The Value of Incumbency When Platforms Face Heterogeneous Customers

We study competition for the market in a dynamic model with network externalities, focusing on the efficiency of market outcomes. We propose a representation of the strategic advantages of incumbency and embed it in a dynamic framework with heterogeneous consumers. Then, we completely identify the conditions under which inefficient equilibria with several platforms emerge at equilibrium; explore the reasons why these inefficient equilibria arise; and compute the value of incumbency and analyze why static models generally exaggerate it. (JEL D43, D62, L13, L86)