On March 20, 2011, wireless provider AT&T announced its intention to merge with T-Mobile USA, a competing wireless provider. This article reviews the economic analysis of this proposed acquisition that we carried out for Sprint and explains why the merger would have been anticompetitive. We...

In this short and mainly expository article, we explain the “hypothetical monopolist test” that has become the standard methodology for identifying relevant antitrust markets in merger cases, and discuss two approaches to implementing the test. We then focus on the implementation of the test...

We present a model of ordered bargaining between one buyer and several sellers, with Nash bargaining at each stage. We first show that the model has the property that the buyer's payoff equals the expected utility of a weighted sum of independent Bernoulli random variables. We then exploit this...

This note describes the implementation of the hypothetical monopolist ssnip test for market definition in the context of merger cases where firms produce multiple differentiated products. The test developed here represents an extension and generalization of the Katz-Shapiro and...

We examine the role of private information on the impact of vertical mergers. A vertical merger can improve the information that is available to an upstream monopolist because, after the merger, the monopolist can observe the cost of its downstream merger partner. In the pre-merger world,...

This article explains the inherent loss of an indirect competitor and reduction in competition when a vertical merger raises input foreclosure concerns. We then calculate a measure of the effective increase in the HHI measure of concentration for the downstream market, and we refer to this...

One key concern in vertical merger cases is input foreclosure. Input foreclosure involves raising the costs of competitors in the downstream market, which could in turn increase the sales and profits of the downstream merger partner. In this article, we explain how the upward pricing pressure...