On the social optimality of make-or-buy decisions

This article examines the impact of input prices on an entrant’s make-or-buy decision and on the subsequent social welfare level for three alternative models of downstream competition. For each particular model, it derives the range of input prices that induce the entrant to undertake: (a) the productively efficient make-or-buy decision; and (b) the socially optimal make-or-buy decision. The main conclusion of this article is that the entrant’s efficient make-or-buy decision is always socially optimal in the case of the Hotelling model, is socially optimal for the set of input prices that induce the entrant to undertake the efficient decision in the case of Cournot competition and is not necessarily socially optimal in the Bertrand vertical differentiation model. Last, this article examines the conditions under which the efficient and/or socially optimal make-or-buy decision undertaken by an entrant fulfills the regulatory two-fold goal of promoting service-based competition and encouraging facilities-based competition. Therefore, this article also provides the optimal access pricing policy that results in the best feasible outcome in terms of social welfare, productive efficiency, competition level and investment level for a given downstream competition model.