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AP Macroeconomics · Unit 4 of 6

Financial Sector

18–23% of the exam9 lessons · 125 min57 terms
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What this unit covers

The topics below follow the published Macro course framework for Unit 4. This unit is worth 18–23% of the exam, so budget your time against that rather than against how long the unit takes to teach.

MoneyBankingMonetary policyMoney market

Lessons in this unit

Formulas in Unit 4

Real vs. nominal interest rate (Fisher)
Real interest rate ≈ Nominal interest rate − Expected inflation rate
The money market sets the nominal rate; borrowers and lenders care about the real rate. Rearranged: nominal rate = real rate + expected inflation.
Money multiplier & maximum money creation
Money multiplier = 1 / RR · Max Δ money supply = Excess reserves × (1 / RR)
RR is the required reserve ratio as a decimal. From a new deposit, excess reserves = deposit × (1 − RR); the required portion is deposit × RR.
The monetary transmission chain (expansionary)
Buy bonds → MS ↑ → interest rate ↓ → investment ↑ → AD ↑ → real GDP ↑, unemployment ↓
Reverse every arrow for contractionary policy (sell bonds → MS ↓ → interest rate ↑ → investment ↓ → AD ↓).
Bond yield
yield ≈ annual payment / price → price and yield move in OPPOSITE directions
The payment is fixed by contract. The only way the yield can change is for the price to move, which is the whole mechanism.
Reserve arithmetic
required reserves = reserve ratio × demand deposits · excess reserves = total reserves − required reserves · max new loans = excess reserves
A bank can lend out its excess reserves only. Required reserves must stay put.
Axes and shifters
vertical: REAL interest rate · horizontal: quantity of loanable funds · supply shifts: private saving, government surplus, foreign capital inflows · demand shifts: investment demand, government borrowing
The real rate, not the nominal rate. This is the first thing that distinguishes this graph from the money market.
The discriminator
Fed action, money supply, nominal rate → MONEY MARKET · deficit, saving, investment, growth, real rate → LOANABLE FUNDS
Read the question for the actor. The central bank lives in one graph, the government budget in the other.
Direction of each tool
EXPANSIONARY: buy bonds · lower discount rate · lower interest on reserves · lower reserve requirement · CONTRACTIONARY: the reverse of each
All four work on the same variable — the quantity of reserves banks want to lend — and therefore on the policy rate.
The transmission chain
buy bonds → MS ↑ → nominal rate ↓ → I and C ↑ (and currency depreciates → Xn ↑) → AD right → real GDP ↑, price level ↑, unemployment ↓
Write the arrows. Free-response rubrics award individual links, so a partial chain still earns partial credit.

Every term in Unit 4

All 57 terms we publish for Financial Sector, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.

