M0 is the most liquid measure of the money supply including coins and notes in circulation and other assets that are easily convertible into cash. Money Supply M0 is also known as narrow money. The monetary base, or M0, is equal to coin currency, physical paper, and central bank reserves. Also known as M0, narrow money refers to physical money, such as coins and currency, demand deposits, and other liquid assets, that are easily accessible to central banks. Narrow money is a subset of broad money that includes long-term deposits and other deposit-based accounts