This article covers what a bank identification number is, how its digit structure works, what a BIN reveals about a payment card, how it functions during a transaction, and why it matters for fraud prevention. It also covers the 2022 expansion to eight digits and the rise of BIN sponsorship in fintech.
Every time you tap your card at a checkout or enter your details online, a quiet piece of logic runs in the background, verifying who issued your card before a single penny moves. That logic starts with a bank identification number. Whether you are a cardholder, a merchant, or a business exploring card issuance, understanding what a BIN is and how it works gives you a clearer picture of how modern payments actually function.
What is a Bank Identification Number?
A Bank Identification Number (BIN), also called an Issuer Identification Number (IIN), is the first six to eight digits of the Primary Account Number (PAN) printed on a payment card. It identifies the financial institution that issued the card. Every credit, debit, prepaid, and gift card carries one, and the entire payment authorisation chain depends on it.
The term “IIN” is technically more precise: as fintechs and e-money institutions now issue cards too, “bank” has become something of a misnomer. In practice, both terms are used interchangeably across the industry, though you will see IIN more often in ISO documentation.
Q&A: Is a BIN the same as an IIN?
Yes. The two terms describe the same thing. “IIN” is the more accurate label under ISO/IEC 7812 because non-bank entities now issue cards, but “BIN” remains the dominant term in day-to-day usage.
How is a BIN structured?
BINs follow ISO/IEC 7812, the international standard for payment card numbering. The first digit of a BIN is the Major Industry Identifier (MII), which signals the issuing institution’s industry category. The remaining digits narrow identification down to the specific institution.
| Digit(s) | Name | What it identifies |
| 1 | Major Industry Identifier (MII) | Industry category of the issuer |
| 2-6 or 2-8 | Issuer identification | The specific bank or institution |
| Remaining digits | Account number | Unique to the individual cardholder |
| Final digit | Check digit | Validates the PAN via the Luhn algorithm |
The MII also signals the card network. Visa cards always start with 4; Mastercard cards start with 2 or 5; American Express with 3; Discover with 6. Glancing at the first digit of any card number tells you the network immediately, which is why a payment form can identify your card network before you finish typing.
Why did BINs expand from six to eight digits?
In response to a sharp increase in the number of card issuers, ISO announced an expected shortage of novel combinations for IINs and revised its official guidance under ISO/IEC 7812-1 to call for an expansion of the issuing BIN from six to eight digits. As of April 2022, Visa and Mastercard now require that all acquirers and processors in their networks accommodate eight-digit codes, and all new BINs assigned by either network feature eight digits.
The card volume driving that shortage is substantial. At year-end 2024, there were 27.76 billion payment cards in circulation worldwide, and that figure is projected to reach 31.13 billion by December 2029. Six-digit BINs could not keep pace with that scale of issuance.
The expansion did not change card numbers themselves, as PANs remained the same total length. Only the portion classified as the BIN grew. Card issuers are not required to use new eight-digit BINs if they still have a usable range of six-digit BINs, so both lengths continue to be supported across the industry.
Q&A: How many digits is a BIN in 2025?
Most newly issued cards carry an eight-digit BIN. Visa stopped assigning six-digit BINs after April 2022. Mastercard adopted the same standard but has not formally discontinued its six-digit BINs, so both lengths remain active across the global card base.
What does a BIN reveal about a card?
Quite a lot, and none of it relates to the individual cardholder. From the BIN alone, a payment processor can determine the card network (Visa, Mastercard, Amex, Discover, UnionPay), the specific issuing institution, the card type (credit, debit, prepaid, or gift), the card level (standard, gold, platinum, corporate, or business), and the issuing country.
This is why a merchant’s payment system can display Visa Platinum or Mastercard Business the moment you enter your card number, before authorisation even begins.
Q&A: Can a BIN reveal my personal account details?
No. A BIN identifies the issuer and the card category, not the individual cardholder. Your personal account number, name, and billing address sit in the digits beyond the BIN and are protected separately under PCI DSS.
How does a BIN work during a payment transaction?
The process is faster than it reads. When a payment is initiated at a terminal, online, or via a digital wallet, the merchant’s payment system extracts the BIN and passes it to the payment processor. The processor uses the BIN to route the authorisation request to the correct issuing bank. The bank checks the available balance, fraud flags, and card status, then returns an approval or decline. The whole exchange completes in under two seconds.
For merchants, accurate BIN data has direct commercial consequences. Misrouted transactions, failed network lookups, or outdated BIN tables can cause legitimate payments to decline, frustrating customers and costing revenue. That practical reality is one reason the 2022 migration to eight-digit BINs required significant infrastructure work across acquiring banks, processors, and merchants alike.
How do BINs help prevent card fraud?
BIN data is one of the first signals a fraud detection system checks. Cross-referencing the BIN against a transaction’s other details can surface several warning signs:
- Geolocation mismatch – a card issued in Germany used moments later in a transaction flagged as originating from outside Europe.
- Card type anomaly – a prepaid card presented in a context where corporate cards are the norm, or vice versa.
- Lost and stolen card check – the BIN routes the authorisation to the issuing bank, which checks the card against its own fraud and block lists in real time.
- Address Verification Service (AVS) – the issuing bank, identified via BIN, checks whether the billing address provided matches its records.
The scale of what is at stake makes these checks critical. Payment card fraud losses worldwide came to $33.41 billion in 2024, according to the Nilson Report, tied to global card volume of $51.920 trillion.
There is also a consumer-facing scam worth knowing. BIN fraud works like this: a fraudster calls a cardholder, recites their BIN to appear credible, then asks for the remaining card digits. The BIN is not sensitive data on its own; the full combination is. Never confirm complete card details to an inbound caller, regardless of what they already appear to know.
What is BIN sponsorship, and why does it matter for fintechs?
For most of the card industry’s history, obtaining a BIN meant applying directly to Visa or Mastercard, a process requiring a banking licence, lengthy regulatory scrutiny, and significant capital. That barrier defined which businesses could issue cards.
BIN sponsorship changes the equation. A licensed principal member of a card scheme, a regulated institution that already holds its own BIN ranges, can sponsor access to those BINs for third-party businesses. The sponsor handles the scheme relationship, compliance, and settlement. The client business handles the product, the brand, and the customer experience.
This model underpins much of the neobank and embedded-finance sector. When you receive a card from a personal finance app or a corporate expense tool, the BIN on that card often points to the sponsor institution in the background, not the brand on the front.
Issue your own cards with Wallester
Wallester is a Visa payment card issuer with BIN sponsorship that manages consumer and business card programmes. As the BIN sponsor and issuer, Wallester handles the regulatory side of the equation, including settlement, licensing, and scheme compliance, so businesses can issue physical and virtual Visa cards under their own brand.
As a certified Visa partner with individually assigned BINs, Wallester lets corporate clients sponsor those BINs without going through the direct application process. A dedicated BIN range is configured for your programme, and the launch timeframe generally ranges from four to eight weeks, a fraction of the time a direct scheme membership would require.
Wallester has been ranked the fastest-growing fintech in Europe in the Financial Times FT1000: Europe’s Fastest Growing Companies 2026, taking the number one position in the Fintech, Financial Services and Insurance category. Whether you are a bank, a marketplace, a lender, or a SaaS platform looking to add financial features, Wallester’s white-label infrastructure covers the BIN, the processing, the compliance, and the support in one place.
