BIN 521015 — Lookup & Card Details

BIN 521015 is on the Mastercard network.

A Bank Identification Number (BIN, or Issuer Identification Number / IIN) is the first 6 to 8 digits of any payment card. It tells the payment network which institution issued the card, what kind of card it is, and where it was issued. The card runs on the Mastercard network.

Mastercard is a global network whose BINs fall in the 51–55 and 2221–2720 ranges, accepted at merchants worldwide.

In practice this prefix is what a checkout sees first — risk engines score it, gateways route on it, and merchants use it to decide whether to accept the card class at all. BIN 521015 is institutional data under the ISO/IEC 7812 standard — looking it up reveals the issuing program, nothing about any cardholder.