Australia's private health insurance funds have been prominent participants in the nation's health system for 60 years. Yet there is relatively little public awareness of the distinctive origins of the health funds, the uncharacteristic organisational nature of these commercial enterprises and the peculiarly regulated nature of their industry. The conventional corporate responsibility to shareholders was, until recently, completely irrelevant, and remains marginal to the sector. However, their purported answerability to contributors, styled as 'members', was always doubtful for most health funds. After a long period of remarkable stability in the sector, despite significant shifts in health funding policy, recent years have brought notable changes, with mergers, acquisitions and exits from the industry. The research is based on the detailed study of the private health funds, covering their history, organisational character and industry structure. It argues that the funds have always been divorced from the disciplines of the competitive market and generally have operated complacently within a system of comprehensive regulation and generous subsidy. The prospect of the private health funds enjoying an expanded role under a form of 'social insurance', as suggested by the National Health and Hospitals Reform Commission, is not supported.