We propose a simple, new test for making an initial determination of whether a proposed merger between rivals is likely to reduce competition and thus lead to higher prices. Under current antitrust policy, the government can establish a presumption that a proposed horizontal merger will harm...

Economists at the Federal Trade Commission pursue the agency’s competition and consumer protection missions. In this year’s essay, in antitrust, we discuss two recent mergers that involved Rx drugs: First, we describe key elements of the inquiry into the Express Scripts/Medco transaction in...