Private equity and other nondoctor investment in U.S. health care has grown significantly over the past decade thanks to investors who have been keen on getting into a large market with potentially high returns. As business opportunities abound for both licensed physicians, dentists and other licensed and nonlicensed entrepreneurs and investors in the ownership and operation of medical and dental practices, ambulatory care facilities, drug treatment facilities, diagnostic testing facilities and other types of health care facilities, doctors and business individuals and entities must ensure that the structure of their businesses comply with their state's corporate practice of medicine (CPOM) doctrine.