Trade agreements when profits matter

This paper suggests a rationale for the GATT/WTO ban on export subsidies by showing that, in a linear Cournot profit-shifting model in which countries invest in a policy infrastructure before imposing trade policy, an agreement banning export subsidies tends to be more self-enforcing than one banning tariffs. Oligopoly introduces asymmetry between import tariffs and export subsidies: terms-of-trade and profit-shifting effects run in the same direction for import tariffs but in opposite directions for export subsidies. This asymmetry and the fact that it takes time for countries to change their trade policy infrastructure imply that the payoffs on the off-equilibrium path under an import-tariff-only agreement tend to be lower than those on the off-equilibrium path under an export-subsidy-only agreement. Specifically, punishment with tariffs is harsher than punishment with subsidies. When the set of instruments is restricted to import tariffs, a trade agreement needs to neutralize both the terms-of-trade and profit-shifting externalities.