Towards a welfare model of trade and multinational firms with oligopolistic competition

This paper constructs a general equilibrium model in a world with two-symmetric countries. It explains welfare gains from international trade and horizontal Foreign Direct Investment (FDI) in the economy with firm heterogeneity and variable markups stemming from oligopolistic competition. My model shows that the pro-competitive effects of trade and horizontal FDI happen because trade openness induces an increase in product market competition that reduces markups and toughens selection, increasing aggregate productivity. The most significant contribution of the paper is that multinational firms, via horizontal FDI, produce the most significant welfare gains through the toughest selection and lowest markups.