The number of free trade agreements (FTAs) has increased in the past few decades, and the cross-country variation of the most-favored-nation (MFN) tariffs has decreased. Motivated by these two facts, we study whether the reduced variance in cross-country MFN tariffs can help explain the expansion of FTAs. Using an oligopolistic trade model with the equilibrium concept of pairwise stable networks, we reveal the existence of a set of pairwise stable network equilibria, where the number of FTAs rises as tariffs become increasingly symmetrical. This finding contributes to theoretical FTA literature by showing that an incomplete FTA network can be supported as a pairwise stable network equilibrium.

过去几十年，自由贸易协定 (FTA) 的数量有所增加，最惠国 (MFN) 关税的跨国差异有所减少。受这两个事实的启发，我们研究了跨国最惠国关税差异的减少是否有助于解释自由贸易协定的扩大。使用具有成对稳定网络均衡概念的寡头贸易模型，我们揭示了一组成对稳定网络均衡的存在，其中自由贸易协定的数量随着关税变得越来越对称而增加。这一发现通过表明不完整的 FTA 网络可以作为成对稳定的网络平衡来支持，从而有助于理论 FTA 文献。