We analyse competition between perfectly substitutable networks. Monopolization can be sustained in equilibrium by asymmetric access prices whereby entry is deterred by a set of margin squeezes. A regulatory package consisting of (i) mandatory interconnection; (ii) reciprocal access prices;...

A general theoretical and empirical framework is developed for assessing the potential of a vertically integrated firm to foreclose downstream competitors. Using this framework a policymaker may also evaluate the empirical welfare effects from a vertically integrated firm raising rivals' costs....