Knowledge that a particular course of conduct has been followed by a competitor combined with an independent decision by another party to follow the same course of conduct; it is distinguished from conspiracy, which requires an agreement, either tacit or express, between the parties engaged in the parallel conduct. See 346 U.S. 537, 540-41.
Conscious parallelism alone is not a violation of the antitrust statutes. See 75 Harv. L. Rev. 655 (1962). Evidence of such consciously parallel conduct, however, is highly probative on the issue of whether an actual conspiracy did exist. See 306 U.S. 208.




