On the optimal external tariff of a free trade area with internal market integration

Previous analyses of free trade areas suggest that member countries reduce external tariffs to the level that improves welfare of non-member countries. Using an oligopoly model with product differentiation, this paper shows that when a free trade area entails endogenous change from segmented to integrated markets for internally produced goods, external tariffs become strategic complements and their equilibrium level is higher than in the market segmentation case. In this case, the non-member may lose from the formation of free trade area whereas each member gains more.