A perspective on the corporate transformation of health care.

The ever-increasing ownership of health service providers, suppliers, and insurers by investor-owned enterprises presents an unforeseen complexity and diversity to health care delivery. This article reviews the history of the for-profit invasion of the health sector, linking corporate purchaser directions to the now dominant mode of delivery in managed care. These dynamics require unceasing reassessment while the United States embarks upon implementation of national health care reform.