What Is Issuer Identification Number? Definition, Payment Flow, and Examples
Issuer Identification Number (IIN) is the leading portion of a PAN assigned to identify an issuer's card-number range under applicable standards. This guide focuses on IIN's real role, boundaries, and common points of confusion.
Key points
- Definition: Issuer Identification Number (IIN) is the leading portion of a PAN assigned to identify an issuer's card-number range under applicable standards.
- Flow position: The PAN identifies a card-account relationship in payment processing, while an IIN or BIN is the leading range used for issuer identification and routing.
- Do not confuse: IIN / Bank Identification Number
How it fits into the payment flow
For IIN, the relevant process is as follows: The PAN identifies a card-account relationship in payment processing, while an IIN or BIN is the leading range used for issuer identification and routing. Six- and eight-digit IIN allocations exist, so systems should not permanently assume a six-digit BIN.
A practical review of IIN should account for this: troubleshooting should retain only the identifiers that are necessary. A merchant ID identifies an acceptance-side merchant, not the cardholder account, and it is not a substitute for a transaction identifier.
Practical example
A processing platform uses the IIN to identify the issuing range and combines it with complete transaction data for routing. The IIN identifies an allocation, not the legitimacy of the person submitting it.
How it differs from related terms
| Term | Definition |
|---|---|
| Issuer Identification Number | is the leading portion of a PAN assigned to identify an issuer's card-number range under applicable standards |
| Bank Identification Number | is the traditional industry name for the leading PAN digits that identify an issuing range; IIN is the more formal modern term |
| Primary Account Number | is the principal card number carried in card credentials and used to identify the issuer range and the particular card-account relationship |
IIN focuses on the fact that it is the leading portion of a PAN assigned to identify an issuer's card-number range under applicable standards. Bank Identification Number, by contrast, is the traditional industry name for the leading PAN digits that identify an issuing range; IIN is the more formal modern term. They can appear in one transaction while answering different questions.
Use cases and limits
A key limit of IIN is the following: A full PAN is protected cardholder data. Display masking, log redaction, and stored-data truncation are different controls; seeing only the last four digits on screen does not prove the backend lacks a full PAN.
Frequently asked questions
These answers address two common search questions about IIN.
Is it the same as Bank Identification Number?
No. Issuer Identification Number (IIN) is the leading portion of a PAN assigned to identify an issuer's card-number range under applicable standards. Bank Identification Number (BIN) is the traditional industry name for the leading PAN digits that identify an issuing range; IIN is the more formal modern term. Compare the object, processing stage, and responsible party.
Are BIN and IIN always two different numbers?
For IIN, they are commonly used for the issuer-identifying leading range of a PAN. Length and terminology should follow the network, ISO allocation, and system documentation in use.
These primary sources support the definition and process for IIN. Current product, network, and local rules still control a real transaction.