Ps represent a putative class consisting of all “subscribers of local telephone and/or high-speed internet services. Ps seek damages and declaratory and injunctive relief for claimed violations of §1 of the Sherman Act. Ps alleged that Ds conspired to restrain trade by inflating charges for local telephone and high-speed Internet services. Ps alleged that Ds “engaged in parallel conduct” to inhibit the growth of upstart CLECs. Ps also alleged that Ds failed to refrain from competing against one another. Ps alleged upon information and belief that Ds have entered into a contract, combination or conspiracy to prevent competitive entry in their respective local telephone and/or high-speed internet services markets and have agreed not to compete with one another and otherwise allocated customers and markets to one another. The District Court dismissed the complaint in that allegations of parallel business conduct, taken alone, do not state a claim under §1. Ps must allege additional facts that “tend to exclude independent self-interested conduct as an explanation for defendants’ parallel behavior.” The Court of Appeals reversed, holding that the District Court tested the complaint by the wrong standard. It held that “plus factors are not required to be pleaded to permit an antitrust claim based on parallel conduct to survive dismissal.” Ps must plead facts that “include conspiracy among the realm of ‘plausible’ possibilities in order to survive a motion to dismiss.” “To rule that allegations of parallel anticompetitive conduct fail to support a plausible conspiracy claim; a court would have to conclude that there is no set of facts that would permit a plaintiff to demonstrate that the particular parallelism asserted was the product of collusion rather than coincidence.” The Supreme Court granted certiorari.