The monopolistic competition model in international trade offers three sources of gains from trade that do not arise in competitive models: expansion in product variety; a pro-competitive reduction in the markups charged by firms; and the self-selection of more efficient firms into exporting....

In a model where all factors of production are imperfectly mobile, we argue that the Dixit-Norman scheme of commodity taxes may not lead to strict Pareto gains from trade. Rather, this scheme must be augmented by policies which give factors an incentive to move: hence, the role for trade...

Three sources of gains from trade under monopolistic competition are: (i) new import varieties available to consumers; (ii) enhanced efficiency as more productive firms begin exporting and less productive firms exit; (iii) reduced markups charged by firms due to import competition. The first...