An individual practice association (IPA) is a corporation or a partnership composed of physicians which contracts with health maintenance organizations (HMOs) to provide medical services to HMO subscribers. Since physicians typically practice independently, any agreement or arrangement among them may be perceived as an agreement of competitors. Hence, IPAs run the risk of challenge under the antitrust laws for activities such as price-fixing and the exclusion of physicians from membership.
Prior to the recent Supreme Court decision in Arizona v. Maricopa County Medical Society, it appeared that courts were willing to consider a variety of factors that distinguished antitrust cases concerning health care providers from antitrust cases in the commercial marketplace, and to find that conduct by providers did not constitute antitrust offenses. Indeed, an earlier article appearing in Law, Medicine & Health Care analyzed the lower court's decision in Maricopa and discussed the development of this trend.