West Penn Allegheny Health System, Inc. v. UPMC; Highmark, Inc.

West Penn (plaintiff), Pittsburgh's second-largest hospital system, alleged that UPMC (defendant), the dominant hospital system, and Highmark (defendant), the dominant insurer, conspired to take actions insulating each other from competition; specifically, Highmark refused to raise West Penn's below-market reimbursement rates -- even though it agreed the rates were too low -- out of fear of UPMC retaliation. West Penn also alleged UPMC separately attempted to monopolize the market for specialized hospital services with intent to drive West Penn out of business. The district court dismissed the complaint, and West Penn appealed.

Whether a Sherman Act sections 1 and 2 violation results when one entity conspires with another to achieve monopoly power and unreasonably restrain trade within a specific geographic market.