International trade, income distribution and welfare

This paper studies the relationship between income distribution and international integration in a canonical trade setting with one change. In the standard model prices are solely a function of (constant) marginal costs and (constant) elasticities, implying that information on individual incomes are of no value to a firm. To allow a more realistic role for consumer level information, a firm's strategy space is expanded to include non-linear prices. Now profit maximizing firms use information on income distribution to design a product for each income class and set prices to induce each group to optimally select the appropriate option. Equilibrium involves designs below the first best for low income groups and above the first best for high income groups - welfare differences are more exaggerated than income differences. When countries with differing income distributions integrate this has implications for the size of these distortions, influencing the gains from trade both within and across countries. These implications are quantified and shown to be potentially significant factors affecting welfare outcomes from integration - with the consequences more pronounced at lower trade costs. The structure of trade and expenditure patterns that emerge also match a range of empirical findings. These results are driven by firm strategy based on income difference alone as preferences are assumed to be identical and homothetic across countries, placing the distribution of income at the center of the analysis.