Money supply is the quantity of money outstanding in an economy at a particular time, measured using a specified definition of monetary assets and their holders. It commonly includes currency held by the public and deposit money, with broader measures incorporating additional liquid instruments. In macroeconomics, monetary aggregates help describe financial conditions and relationships between money, expenditure, and prices. There is no single universally applicable measure: definitions depend on institutional arrangements and statistical conventions. (federalreserve.gov)
Monetary aggregates
Monetary aggregates distinguish assets according to their liquidity—how readily they can be used for payments or converted into cash. Narrow measures emphasize immediately spendable balances; broader measures include assets that serve as close substitutes for transaction money. Labels such as M1, M2, and M3 do not necessarily identify equivalent instruments across countries. (ecb.europa.eu)
In the United States, the Federal Reserve defines:
- M1: currency outside the Treasury, Federal Reserve Banks, and depository institutions’ vaults; qualifying demand deposits; and other liquid deposits, including savings deposits.
- M2: M1 plus time deposits issued in amounts below $100,000 and retail money market fund balances, less specified individual retirement account and Keogh account balances.
These definitions include exclusions and accounting adjustments; simply adding every bank account balance would not reproduce the published aggregates. (federalreserve.gov)
In the euro area, M1 comprises currency in circulation and overnight deposits. M2 adds deposits with agreed maturities of up to two years and deposits redeemable at notice of up to three months. M3 adds repurchase agreements, money market fund shares or units, and debt securities issued by monetary financial institutions with maturities of up to two years. (ecb.europa.eu)
Money supply and the monetary base
The monetary base is distinct from money held by households and businesses. In the United States, it comprises currency in circulation plus reserve balances at the central bank. Bank reserves enable depository institutions to settle payments, but are not ordinary customer deposits available for household spending. Consequently, an increase in reserves need not produce an equal or proportionate increase in broad money. (federalreserve.gov)
The distinction concerns both the issuer and the holder. A customer’s deposit is a liability of a commercial bank; a bank’s reserve balance is a liability of the central bank. Transfers between customer accounts at different banks generally require settlement between the banks, connecting deposit money to the central-bank payment system without making the two instruments identical. (bankofengland.co.uk)
Creation and destruction of money
Commercial banks create deposit money when they extend loans. A new loan normally adds a loan asset to the bank’s balance sheet and a corresponding deposit liability. The borrower obtains purchasing power but also incurs debt; money creation therefore does not mean that the borrower receives equivalent net wealth. Repayment of loan principal reverses this process and destroys deposit money. (bankofengland.co.uk)
Bank lending is constrained rather than unlimited. Relevant constraints include bank capital, credit risk, funding and settlement needs, regulation, profitability, and demand from borrowers. A bank whose borrowers transfer funds elsewhere must obtain sufficient resources to settle those payments. Banks therefore do not merely lend out a fixed pool of prior savings, but neither can they create deposits without economic and institutional limits. (bankofengland.co.uk)
Textbook money multiplier models describe deposit expansion under restrictive assumptions about reserve ratios and banks’ behavior. They are not a general mechanical rule for modern banking systems: a given increase in the monetary base does not automatically generate a fixed multiple of new deposits. (bankofengland.co.uk)
Monetary policy
Monetary policy influences money creation through financing conditions and central-bank transactions. Changes in interest rates affect borrowing incentives, spending, and banks’ lending decisions. Open-market operations—conventionally identified by the entry ID open-market operations—and quantitative easing alter central-bank assets and liabilities; purchases from non-bank sellers can also create commercial-bank deposits. The broad-money effect depends on the counterparties and subsequent transactions, not solely on the size of the central bank’s balance sheet. (bankofengland.co.uk)
Many central banks pursue price stability using interest-rate instruments and frameworks such as inflation targeting, rather than fixing a monetary aggregate’s growth rate. Money-supply data remain informative, but policymakers examine them alongside output, prices, and other financial indicators. (imf.org)
Money, expenditure, and inflation
The quantity theory of money is associated with the equation of exchange:
where is a selected money stock, its velocity, a price measure, and real output. With consistent definitions, represents nominal gross domestic product, and velocity is nominal expenditure divided by the money stock. The equation alone does not establish causation. (imf.org)
Monetarism gives money growth a central explanatory role, particularly when velocity is sufficiently predictable. However, changing money demand and unstable velocity weaken simple relationships between monetary aggregates and expenditure. Monetary growth therefore cannot be translated mechanically into an identical contemporaneous rate of inflation or economic growth. (imf.org)
Statistical interpretation
Monetary time series require attention to classification changes, revisions, and seasonal adjustment. Starting with the May 2020 observation, the Federal Reserve included savings deposits in M1. This created a statistical break in M1 without changing M2 through that reclassification. A sharp measured increase can therefore reflect a definitional change rather than newly created money. (federalreserve.gov)
Published aggregates may also distinguish outstanding stocks from transactions and adjusted growth rates. The European Central Bank reports these separately and removes recurring seasonal patterns, such as predictable year-end movements. Comparisons across periods or economies depend on understanding the underlying definitions and statistical treatment. (ecb.europa.eu)