What is the test for establishing that a patentee has market power?

We also observe that the outlined prima facie showing will suffice, without more, to raise a presumption of the patentee's market power. Proving that a restraint has anticompetitive effects often requires the plaintiff to delineate a relevant market and show that the defendant plays enough of a role in that market to impair competition significantly, i.e., has market power. (Roth v. Rhodes, supra, 25 Cal.App.4th at p. 542, 30 Cal.Rptr.2d 706.) Here, proof of a sufficiently large payment is a surrogate: the size of the payment from a branded drug manufacturer to a prospective generic is itself a strong indicator of powernamely, the power to charge prices higher than the competitive level.

[61 Cal.4th 158]