Spatial competition and social welfare in the presence of non-monotonic network effects

We study a spatial duopoly and extend the literature by giving joint consideration to non-monotonic network effects and endogenous firm location decisions. We show that the presence of network effects (capturing, for example, in-store rather than online sales) improves welfare whenever the total market size is not too large. This effect is lost if network effects are specified in a monotonic fashion, in which case isolating consumers from one another always reduces welfare. We also provide a new rationale for a duopoly to be welfare-preferred to monopoly: in large markets, splitting demand between two firms can reduce utility losses due to crowding.