A Per Se violation is conduct that falls within a category deemed to be Per Se unlawful--that is, conduct so bad that the conduct itself constitutes a Sherman Act violation even if the activities contemplated were not pursued or the conduct did not have an anti-competitive effect.

The Rule of Reason analysis requires inquiry into the reasonableness of the business practices and requires courts to actually balance the merits of the proposed conduct versus any potential anti-competitive effects it may have. If the anti-competitive effect outweighs the benefits, the conduct is deemed to violate the Sherman Act.