Fragmentation and Welfare in Monopolistic Competition

We examine the welfare effect of fragmentation with a general-equilibrium model of monopolistic competition. Using the efficiency property of monopolistic competition models, we develop a diagram that is used to show that fragmentation of production arises, i.e. firms in a country specialize in developing blueprints and out-source the manufacturing of their products to the other country. Such fragmentation allows countries to benefit from trade due to two different sources: comparative advantage and product diversity. We show how these two sources result in gains from trade induced by this production fragmentation.