China is discussing ways in which a new regional lender being pushed by Beijing can cooperate with the Asian Development Bank (ADB), Finance Minister Lou Jiwei said on Sunday, as he sought to fend off concerns that the two banks would become rivals. Some 27 countries have now signed up to participate in the Asian Infrastructure Investment Bank (AIIB), a $50 billion fund slated to begin operations at the end of the year providing project loans to developing countries.