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,...

We consider differentiated duopolists facing symmetric linear demands and using Cobb-Douglas technologies with two inputs: a monopolized input and a competitively supplied input. Unlike with fixed-proportions technologies, a merger between the input monopolist and either firm can reduce welfare....