During the 1990s, the delivery of health care services was increasingly influenced by the demands of investors and investor-owned firms. A growing number of hospitals, health maintenance organizations (HMOs), nursing homes, home care services, and hospices became for-profit companies, publicly traded on stock exchanges. Companies formed to fill particular niches, such as those that manage physicians' practices and utilization-review firms, became Wall Street favorites. The buying and selling of health-industry assets, as fungible commodities, intensified. In the meantime, traditional for-profit entities such as medical-device and drug companies continued to thrive. In the early part of the decade, the performance of . . .