AIIB cooperation with legacy institutions

The Asian Infrastructure Investment Bank (AIIB) is typically understood as a competitor to legacy institutions, like the World Bank, that are cornerstones to the liberal international order. However, novel project-level data on AIIB lending show that it frequently cooperates with these legacy institutions. Cooperative projects are much more frequent than previously assumed—making up around one-third of AIIB projects. Why does the AIIB cooperate with legacy institutions? We theorize and test four distinct motivations for cooperation: (1) legitimacy-driven, (2) mandate-driven, (3) resource-driven, and (4) staff-driven cooperation. Our research design utilizes original data on cooperation between the AIIB and the World Bank, Asian Development Bank and European Bank of Reconstruction and Development between 2016 to 2023. We show that cooperative efforts do not follow a global trend but rather vary substantially between country contexts. Our findings have broader implications for debates on contestation of legacy institutions by emerging powers.