Excess Entry, Vertical Integration and Welfare

This article provides a systematic analysis of the welfare effects of vertical integration by a monopolist input supplier into a monopolistically competitive downstream industry. We give sufficient conditions on consumer preferences that lead to Pareto-improving vertical integration and demonstrate a close relationship between assumptions on preference for variety, excess entry in monopolistically competitive markets, and the welfare effects of vertical integration: Excess entry in downstream markets tends to give rise to Pareto-improving vertical integration. We extend the analysis to vertical oligopoly and access price regulation.