Around 1,750 doctors in Maricopa County, Arizona, joined the Maricopa Foundation for Medical Care (the Foundation) (defendant). The Foundation established a set of maximum fees that member-doctors could accept as payment for medical services that were provided to patients covered by medical-insurance plans approved by the Foundation. The individual member-doctors had no financial interest in the operation of the Foundation, but the Foundation was authorized to collect payment from the accounts of insurance companies to compensate member-doctors for services that were provided to patients with approved medical insurance. Patients who had Foundation-approved medical insurance and saw member-doctors were guaranteed complete coverage for medical services at prices listed in the Foundation’s fee schedule. The State of Arizona (plaintiff) believed that the Foundation’s fee schedule was actually increasing prices charged by physicians, which in turn increased insurance premiums paid by patients. In an attempt to shut down the program, Arizona brought a suit against the Foundation, alleging that the fee schedule violated antitrust law.