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What’s a BIN?

  • February 17, 2026

Historically, a bank identification number (BIN) has been made up of the first six digits on a credit or debit card. Recently, some issuers have begun to use the first eight digits to identify a specific BIN within their portfolio. These numbers provide critical information that can be leveraged during the payment authorization and risk evaluation processes.

For example, cards issued by Visa begin with a “4”, while most MasterCard issued cards begin with a “5” (recently, MasterCard began issuing cards that begin with a “2”). While often overlooked, the BIN plays a foundational role in determining whether a transaction is approved, declined, or flagged for risk.

Banks often issue cards under more than one BIN, with some banks (e.g., Bank of America) using upwards of 200 different BINs to identify specific card portfolios. It’s important to note that authorization, fraud and other payment characteristics do vary significantly within a bank’s list of issuing BINs.

Why BINs Matter in Payment Authorization

The BIN is one of the first data points evaluated during the customer authorization process. It identifies which issuer should be contacted to verify cardholder information such as:

  • Whether the account is valid
  • If sufficient funds or credit are available
  • If the transaction aligns with the cardholder’s typical behavior

BIN data is especially important in card not present (CNP) transactions, where the risk of fraud is inherently higher. Leveraging BIN data helps transactions flow smoothly and can help protect both Merchants and consumers from fraudulent transactions.

What Information Can Be Identified Through a BIN?

BIN data enables Merchants and payment providers to assess transaction risk by identifying key characteristics of the card, including:

  • The card brand (Visa, MasterCard, Discover, American Express, etc.)
  • Issuing bank or financial institution
  • The card tier (Black, platinum, etc.)
  • Whether the card being used is a debit, credit or pre-paid card

Using BINs to Improve Authorization Rates

Understanding BIN data allows Merchants to optimize initial payment and decline recovery strategies based on card type, risk screening, and funding patterns. For example:

  • Prepaid cards may perform better when transactions are submitted at specific points in the month, depending on when funds are loaded.
  • Debit cards often see higher authorization rates at the beginning or middle of the month, when balances are more likely to be available.
  • Credit card portfolios can have higher levels of declines as the risk to the financial institution is great for credit cards than debit cards.

Because BIN performance varies by portfolio and business model, Merchants should continuously analyze BIN level data (e.g., decline response codes, approvals by day of the month, etc.) to determine what timing and strategies yield the best results.

BINs, Risk Profiles, and Dispute Exposure

Each BIN represents a distinct segment of customers, but not all BINs carry the same level of risk. Some BIN ranges are historically associated with higher dispute rates, increased fraud activity, and greater likelihood of chargebacks.

These percentages can negatively affect a Merchant’s ratios and potentially land them in the card brand dispute and fraud programs such as Visa’s VAMP program. Knowing the make-up of your portfolio can help a Merchant understand whether or not they need to work with third-party vendors to lower risk and identify these riskier customers before they could become a problem.

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