Container Corporation of America (Container Corp.) (defendant) is a manufacturer of shipping containers. Container Corp. and 17 other container manufacturers (defendants) maintained a practice of sharing pricing information with each other upon request. There was no formal agreement between the container manufacturers, but each of the competitors generally provided the price information with the understanding that a request for information would be reciprocated in the future. Together, the container manufacturers constituted 90 percent of the relevant market. The United States (plaintiff) brought a complaint against the container manufacturers, alleging that the price-sharing practice constituted unlawful concerted action in violation of § 1 of the Sherman Act. The government’s claim was dismissed by the district court, and the government appealed the decision.