The Bank of South Australia, known commercially as BankSA, was originally the State Bank of South Australia. It was sold to and merged with Advance Bank due to a collapse and bailout by the Government in 1992. BankSA has 55 branches in metropolitan Adelaide, 66 in rural South Australia (totalling 121 overall in the state, more than any other bank in South Australia), four in the Northern Territory and one in Queensland.

As at 1 December 2008, St.George (and consequently the division of BankSA) became a subsidiary of Westpac Bank.