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...

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...

We examine whether and to what extent consolidation in the U.S. health insurance industry is leading to higher employer-sponsored insurance premiums. We make use of a proprietary, panel dataset of employer-sponsored healthplans enrolling over 10 million Americans annually between 1998 and 2006...

Theoretical investigations have examined both anti-competitive and efficiency-inducing rationales for vertical bundling, making empirical evidence important to understanding its welfare implications. We use an extensive dataset on full-line forcing contracts between movie distributors and video...

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...

Market definition is essential to merger analysis. Because no standard approach to market definition exists, opposing parties in antitrust cases often disagree about the extent of the market. These differences have been particularly relevant in the hospital industry, where the courts have denied...

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...