The Finance Sector Union was founded in July 1991 when the two main unions in the banking and insurance industries - the Australian Bank Employees' Union (ABEU) and the Australian Insurance Employee's Union (AIEU) voted to amalgamate and create the FSU.
Three smaller unions also linked up: the AMP Society Staff Association, Trustee Companies Officers' Association and Wool Brokers' Staff Association. In March 1994, the FSU was further strengthened when the Commonwealth Bank Officers' Selection (CBOS) joined with the FSU.