When used in the health care industry, an MFN clause is a contractual agreement that guarantees a health insurer the same best price as their market competitors. MFN clauses have the effect of unnecessarily raising consumer costs, reducing choice among providers, constraining access to care and preventing the development of alternative health care delivery models. The purpose of this paper is four-fold. First, to design a four-quadrant matrix to evaluate the pro-competitive and anticompetitive purposes and effects of MFN clauses under Section 1 of the Sherman Act. Second, to defeat the jurisprudential presumption that MFN clauses are pro-competitive in the health care industry and to recommend that this presumption be abolished. Third, to examine the U.S. Department of Justice's paradigmatic shift over the last decade toward prosecuting large insurers who employ MFN clauses resulting in U.S. Consent Decrees. Fourth, to outline the indicia of a meritorious claim against an insurer who employs an MFN clause.