This paper proposes two theoretical considerations regarding Multilateral development banks (MDBs). The first is that MDB activities are increasingly driven by the growing economic strength of many developing countries. The second is that categorizing MDBs according to the balance of power among shareholders helps explain why countries might prefer one or another MDB. We compare three different MDBs operating in Latin America—one dominated by nonborrowers (World Bank), another controlled by borrowing countries (Andean Development Corporation, CAF), and a third more evenly split between borrowers and nonborrowers (Inter-American Development Bank, IADB). Qualitative and statistical analysis suggests that demand factors play an important role in MDB lending.