We study optimal merger policy in a dynamic model in which the presence of scale economies implies that firms can reduce costs through either internal investment in build- ing capital or through mergers. The model, which we solve computationally, allows firms to invest or propose mergers...

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...