In case decided under Rule of Reason, the threshold issue is market power. Market power is defined as the ability to raise prices above the competitive level by restricting output. ''Wilk v. American Medical Ass'n'', 895 F.2d 352, 359 (7th Cir.), cert. denied, 496 U.S. 927 (1990). | In case decided under Rule of Reason, the threshold issue is market power. Market power is defined as the ability to raise prices above the competitive level by restricting output. ''Wilk v. American Medical Ass'n'', 895 F.2d 352, 359 (7th Cir.), cert. denied, 496 U.S. 927 (1990). |