mostly made up of loan, leasing, business investment and government bonds.
Banks make money and contribute a lot to countrys economy by getting benefit as transaction cost from many users who send money here and there or all over the world.
Furthermore, they cut annual or sometime somewhere monthly costs per their bank rules. Through these ways banks contribute to economy and have great part in building up countries. They bring new innovations like insurance as well as other schemes where there is possibility to make some money.