Trade agreements when profits matter
在线性古诺利润转移模型中解释了GATT/WTO禁止出口补贴的原因，发现禁止出口补贴的协定比禁止关税的协定更易自我执行，因为寡头市场下关税和补贴的效应不对称，且改变政策基础设施需要时间。
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.