Three years ago, the Antitrust Division and the Federal Trade Commission revised their Horizontal Merger Guidelines to articulate in greater detail how they would treat claims of efficiencies associated with horizontal mergers: claims that are frequently made, as for instance in the recently...

We describe a simple initial indicator of whether a proposed merger between rivals in a differentiated product industry is likely to raise prices through unilateral effects. Our diagnostic calibrates upward pricing pressure (UPP) resulting from the merger, based on the price/cost margins of the...

We describe how the hypothetical monopolist test used to define relevant markets in horizontal merger cases can be implemented using the fundamental economic concepts of opportunity cost and pass-through. Unlike critical loss analysis, our approach analyzes the behavior of a profit-maximizing...

We study how the courts have responded to the 2010 Horizontal Merger Guidelines issued by the U.S. Department of Justice and the Federal Trade Commission. Looking at decided cases, we find that both the government and merging parties rely on the 2010 Guidelines in presenting their cases, each...

This is a survey of the economic principles that underlie antitrust law and how those principles relate to competition policy. We address four core subject areas: market power, collusion, mergers between competitors, and monopolization. In each area, we select the most relevant portions of...