Numbers (IIN), previously known as Bank Identification Numbers (BIN), are vital in the finance industry, primarily in enhancing the security and efficiency of electronic transactions. These are the first six digits of a card number on payment cards such as credit and debit cards, and they serve to identify the institution that issued the card to the cardholder. IINs are essential for facilitating and streamlining card transactions as they enable businesses, merchants, and payment processors to immediately authenticate and identify the issuing bank, card type, and card level. This immediate identification helps prevent fraudulent transactions, reducing financial risks for all parties involved. Consequently, IINs contribute significantly to ensuring the reliability, safety, and efficiency of electronic payment systems worldwide.


Issuer Identification Numbers, or IINs, serve a significant purpose in the financial and business world by identifying the specific institution that issued a particular credit, debit, or prepaid card to a consumer. Through this identification system, card transactions can be accurately directed to the correct banking institution.IINs are essential for facilitating the smooth and secure processing of millions of electronic transactions daily. They enable the backend communication between different financial institutions, card networks, and payment processors. They help in verifying transactions, ensuring that the funds are appropriately debited or credited, and contributing to fraud prevention efforts by confirming the legitimacy of the issuing institution. When a cardholder makes a purchase, the IIN system is used to route the transaction to the correct place, thus making the payment process efficient and reliable.


1. Credit Cards: One of the most common examples of an Issuer Identification Number (IIN) is the first six digits of a credit card number. It identifies the institution that issued the card. For instance, Visa cards typically start with the digits 4, MasterCard starts with 5, etc. 2. Debit Cards: Similar to credit cards, debit cards also have IINs. These numbers not only help to identify the issuing institution but also help to streamline electronic transactions, making them faster and more accurate.3. Mobile Payment Systems: Companies like Apple Pay or Google Wallet also use IINs for issuing virtual cards to their users. These numbers help the platforms to identify the financial institution responsible for the card account that is linked to the mobile payment system.

Frequently Asked Questions(FAQ)

What is Issuer Identification Number (IIN)?

The Issuer Identification Number (IIN), also known as Bank Identification Number (BIN), is the first six digits of a credit card number. These numbers are unique and are used to identify the issuing institution of the card.

What is the purpose of the Issuer Identification Number (IIN)?

The main purpose of the IIN is to identify the institution that issued the card. It helps in the validation process when the card is used for transactions and assists in fraud prevention.

How is an IIN formatted?

An IIN is a six-digit number. The first digit is the Major Industry Identifier (MII), representing the card’s category (banks, travel, entertainment, etc.). The next one to five digits represent the issuer identifier, identifying the institution that issued the card.

Can multiple cards have the same IIN?

Yes. Various cards from the same issuing institution can have the same IIN, as the IIN identifies the issuer, not the individual card.

Can one issuer have multiple IINs?

Yes, larger institutions or banks may have several IINs. This is because an issuer might have different IINs for different card types (e.g. debit, credit, prepaid) or partnerships with various businesses or organizations.

Is there a public directory of IINs?

The American Bankers Association (ABA) used to maintain a public directory of IINs. Today, it has been transferred to the responsibility of the International Organization for Standardization (ISO) and is not publicly available.

How does an IIN aid in fraud prevention?

When a card is used, the IIN can be quickly validated against the issuer, ensuring the card is genuine. If it doesn’t match the issuing institution’s records, it can be a potential sign of fraudulent activity.

Can an IIN be changed?

Normally, IINs are static and do not change once assigned to an issuer. However, in the case of bank mergers and acquisitions, new IINs may be adopted.

Are IINs used in all countries?

Yes, IINs are used globally because they conform to the ISO/IEC 7812 international standard.

: How are new IINs assigned?

New IINs are assigned by International Organization for Standardization (ISO). The issuing institution has to apply for an IIN from ISO.

Related Finance Terms

  • Bank Identification Number (BIN): This is the first six numbers of a card number (credit, debit, etc.) which are uniquely assigned to every bank or financial institution. It is often used interchangeably with IIN.
  • Credit Card Issuer: This refers to the bank or financial institution that provides (issues) the credit card associated with the IIN.
  • ISO/IEC 7812: This is the international standard that defines the structure of the IIN and PAN (Personal Account Number).
  • Card Brand: A payment network like Visa, Mastercard, Discover or American Express to which the IIN belongs.
  • Card Verification Code (CVC): Also known as CVV, this security feature on credit or debit cards is used to prevent fraudulent transactions. It is separate from the IIN but related in the context of card security.

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