Commercial banks differ widely in how they manage liquidity. A small bank derives its funds primarily from customer deposits, normally a fairly stable source in the aggregate. Its assets are mostly loans to small firms and households, and it usually has more deposits than it can find creditworthy borrowers for. Excess funds are typically invested in assets that will provide it with liquidity such as Fed funds loaned and U.S. government securities. The holding of assets that can readily be turned into cash when needed, is known as asset management banking.