In The Antitrust Paradox, Robert Bork viewed most mergers as either competitively neutral or efficiency enhancing. In his view, only mergers creating a dominant firm or monopoly were likely to harm consumers. Bork was especially skeptical of oligopoly concerns resulting from mergers. In this...

Empirical exercises in economics frequently involve estimation of highly nonlinear models. The criterion function may not be globally concave or convex and exhibit many local extrema. Choosing among these local extrema is non-trivial for a variety of reasons. In this paper, we analyze the...

This paper empirically investigates the possible market power effects of vertical integration proposed in the theoretical literature on vertical foreclosure. It uses a rich data set of cement and ready-mixed concrete plants that spans several decades to perform a detailed case study. There is...

Incompatibility in market with network effects reduces consumers' ability to "mix and match" components offered by different sellers, but can also spur changes in product attributes that might benefit consumers. In this paper, we estimate the effects of incompatibility on consumers in a classic...

This paper reviews recent methodological developments in the empirical analysis of imperfectly competitive markets highlighting outstanding problems. Some of these problems are econometric; e.g. the need for a deeper understanding of the small sample properties of our estimators. Most of the...

We test whether firms use incompatibility strategically, using data from ATM markets. High ATM fees degrade the value of competitors' deposit accounts, and can in principle serve as a mechanism for siphoning depositors away from competitors or for creating deposit account differentiation. Our...

This paper analyzes the concept of barriers to entry. It explains that the concept is a static one and explores the inadequacy of the concept in a world with sunk costs, adjustment costs and uncertainty. The static concept addresses the question of whether profits are excessive. The more...

This paper investigates the role of product upgrades and consumer switching costs in the tying of complementary products. Previous analyses of tying have found that a monopolist of one product cannot increase its profits and reduce social welfare by tying and monopolizing a complementary product...

U.S. v. Microsoft and the related state suit filed in 1998 appear finally to have concluded. In a unanimous en banc decision issued in late June 2004, the D.C. Circuit Court of Appeals rejected challenges to the remedies approved by the District Court in November 2002. The wave of follow-on...

The challenge of effective merger enforcement is tremendous. U.S. antitrust agencies must, by statute, quickly forecast the competitive effects of mergers that occur in virtually every sector of the economy to determine if mergers can proceed. Surprisingly, given the complexity of the regulators...