Per se rule
The per se rule under the Sherman Act treats a business practice as automatically unlawful without any judicial inquiry into the motives or justification for the business. The per se rule is confined to restraints "that would always or almost always tend to restrict competition and decrease output." Business Electronics Corp. v. Sharp Electronics Corp., 485 U.S. 717 at 723 (1988) (internal quotation marks omitted). To justify a per se prohibition a restraint must have "manifestly anticompetitive" effects, Continental T. V., Inc. v. GTE Sylvania Inc., 433 U.S. 36, 50 (1977), and "lack ... any redeeming virtue," Northwest Wholesale Stationers, Inc. v. Pacific Stationery and Printing Co., 472 U.S. 284, 289 (1985) (internal quotation marks omitted).
The per se rule is appropriate only after courts have had considerable experience with the type of restraint at issue, see Broadcast Music, Inc. v. Columbia Broadcasting System, Inc., 441 U.S. 1, 9 (1979), and only if courts can predict with confidence that it would be invalidated in all or almost all instances under the rule of reason, see Arizona v. Maricopa County Medical Soc., 457 U.S. 332, 344 (1982). Courts "have expressed reluctance to adopt per se rules with regard to restraints imposed in the context of business relationships where the economic impact of certain practices is not immediately obvious." Khan, supra, at 10 (internal quotation marks omitted); see also White Motor Co. v. United States, 372 U.S. 253, 263 (1963) (refusing to adopt a per se rule for a vertical nonprice restraint because of the uncertainty concerning whether this type of restraint satisfied the demanding standards necessary to apply a per se rule). The Court has stated, a "departure from the rule-of-reason standard must be based upon demonstrable economic effect rather than ... upon formalistic line drawing." GTE Sylvania, supra, at 58-59.