Surplus Bounds in Cournot Monopoly and Competition

We characterize equilibria of oligopolistic markets where identical firms with constant marginal cost compete a’ la Cournot. For given maximal willingness to pay and maximal total demand, we first identify all combinations of quilibrium consumer and producer surplus that can arise from arbitrary demand functions. Then, as a further restriction, we fix the average willingness to pay above marginal cost (i.e., first best surplus) and identify all possible triples of consumer surplus, producer surplus and deadweight loss.