Optimum-welfare and maximum-revenue tariffs under Bertrand duopoly

This article derives the maximum-revenue tariff and the optimum-welfare tariff under Bertrand duopoly with differentiated products. It is shown that both tariffs are lower under Bertrand duopoly than under Cournot duopoly. Also, the optimum-welfare tariff may exceed the maximum-revenue tariff under both Bertrand duopoly and Cournot duopoly. This result is more likely the lower the costs of the home firm relative to the costs of the foreign firm, and the greater the degree of product substitutability. Also, it is shown that the optimum-welfare tariff is less likely to exceed the maximum-revenue tariff under Bertrand duopoly than under Cournot duopoly.