In recent decades, States have concluded numerous regional investment treaties, even as the feverish growth in bilateral investment treaties worldwide continues apace. This increasing regionalism within international investment law is a double-edged phenomenon. On the one hand, the risks of fragmentation and incoherence increase exponentially as a regional layer is added to the already-messy “spaghetti bowl” of investment treaties. The noble dream of a uniform, multilateralized set of investment-protection standards thus looks ever more unattainable. On the other hand, a regional investment treaty affords an opportunity for a group of States to balance, in a particularistic manner, between investment-related obligations and other non-investment priorities. This essay focuses on the ASEAN Comprehensive Investment Agreement signed in 2009, arguing that it is a region-specific bargain embedded within ASEAN's wider normative and institutional framework. The potential conflicts between ASEAN Member States' investment-related obligations and their commitments under two other regional projects are explored, and recommendations are made as to how arbitral tribunals can manage such conflicts.