In 1962, the owners of four major mountains in Aspen, Colorado began offering an interchangeable ski-lift ticket that could be used at each of the four mountains. In 1964, Aspen Skiing Company (Ski Co.) (defendant) purchased one of the mountains to bring Ski Co.’s ownership to three of the four mountains in the Aspen area. Ski Co. and Highlands Skiing Corporation (Highland) (defendant), the only remaining competitor in the market for Aspen skiers, continued to offer the interchangeable ticket. The proceeds were distributed based on the usage of each mountain by skiers with interchangeable tickets. In 1978, Ski Co. offered Highland a fixed percentage of the revenue from interchangeable tickets that was substantially below the revenue typically received by Highland based on actual usage. After Highland rejected the offer, Ski Co. discontinued the interchangeable-ticket program and established a new program that allowed skiers to purchase an interchangeable pass for Ski Co.’s mountains but not for Highland’s mountain. Additionally, Ski Co. refused to sell lift tickets for Ski Co.’s mountains to Highland at any price or accept the vouchers that Highland offered to skiers. As a result, Highland’s market share for skiing in the Aspen area declined dramatically. Highland brought a complaint against Ski Co., alleging that Ski Co. had violated § 2 of the Sherman Act by monopolizing skiing in the Aspen area. A jury found Ski Co. guilty and awarded Highland treble damages. The court of appeals affirmed the decision. Ski Co. appealed.