Money Creation — AP Macroeconomics
1. What Is Money Creation? ★★☆☆☆ ⏱ 2 min
Money creation (also called multiple deposit creation or money supply expansion) is the process by which the commercial banking system expands the overall money supply beyond the initial amount of base money injected by the central bank. This process relies entirely on fractional reserve banking, the standard system operating in all modern economies.
A common misconception is that money creation is only the central bank "printing money": in reality, most of the broad money supply (M1/M2) in modern economies is created by commercial banks through lending, not by the central bank directly.
2. Fractional Reserve Banking and Reserve Requirements ★★☆☆☆ ⏱ 3 min
Fractional reserve banking is the core institutional arrangement that enables money creation. Under this system, central banks require commercial banks to hold a fixed fraction of their deposits as reserves (vault cash plus deposits held at the central bank).
The portion of deposits that banks hold above the required amount is called excess reserves ($ER$), which banks can lend out to borrowers. When a bank makes a loan, it credits the borrower’s checking account, increasing total checkable deposits (and thus M1) immediately. The loan is spent, the recipient deposits the funds into another bank, which keeps the required amount in reserves and lends out the rest. This repeated cycle expands the total money supply multiple times over the initial reserve injection.
Required reserves are calculated as:
RR = rr \times D
where $D$ is total checkable deposits. Excess reserves are calculated as:
ER = \text{Total Reserves} - RR
Exam tip: Always confirm whether the deposit is new to the entire banking system or just a transfer between banks—only new deposits increase total reserves and enable new money creation.
3. The Money Multiplier (Simple and Adjusted) ★★★☆☆ ⏱ 4 min
The money multiplier measures how much the total money supply increases for every \$1 of new reserves injected into the banking system. The simple money multiplier assumes two key conditions: (1) banks lend out all excess reserves (so $e = 0$, no excess reserves held) and (2) the public holds no currency (so $c = 0$, all loan proceeds are re-deposited into banks). Under these assumptions, the simple money multiplier is:
mm_s = \frac{1}{rr}
In the real world, leakages exist: banks often hold excess reserves for liquidity, and the public holds some currency for transactions instead of depositing all funds. Both leakages reduce the amount of money that can be re-lent at each step of the cycle, so the actual (adjusted) money multiplier is smaller than the simple multiplier. The adjusted formula for the money multiplier is:
mm_a = \frac{1 + c}{rr + c + e}
The total change in the money supply is always $\Delta M_s = \Delta R \times mm$, where $\Delta R$ is the change in total reserves.
Exam tip: On FRQs, you must explicitly state your assumptions (e.g., "no excess reserves, no currency leakage") when using the simple multiplier to earn full points.
4. Bank Balance Sheets and Money Creation ★★★☆☆ ⏱ 3 min
Money creation can be clearly tracked through commercial bank balance sheets, which follow the fundamental accounting identity:
\text{Total Assets} = \text{Total Liabilities} + \text{Net Worth}
- **Liabilities**: Customer checkable deposits are the primary liability, because the bank owes this money to depositors.
- **Assets**: Required reserves, excess reserves, loans, and securities (like government bonds) are all assets, because they represent value the bank owns or is owed by others.
When a new deposit is made, liabilities increase by the deposit amount, and assets increase by the same amount split between required and excess reserves. When the bank lends out excess reserves, excess reserves fall, and loans rise by the same amount (keeping total assets equal to liabilities), while the new loan creates a new deposit, increasing the money supply.
Exam tip: AP graders always check that balance sheets are balanced—if your total assets do not equal total liabilities, you will lose points even if your individual numbers are correct.
5. AP-Style Concept Check ★★★☆☆ ⏱ 2 min
Common Pitfalls
Why: Students memorize that commercial banks create "new money" equal to total deposits minus the initial injection, so they subtract it by default.
Why: The simple multiplier is easier to calculate, so students default to it even when leakages are explicitly given.
Why: Students confuse "loans the bank has issued" with "money the bank owes", thinking loans are liabilities.
Why: Popular media conflates base money creation with broad money creation.
Why: Students mix up the relationship between reserve requirements and the multiplier.
Why: Students assume any new deposit to a single bank is new to the whole system.