West Penn Allegheny Health System, Inc. (West Penn) (plaintiff), Pittsburgh, Pennsylvania’s second-largest hospital system, filed suit in federal district court under § 1 of the Sherman Antitrust Act, which prohibits actions in restraint of trade, against University of Pittsburgh Medical Center (UPMC) (defendant), the city’s dominant hospital system and Highmark, Inc. (defendant), the dominant health insurer in Allegheny County where Pittsburgh is located. Specifically, West Penn alleged that UPMC conspired with Highmark to take significant and devastating financial actions to insulate each other from competition. West Penn also alleged that Defendants violated § 2 of the Sherman Act by attempting to monopolize the area market for specialized hospital services. The district court dismissed the complaint. West Penn appealed.