15.1 Show Me the Money

The Basics of Money

Characteristics and Functions

Money does three things in an economy, and understanding these functions helps explain why we use it instead of, say, trading chickens for haircuts.

Three functions of money:

• Medium of exchange — Money lets buyers and sellers complete transactions without bartering. Bartering means directly swapping goods or services, which only works if both people want what the other has. Money eliminates that problem.
• Unit of account — Money gives us a standard way to measure value. Instead of figuring out how many loaves of bread equal a pair of shoes, everything gets a price tag in the same unit (dollars, euros, yen).
• Store of value — Money holds its purchasing power over time, so you can earn it today and spend it next month. This is what makes saving possible.

For something to work well as money, it needs six characteristics:

• Durability — It has to survive being handled constantly. Coins last decades; paper bills are reinforced to resist tearing.
• Portability — It needs to be lightweight and compact enough to carry around easily.
• Divisibility — You need to be able to break it into smaller units for exact payments. That's why we have cents, not just whole dollars.
• Uniformity — Every dollar bill needs to be worth the same as every other dollar bill. Standardized features like serial numbers and watermarks help with this.
• Limited supply — If you could create unlimited amounts of it, it would lose its value. Scarcity is what keeps money worth something and helps prevent inflation.
• Acceptability — Everyone in the economy has to recognize it and trust it as payment. Money only works if people believe it works.

Components of the U.S. Money Supply

M1, M2, and M3

The Federal Reserve categorizes the money supply into layers based on how quickly and easily each type of money can be spent. Think of it like rings: M1 is the most liquid (easiest to spend), and each layer outward adds less liquid forms.

M1 — the most liquid money:

• Currency in circulation — Physical cash (banknotes and coins) held by the public
• Demand deposits — Checking accounts at banks that you can withdraw from at any time
• Other checkable deposits — Accounts like NOW (Negotiable Order of Withdrawal) accounts that allow unlimited check-writing while sometimes earning interest

M2 — M1 plus near-money:

M2 includes everything in M1, plus forms of money that take a small extra step to spend:

• Savings deposits — Accounts that earn interest but historically have had limited withdrawals
• Small time deposits — Certificates of deposit (CDs) under $100,000, where you lock your money away for a set period in exchange for a higher interest rate
• Money market mutual funds — Funds that invest in short-term, low-risk securities like Treasury bills and commercial paper

M3 — M2 plus large institutional money:

The Federal Reserve stopped publishing M3 data in 2006, but the category included everything in M2 plus:

• Large time deposits — CDs of $100,000 or more
• Institutional money market funds — Money market funds used by large organizations and financial institutions
• Repurchase agreements (repos) — Short-term loans backed by U.S. government securities

Factors Influencing Currency Circulation

Demand, Income, and Alternatives

Several forces determine how much money is actively moving through the economy at any given time.

Consumer demand — When people want to buy more goods and services, more currency circulates. Economic growth and high consumer confidence (tracked by measures like the consumer sentiment index) drive spending up.

Income levels — As incomes rise, people spend more. Higher-income individuals also tend to shift toward electronic payments like credit cards and mobile apps, which means more money moves digitally rather than as physical cash.

Alternative payment methods are steadily reducing the role of physical cash:

• Credit and debit cards handle a growing share of everyday transactions
• Mobile payment apps like Venmo and PayPal enable instant digital transfers
• Cryptocurrencies like Bitcoin and Ethereum represent decentralized digital currencies that operate outside traditional banking systems

Monetary policy from the Federal Reserve directly shapes how much money is in circulation:

1. Interest rates — Lower rates make borrowing cheaper, which encourages spending and puts more money into the economy. Higher rates do the opposite.
2. Open market operations — When the Fed buys government securities, it injects money into the economy. When it sells them, it pulls money out.

Seasonal factors also play a role. Holiday shopping seasons (think Black Friday and Christmas) cause noticeable spikes in currency circulation, and summer travel and tourism tend to boost cash transactions as well.