Bank State Branch

A Bank State Branch (often abbreviated and used in conversation as "BSB") is the name used in Australia and New Zealand for a bank code, which is a branch identifier. Both countries use an identifier consisting of a six digit numerical code that identifies an individual branch of an Australian and New Zealand financial institution. The BSB is normally used in association with the bank account number. (The structure of the BSB + account number does not permit for account numbers to be transferable between banks.) However, the New Zealand and Australian systems are only for use in domestic transactions and are incompatible with each other. For international transfers a SWIFT identifier is used in addition to the BSB identifier and a bank account number.

The use of the BSB identifier in association with bank account numbers was introduced in the early 1970s with the introduction of MICR on cheques to mechanise the process of data capture by the banks as well as for mechanical sorting and bundling of the physical cheques for forwarding to the payer bank branch for final cheque clearance. Since then the BSB code has been extended for use in electronic transactions, but is not used with financial card numbering.

In Australia, the Australian Payments Clearing Association (APCA) is the regulatory body of cheque clearances and of the BSB codes in Australia. The BSB code consists of six numerals, the first two or three of which is a bank identifier. APCA assigns the bank code to a financial institution and the financial institution allocates the other digits to its branches, in line with guidelines set by APCA. Some financial institution have more than one bank identifier, arising from mergers or consolidating by banks of their trading and savings banks operations. As of March 2012, almost 14,300 unique BSB code values were in use.