Money, the Federal Reserve, and Interest Rates

Money is one of humanity's most useful inventions, yet it is easy to misunderstand. Money is not the same as wealth or income, and most of it is not physical currency at all. This chapter explains what money is and what it does, how the banking system actually creates most of it, and how the Federal Reserve — the central bank — oversees the whole system and influences interest rates.

The Functions of Money

Anything that serves three functions can be money:

• Medium of exchange — Money is accepted in trade, eliminating the need for barter and the awkward "double coincidence of wants" it requires.
• Unit of account — Money provides a common yardstick for quoting prices and keeping accounts.
• Store of value — Money holds purchasing power over time, letting people save and spend later (though inflation erodes this function).

Money has value not because it is backed by gold but because it is generally accepted and relatively scarce — what economists call fiat money.

Measuring the Money Supply

Because "money" includes more than cash, economists use several measures. M1 is the narrowest: currency in circulation plus checkable deposits and other very liquid funds — money usable for spending almost immediately. M2 is broader, adding savings deposits, small time deposits, and money market funds — assets that are slightly less liquid but easily converted to spendable money. These measures matter because the quantity of money in the economy affects spending, interest rates, and prices.

Banks and the Creation of Money

A striking fact about modern economies is that most money is created not by the government printing currency but by commercial banks making loans. This happens through fractional reserve banking.

Banks keep only a fraction of their deposits on hand as reserves and lend out the rest. When a bank makes a loan, it credits the borrower's account, creating a new deposit — and that deposit is money. The borrower spends it, the recipient deposits it in another bank, which keeps a fraction and lends the rest, and so on. Through this process the banking system as a whole can expand the money supply by a multiple of the original reserves. The maximum expansion is governed by the money multiplier, the inverse of the reserve ratio. The same process can run in reverse, contracting the money supply when loans are repaid or reserves shrink.

The Federal Reserve System

Overseeing this system in the United States is the Federal Reserve ("the Fed"), the nation's central bank. It is structured as a Board of Governors in Washington together with twelve regional Reserve Banks, and its policy-making body for interest rates is the Federal Open Market Committee. The Fed is designed to be relatively independent of day-to-day politics so that it can take a long-run view.

The Fed's main responsibilities include conducting monetary policy, serving as a "lender of last resort" to banks during crises, supervising and regulating banks, and maintaining the payments system. Its statutory goals — its dual mandate — are maximum employment and stable prices.

Money and Interest Rates

In the short run, the Fed influences interest rates through the supply of money. The interest rate can be thought of as the price of holding money or, equivalently, the reward for lending it. When the Fed increases the money supply, interest rates tend to fall; when it reduces the money supply, rates tend to rise. Because investment and many forms of consumer spending are sensitive to interest rates, this link is the channel through which monetary policy reaches the broader economy.

A Note on Cryptocurrency

Digital currencies such as Bitcoin have prompted fresh debate about the nature of money. They can function as a store of value or speculative asset, but their high volatility and limited acceptance have so far constrained their use as a medium of exchange or unit of account. Evaluating them against money's three classic functions is a useful way to cut through the hype.

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Next chapter: with the monetary system in place, we examine how the Fed uses it to influence GDP and the price level — the conduct of monetary policy.

Further Listening & Reading

• 🎥 The U.S. Money Supplies (MRU) — what counts as money (M1 and M2).
• 🎥 The Money Multiplier (MRU) — how fractional-reserve banking creates money.
• 🎧 This American Life #423: The Invention of Money — what money even is, and a tour of "Fed Crazytown."
• 🎧 Planet Money #505: The Birth of the Fed (NPR) — the origin story of the central bank.