Measures of Money Supply
AP MacroeconomicsΒ· AP Macroeconomics CED β Financial SectorΒ· 14 min read
1. Core Concepts of Monetary Aggregatesβ β ββββ± 3 min
Measures of money supply are standardized hierarchical classifications of the total amount of money held by the non-bank public in an economy at a given point in time. Central banks create these measures to track liquidity, set monetary policy, and report overall economic conditions.
For the AP Macroeconomics exam, you only need to master two core aggregates: narrow money (M1) and broad money (M2). Broader aggregates like M3 or MZM are not tested on the current Course and Exam Description (CED), so you can ignore them for the exam. Aggregates are grouped by liquidity, with more liquid assets falling into narrower aggregates.
2. M1: Narrow Moneyβ β ββββ± 4 min
M1 is the narrowest measure of money supply, designed to capture only the most liquid assets that can be immediately used as a medium of exchange for everyday transactions. By definition, M1 only includes assets that require no conversion to spend directly.
M1 (Narrow Money)
The narrowest monetary aggregate, including only the most liquid transaction assets held by the non-bank public. Excludes currency held by banks and non-public deposits.
Example:
Currency in your wallet, balances in your checking account
Currency in circulation excludes physical currency held in commercial bank vaults or at the central bank, because this currency is not held by the public, and is already implicitly counted in customer deposit balances. Counting vault cash would lead to double-counting the same money.
A central bank publishes the following values for its economy (all in billions of dollars): Currency in commercial bank vaults = 120, Currency held by households and firms = 450, Demand deposits = 1100, Savings deposits = 800, Traveler's checks outstanding = 10. Calculate M1 for this economy.
- 1
First, separate eligible M1 components from ineligible ones. Currency in vaults is not part of currency in circulation, so we exclude it. Savings deposits are not checkable transaction accounts, so we also exclude them.
- 2
List eligible components: Currency held by the public (currency in circulation) = 450, demand deposits = 1100, traveler's checks = 10.
- 3
Sum the eligible components to get M1:
- 4
- 5
Confirm no double-counting: We correctly excluded bank-held currency, so no overcounting occurred.
Exam tip:
On AP MCQ questions asking for M1, always cross out 'vault cash' or 'currency in bank vaults' immediately β this is the most common distractor used in these problems.
3. M2: Broad Moneyβ β β βββ± 4 min
M2 is the broader measure of money supply that includes all of M1 plus less liquid 'near-money' assets. Near-money assets cannot be used directly for transactions, but can be converted to M1 (cash or checking) quickly with little to no loss of value, so they count as part of the overall money supply.
M2 (Broad Money)
The broad monetary aggregate tested on AP Macroeconomics, which includes all components of M1 plus eligible near-money assets.
Example:
Savings account balances, small certificates of deposit, retail money market funds
M2 is the most commonly tracked measure of money supply by policymakers because it better reflects overall liquidity in the economy and is a more reliable predictor of future inflation than M1 alone. For the AP exam, you are expected to both calculate M2 from given components and classify assets into the correct aggregate.
Using the M1 calculation from the previous example, add the following additional values (all in billions of dollars): Savings deposits = 800, Small time deposits = 350, Retail money market mutual funds = 220, Large time deposits = 400. Calculate M2 for this economy.
- 1
We start with the pre-calculated M1 value of 1560 billion, since M2 always includes all components of M1.
- 2
Separate eligible near-money assets from ineligible ones: Include savings deposits (800), small time deposits (350), and retail money market mutual funds (220). Exclude large time deposits, which are not part of M2 per the AP definition.
- 3
Add the eligible near-money assets to M1:
- 4
- 5
Confirm the hierarchy: We did not subtract any M1 components, which follows the rule that all M1 is included in M2.
Exam tip:
If a question asks whether a given M1 asset is part of M2, the answer is always yes β all M1 assets are included in M2, no exceptions.
4. Liquidity Hierarchy and Asset Classificationβ β β βββ± 4 min
Monetary aggregates are structured as a hierarchy based on liquidity, so there are clear rules for comparing their liquidity and total size. Because narrower aggregates only include the most liquid assets, the order of liquidity is inverse to the order of total size.
This hierarchy reflects the difference between money for immediate spending (M1) and money held as a store of value that can be converted to spending money quickly (M2). For the AP exam, classifying assets correctly is just as important as calculating aggregates.
Classify each of the following assets as (i) both M1 and M2, (ii) M2 only, or (iii) neither M1 nor M2: (a) A $100 bill in your wallet, (b) A $5,000 balance in your personal savings account, (c) A $2,000 balance in your checking account, (d) A $10,000 small-denomination certificate of deposit, (e) A $10,000 share of public company stock.
- 1
First, recall the core hierarchy rule: All M1 assets are automatically part of M2, so no asset is M1 only.
