Mainstream Group Holdings Ltd. engages in financial services business. The firm offers fund administration, custody, and superannuation services. It operates through the following geographical segments: Asia-Pacific, Americas, and Europe. The Asia-Pacific segment is also called as APAC and it includes Australia, Singapore, and Hong Kong. The Americas segment includes USA and the Cayman Island. The Europe segment includes Ireland, the Isle of Man, and Malta. The company was founded by Byram Johnston and Martin Smith in 2006 and is headquartered in Sydney, Australia.