On Welfare under Cournot and Bertrand Competition in Differentiated Oligopolies

Hackner (2000) shows that in a differentiated oligopoly with more than two firms , prices may be higher under Bertrand competition than under Cournot competition, implying that the classical result of Singh and Vives (1984) that Bertrand prices are always lower than Cournot prices is sensitive to the duopoly assumption. Hackner (2000), however, leaves unanswered the important question of whether welfare may be lower under price competition. This note shows that in Hackners model both consumer surplus and total surplus are higher under price competition than under quantity competition regardless of whether goods are substitutes or complements.