The Asian Infrastructure Investment Bank (AIIB) is a multilateral development bank and international financial institution that aims to collectively improve economic and social outcomes in Asia. It is the world's second largest multi-lateral development institution. Headquartered in Beijing, China, the bank currently has 110 members, including 12 prospective members from around the world. The breakdown of the 110 members by continents are as follows: 42 in Asia, 26 in Europe, 22 in Africa, 10 in Oceania, 8 in South America, and 2 in North America. The bank started operation after the agreement entered into force on 25 December 2015, after ratifications were received from 10 member states holding a total number of 50% of the initial subscriptions of the Authorized Capital Stock.