This paper studies how firm heterogeneity in terms of productivity affects the balance between agglomeration and dispersion forces in the presence of pecuniary externalities through a selection model of monopolistic competition with endogenous markups. It shows that firm heterogeneity matters....

In this Paper, we show that with international externalities, different country sizes, imperfect competition and trade costs, tax competition for mobile firms is efficiency enhancing with respect to the free market outcome. Nonetheless, while the latter entails too many firms in the larger...