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 consider an upstream firm U that supplies a key input to two symmetric downstream firms, A and B, that sell differentiated products. U negotiates bilaterally with A and B over a linear input price, and A and B set output prices. We assume Nash-in-Nash bargaining for input prices, and Bertrand...

Most quantitative tools for assessing competitive effects of mergers rely heavily on recapture ratios (also known as aggregate diversion ratios). Recapture ratios measure the proportion of customers switching away from a product that is captured by other products within the market rather than...

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,...