Do South‐South preferential trade agreements undermine the prospects for multilateral free trade?

Due to trade diversion, there have been concerns expressed over the proliferation of preferential trade agreements (PTAs) that include South countries. In this paper, we compare welfare across different geographic configurations of bilateral free trade agreements (FTAs) and customs unions (CUs) and examine their implications for the stability of multilateral free trade. While North–North PTAs do tend to yield higher global welfare than South–South PTAs, a single South–South FTA may make free trade more sustainable than any other single agreement. With pre‐existing North–North agreements and a large enough cost asymmetry between regions, an additional South member or a new South–South agreement always makes free trade harder to sustain.