Downstream rivals’ competition, bargaining, and welfare

We analyze the effect of downstream competition (or cooperation) in the presence of decentralized bargaining between two downstream firms and an upstream monopolist over a two-part tariff input price. The major findings are as follows: (i) the relationship between the profits of the upstream monopolist (resp. the downstream firms) and the intensity of competition is U-shaped (resp. inverted U-shaped), irrespective of the competition modes in the downstream product market; (ii) if the intensity of competition is sufficiently high, the downstream firms’ profits are higher under Bertrand competition, whereas if the intensity of competition is sufficiently low, the downstream firms’ profits are higher under Cournot competition; and (iii) a market under Cournot competition is more efficient than a market under Bertrand competition, in the sense that both consumer surplus and social welfare are higher in the case of the former.