Several corporate entities and subsidiaries (AT&T) (defendant) owned a large amount of the infrastructure and facilities that were necessary to provide digital subscriber line (DSL) Internet services. As a condition of a merger, AT&T was bound by an abandoned requirement of the Federal Communications Commission (FCC) to sell the use of AT&T’s infrastructure to independent DSL providers that were competing against AT&T in the retail market for DSL service. AT&T competed at both wholesale and retail levels by offering infrastructure and facilities to independent DSL providers at the wholesale level while also selling DSL to consumers at the retail level. Linkline Communications, Inc., and four other DSL providers (the retailers) (plaintiffs) were among the independent DSL providers who purchased access to AT&T’s system in order to provide their own DSL service. In 2003, the retailers brought a lawsuit against AT&T, alleging that AT&T was using its position in the wholesale and resale markets for DSL service to price squeeze individual DSL providers out of the retail market in order to further AT&T’s monopoly in DSL access. The district court found for the retailers, and the court of appeals affirmed. AT&T appealed.