Port Competition and Hinterland Reconfiguration in the GMS: A Tripolar Balance

บทคัดย่อ

This paper studies how integration shocks reshape cross-border spatial equilibria in the Greater Mekong Subregion (GMS). Specifically, we examine whether new gateway capacity generates winner-takes-all dominance or stabilizes a polycentric (tripolar) configuration. Exploiting the 2015 deep-water expansion of Sihanoukville Port (SHV), we quantify hinterland responses across 47 inland provinces in Cambodia, Lao PDR, and Northeast Thailand over 2012–2021. To overcome cross-country data scarcity, we combine harmonized VIIRS night-time lights with a multi-period event-study difference-in-differences design, defining treatment intensity by pre-event road distance to SHV. Robustness analyses explicitly address local port-city confounding (donut restrictions) and spatial dependence. Empirically, we document persistent post-2015 growth concentrated along intermediate-distance corridor belts, confirming network-mediated spillovers rather than localized port-city shocks. This emergence of an additional growth pole refutes zero-sum displacement, motivating a governance approach that leverages gateway expansions to institutionalize regional balance and resilience in the GMS.