The paper takes as its starting point the Irish telecom regulator ComReg's finding of joint dominance by two firms in the mobile phone market in Ireland. The paper argues that the regulator's decision was inconsistent with the facts in the case. However, it argues that the case raises wider...

We consider a dynamic platform competition in a market with network externalities. The incumbent platform enjoys a focal position such that consumers expect other consumers to join it, while the entrant platform may enjoy a quality advantage. We examine the effect of an antitrust policy that...