The Asian Infrastructure Investment Bank (AIIB) is a multilateral development bank that aims to improve economic and social outcomes in Asia.The bank currently has 105 members, including 16 prospective members from around the world.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.The United Nations has addressed the launch of AIIB as having potential for "scaling up financing for sustainable development" and to improve the global economic governance.The starting capital of the bank was US$100 billion, equivalent to 2⁄3 of the capital of the Asian Development Bank and about half that of the World Bank.The bank was proposed by China in 2013 and the initiative was launched at a ceremony in Beijing in October 2014. It received the highest credit ratings from the three biggest rating agencies in the world, and is seen as a potential rival to the World Bank and IMF.