A New Number Series for Mastercard
Until recently, the 16-digit number of every Mastercard started with the number five. This is because the number five is part of the Mastercard bank identification number (BIN). The BIN is the first six digits of an account number and identifies the issuing institution for the account, ensuring each transaction is routed correctly. Previously, banks issuing Mastercards have used BINs ranging from 510000-559999.
As of January 2017, Mastercard now supports a new BIN range beginning with