- 2
Classify each asset: (a) A $100 bill in your wallet is currency in circulation, part of M1 β so it is both M1 and M2. (b) A $5,000 savings account balance is a near-money asset β so it is M2 only. (c) A $2,000 checking account balance is a demand deposit, part of M1 β so it is both M1 and M2. (d) A $10,000 small CD is a near-money asset, part of M2 but not M1 β so it is M2 only. (e) A share of stock is not money (it cannot be converted to cash quickly without price risk) β so it is neither.
- 3
Confirm against the hierarchy rule: We did not classify any asset as M1 only, which aligns with the hierarchical structure.
Test your understanding with these AP-style questions:
Use the table below for an economy, all values in billions of USD:
Asset Value Currency held by public 320 Vault cash 80 Demand deposits 780 Savings deposits 950 Small time deposits 210 Retail money market mutual funds 140 What is the value of M1 and M2 for this economy?
A) M1 = $1100 billion, M2 = $2400 billion
B) M1 = $1180 billion, M2 = $2480 billion
C) M1 = $1100 billion, M2 = $2320 billion
D) M1 = $400 billion, M2 = $2100 billion
An economy has the following monetary asset values: Currency in circulation: 250, Demand deposits: 600, Savings deposits: 720, Large time deposits: 500, Retail money market mutual funds: 180, Small time deposits: 100. A household converts $100 million from their savings account to their checking account. What happens to M1 and M2?
M1 increases, M2 increases
M1 increases, M2 stays the same
M1 stays the same, M2 increases
M1 stays the same, M2 stays the same
Reveal answer
1 βCorrect! Moving money from savings (not M1, but included in M2) to checking (included in both M1 and M2) adds to M1 but leaves total M2 unchanged.
Exam tip:
If a multiple-choice option includes the label 'M1 only', that option is almost always wrong β only select it if the question explicitly asks to separate M1 from M2, which is extremely rare on the AP exam.
5. Common Pitfalls
Wrong move:
Counting currency held in bank vaults as part of currency in circulation for M1
Why:
Students assume all physical currency is counted, but vault cash is held by banks, not the public, and is already counted in customer deposit balances.
Correct move:
Always cross out 'vault cash' or 'currency in bank vaults' before adding components for any money supply calculation.
Wrong move:
Calculating M2 as only the sum of near-money assets, instead of starting from M1
Why:
Students confuse the hierarchical structure, thinking M1 and M2 are separate mutually exclusive groups.
Correct move:
Always calculate M1 first, then add near-money assets to M1 to get M2.
Wrong move:
Classifying a M1 asset as 'M1 only' on a classification question
Why:
Students forget that all narrower aggregates are included in broader aggregates, so they treat M1 and M2 as separate groups.
Correct move:
Before answering any classification question, remind yourself 'all M1 is M2', so M1 assets are always in both aggregates.
Wrong move:
Counting large time deposits, stocks, or government bonds as part of M2
Why:
Students assume all financial assets are part of the money supply, but only small retail near-money assets are included in M2 per the AP definition.
Correct move:
Exclude all large time deposits, stocks, bonds, and other non-money financial assets from M1 and M2 calculations.
Wrong move:
Claiming M2 is more liquid than M1 because it has a larger total value
Why:
Students confuse total size (sum of all assets) with liquidity (ease of spending the asset).
Correct move:
Memorize the fixed order: liquidity = , total size = , never reverse these.
Wrong move:
Counting deposits held by the government or central bank as part of M1
Why:
Students forget that money supply only counts money held by the non-bank public.
Correct move:
Exclude all deposits held by the government or central bank from any money supply calculation.
6. Quick Reference Cheatsheet
Category | Formula / Rule | Notes |
|---|---|---|
M1 (Narrow Money) | Excludes vault cash and government/central bank deposits; only includes most liquid transaction assets. | |
M2 (Broad Money) | All M1 assets are included in M2; excludes large time deposits, stocks, and bonds. | |
Liquidity Order | Narrow money can be spent immediately, while M2 adds less liquid near-money assets. | |
Total Size Order | M2 always includes all M1 plus additional assets, so it is always larger. | |
M1 Asset Classification | All M1 assets = Both M1 and M2 | No M1 asset is excluded from M2, so 'M1 only' is almost always wrong. |
Near-Money Asset Classification | Near-money assets = M2 only | These are not liquid enough for M1, but are liquid enough for M2. |
Non-Money Asset Classification | Non-money assets = Neither M1 nor M2 | Vault cash, large time deposits, stocks, bonds, and government deposits fall into this category. |
When this came up on past exams
AI-estimated based on syllabus patterns β cross-check with official past papers for accuracy. Use only as revision-focus signals.
- 2023 Β· MCQ
Calculate M1 from given asset values
- 2022 Β· FRQ
Classify assets into M1/M2 aggregates
Going deeper
What's Next
Mastering measures of money supply is the foundational prerequisite for the next core topics in Unit 4: the money creation process by commercial banks and the role of the money multiplier. You cannot correctly calculate the change in the money supply from open market operations or reserve requirement changes if you do not understand what counts as money in the first place. Beyond Unit 4, measures of money supply are a core input for analyzing monetary policy, inflation, and aggregate demand in later units, as changes in money supply directly impact interest rates and macroeconomic output.