Money and Banking
The Functions of Money
Money exists because a barter economy, in which people trade goods and services directly for other goods and services, runs into a fundamental problem: it requires a double coincidence of wants, meaning each party must happen to want exactly what the other person is offering. An accountant who wants shoes must find a shoemaker who happens to need accounting services at that exact moment, which is a demanding coincidence to rely on for every transaction in an economy. Money solves this problem by serving three core functions. First, it acts as a medium of exchange, letting the accountant sell accounting services for money and then use that money to buy shoes from anyone, without needing the shoemaker to want accounting services specifically. Second, it serves as a store of value, letting someone hold wealth in a form that does not spoil, go out of style, or otherwise lose usefulness while waiting to be spent. Third, it serves as a unit of account, giving the economy a common measure for comparing the prices of very different goods and services, such as a haircut against a bicycle repair, without needing to negotiate a direct exchange rate between every possible pair of goods.
From Commodity Money to Fiat Money
Early forms of money were often commodity money, meaning the money itself had value independent of its use as money, such as gold or silver coins that could also be melted down and used as metal. Commodity-backed money followed, in which paper currency represented a promise to redeem it for a fixed quantity of some commodity, such as a bill that could once be exchanged for a set amount of gold or silver held by a government. Most modern economies have since moved to fiat money, currency that has no intrinsic value as a commodity but is declared legal tender by government decree, meaning it must be accepted for debts and transactions within that country. Fiat money’s value ultimately rests entirely on widespread trust that other people will continue to accept it in exchange for real goods and services, rather than on any underlying commodity backing it, which is why maintaining that trust is a central concern for the institutions that manage a country’s money supply.
Measuring the Money Supply: M1 and M2
Economists measure the money supply using categories organized by liquidity, meaning how quickly and easily an asset can be converted into spendable cash without losing value. M1, the narrowest commonly used measure, includes currency in circulation and funds held in checking accounts, since both can be spent almost immediately. M2, a broader measure, includes everything in M1 plus assets that are still fairly liquid but take a bit more effort to access, such as savings accounts, small-denomination time deposits like certificates of deposit, and retail money market fund balances. The distinction matters for policy purposes because M1 captures money that is readily available for immediate spending, while M2 captures a wider pool of household savings that could be converted into spendable funds relatively quickly if needed, and central banks track both measures to understand how much spending power exists in an economy at a given time.
Banks as Financial Intermediaries
Banks act as financial intermediaries, standing between savers who want a safe place to deposit funds and earn some return, and borrowers who need funds to buy a home, expand a business, or cover a large purchase. A saver deposits funds into a bank account and earns interest, while a borrower takes out a loan from the bank and repays it with interest over time, with the bank profiting from the difference between the interest it pays depositors and the interest it charges borrowers. This intermediation role is valuable because an individual saver rarely has the time, expertise, or risk tolerance to evaluate and lend directly to individual borrowers, while a bank can pool many small deposits together, spread lending risk across many borrowers, and specialize in assessing creditworthiness, making the overall system of channeling savings toward productive borrowing far more efficient than savers and borrowers trying to find each other directly.
Bank Balance Sheets and T-Accounts
A bank’s financial position can be summarized using a T-account, a simplified balance sheet with assets listed on one side and liabilities on the other. A bank’s assets include its reserves, meaning cash it holds rather than lends out, along with the loans it has made to customers and any bonds it holds, since these represent money owed to the bank. A bank’s liabilities are primarily the deposits customers have placed with it, since the bank owes that money back to depositors on request. The bank’s net worth equals its total assets minus its total liabilities; a financially healthy bank has positive net worth, while a bank whose assets have fallen in value, perhaps because too many borrowers defaulted on loans at once, can end up with negative net worth, meaning it would be unable to repay all its depositors in full if they tried to withdraw their funds at the same time, which is the basic mechanism behind a bank becoming insolvent.
How Banks Create Money: The Money Multiplier
Banks do not simply store deposits; the banking system as a whole actually creates money through the process of making loans, because a regulator typically requires banks to hold only a fraction of deposits as reserves and lend out the rest. Suppose a regional bank receives a ten-million-dollar deposit and must hold ten percent, one million dollars, as required reserves, lending out the remaining nine million dollars, perhaps as a loan to a hardware store owner expanding her shop. If that nine million dollars is deposited into another bank, that bank in turn holds ten percent as reserves and lends out the remaining ninety percent, and this process repeats across the banking system, with each round of lending adding to the total money supply. The money multiplier formula captures the cumulative effect of this process: it equals one divided by the reserve requirement, so with a ten percent reserve requirement, the multiplier is ten, meaning the original nine million dollars in excess reserves can ultimately expand the money supply by up to ninety million dollars across the full banking system, assuming banks lend out all their excess reserves at each stage.
Quick Revision Summary
Money solves the double-coincidence-of-wants problem inherent in barter by serving as a medium of exchange, a store of value, and a unit of account. Economies have moved historically from commodity money, which has independent value, through commodity-backed paper money, to fiat money, whose value rests entirely on trust and government decree rather than any underlying commodity. M1 measures the most liquid forms of money, currency and checking deposits, while the broader M2 measure adds savings accounts, time deposits, and money market funds. Banks act as financial intermediaries, channeling funds from savers to borrowers and profiting from the spread between deposit and loan interest rates, a role their balance sheets summarize through T-accounts showing assets, liabilities, and net worth. Because banks hold only a fraction of deposits as reserves and lend out the rest, the banking system as a whole creates money through repeated rounds of lending, an effect captured by the money multiplier, equal to one divided by the reserve requirement.