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...

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...

Market definition has long held a central place in competition law. This entry surveys recent analytical work that has called the market definition paradigm into question on a number of fronts: whether the process is feasible, whether market share threshold tests are coherent, whether the...

The value of sales of an undertaking infringing antitrust law is a key determinant of the size of the fine levied by a competition authority. European competition authorities rely only on the turnover the undertaking receives from the products in relation to which the infringing conduct...

This paper considers the effect of taxes on the definition of relevant markets in antitrust analysis by examining various measures used within the hypothetical monopoly test. We show that the use of net margins (between producer prices and marginal cost) is a proper correction, but that it is...

Monopolization, in the United States, and abuse of dominance, in the European Union, embody different philosophies about how best to police single firm conduct in competition law. Surprisingly, their disagreement ends at market definition. Both doctrines define relevant markets by similar...

Economic analysis of competition regulation is most developed in the domain of horizontal mergers, and modern agency guidelines reflect a substantial consensus on the appropriate template for merger assessment. Nevertheless, official protocols are understood to rest on a problematic market...

Telecom companies are a frequent target of antitrust investigations in Russia. In an industry where services tend to become more and more complex and companies actively invest in diversifying their businesses, the antitrust authority in most of its telecom cases has chosen to define markets...

An increasing body of empirical evidence is documenting trends toward rising concentration, profits, and markups in many industries around the world since the 1980s. Two major criticisms of these studies is that concentration and market shares are poorly measured at the national industry level...