We propose a simple theory of predatory pricing, based on incumbency advantages, scale economies and sequential buyers (or markets). The  prey needs to reach a critical scale to be successful. The incumbent  (or predator) has an initial advantage and is ready to make losses on earlier buyers so as to deprive the prey of the scale the latter needs, thus making monopoly pro ts on later buyers. Several extensions are considered, including cases where scale economies exist because of demand externalities or two-sided market effects, and where markets are characterized by common costs. Conditions under which predation may (or not) take place in actual cases are also discussed.
 

VIEW PAPER