Network externalities, dominant value margins, and equilibrium uniqueness

We examine tippy network markets that accommodate price discrimination. The analysis shows that when a mild equilibrium refinement, the monotonicity criterion, is adopted, network competition may have a unique subgame-perfect equilibrium regarding the winner's identity; the prevailing brand may be fully determined by its product features. We bring out the concept of the dominant value margin, which is a metric of the effectiveness of divide-and-conquer strategies. The supplier with the larger dominant value margin may always sell to all customers in equilibrium. Such a market outcome is not always socially efficient since a socially inferior supplier may prevail if has a stand-alone-benefit advantage and only a modest network-benefit disadvantage.