Money multiplier
1 / required reserve ratio. Maximum change in the money supply = excess reserves × money multiplier.
Quantity theory of money
MV = PY. In growth rates, %ΔM + %ΔV = %ΔP + %ΔY. With velocity roughly constant, sustained money growth in excess of real output growth produces inflation — the basis for the claim that inflation is ultimately a monetary phenomenon.
Functions of money
Medium of exchange, unit of account, store of value. A question asking "why is X not money" is asking which function fails.
Commodity vs fiat money
Commodity money has intrinsic value (gold); fiat money has value only by government declaration and public confidence. All modern currency is fiat.
Liquidity
How easily an asset converts to cash without loss of value. The ordering principle behind the money supply measures.
M1
The narrowest measure: currency in circulation, checkable deposits, and traveler's checks. Currency sitting in bank vaults is excluded — it is not in circulation.
M2
M1 plus savings deposits, small time deposits and retail money-market funds. Broader and less liquid than M1.
Where savings deposits sit — and why sources disagree
Classic textbook treatment, and most AP material, puts savings deposits in M2 only. In May 2020 the Federal Reserve moved them into M1, because transfers out of savings had become instant. Learn the textbook version for the exam, and know the change exists so a real Fed chart does not confuse you.
Financial asset vs money
Stocks and bonds are stores of value but not media of exchange, so they are not money. Buying a bond changes the composition of your wealth, not the money supply.
Bond
A debt instrument: the issuer borrows and promises fixed payments. Bond prices and interest rates move in opposite directions — the single most tested relationship in this unit.
Why bond prices and interest rates move inversely
A bond's coupon payment is fixed. If market rates rise, the only way an old bond competes is for its price to fall until its yield matches.
Fractional reserve banking
Banks keep a fraction of deposits as reserves and lend the rest. Lending creates new checkable deposits, which is how commercial banks expand the money supply.
Required reserves
The portion of deposits a bank must hold rather than lend, set by the reserve requirement. Required reserves = deposits × required reserve ratio.
Excess reserves
Reserves held beyond the requirement. These are what a bank can lend, and the starting point for every money-creation calculation.
Why actual money creation falls short of the maximum
Banks hold excess reserves voluntarily and the public holds some loans as cash rather than redepositing. Both leakages shrink the effective multiplier.
T-account
A bank balance sheet: assets (reserves, loans, securities) on the left, liabilities and net worth (deposits, owner's equity) on the right. Both sides must change by the same amount.
Money demand curve
Quantity of money people wish to hold at each nominal interest rate. Downward-sloping because the interest rate is the opportunity cost of holding money.
Shifters of money demand
The price level, real GDP, and technology or institutions that change how much cash transactions require. Not the interest rate, which is a movement along.
Money supply curve
Vertical, because the central bank sets the quantity independently of the interest rate. Its position is the policy variable.
Money market equilibrium
Where money demand crosses money supply, determining the nominal interest rate. Adding money shifts MS right and lowers the rate.
The Federal Reserve
The central bank of the United States. Conducts monetary policy, supervises banks, and acts as lender of last resort. Independent of Congress by design.
Dual mandate
Price stability and maximum sustainable employment. When they conflict — as in stagflation — the Fed must choose, and the exam expects you to say why the choice is hard.
Open market operations
The Fed buying or selling government bonds. Buying bonds injects reserves and lowers rates; selling bonds drains reserves and raises them.
Discount rate
The rate the Fed charges banks borrowing directly from it. Lowering it makes reserves cheaper and is expansionary.
Reserve requirement
The fraction of deposits banks must hold. Lowering it frees reserves for lending and raises the money multiplier — a blunt tool, rarely used.
Interest on reserve balances
The rate the Fed pays banks on reserves held at the Fed. Raising it makes holding reserves more attractive than lending, tightening policy without selling assets.
Federal funds rate
The overnight rate banks charge each other for reserves. The Fed's main policy target — it does not set the rate directly but steers it.
Expansionary monetary policy
Buy bonds, lower the discount rate, or lower the reserve requirement. MS shifts right, the nominal rate falls, investment rises, AD shifts right.
Contractionary monetary policy
Sell bonds, raise the discount rate, or raise the reserve requirement. MS shifts left, the nominal rate rises, investment falls, AD shifts left.
The monetary policy transmission chain
Fed buys bonds → reserves rise → MS shifts right → nominal interest rate falls → investment and interest-sensitive consumption rise → AD shifts right → real output and the price level rise. Free-response answers are scored on the links, not the conclusion.
Loanable funds market
Supply is national saving, demand is borrowing for investment, and the price is the real interest rate. Distinct from the money market, whose price is the nominal rate.
Shifters of loanable funds supply
Private saving, public saving (the government budget balance), and capital inflows from abroad. A larger deficit reduces supply and raises the real rate.
Shifters of loanable funds demand
Business investment expectations, government borrowing, and investment tax incentives. Government borrowing shows here as a demand increase in most treatments.
Money market vs loanable funds market
The money market sets the nominal rate and reacts instantly to Fed action. The loanable funds market sets the real rate and is where deficits and saving act. Choose by what the question changes.
Monetary neutrality
In the long run, changes in the money supply change the price level but not real output. The reason LRAS is vertical and the long-run Phillips curve is too.
Liquidity trap
Nominal rates at or near zero, so further money creation cannot lower them and monetary policy loses traction. The standard argument for fiscal policy in a deep recession.
Why bond prices move opposite to rates
The coupon is fixed by contract, so the only way an old bond can compete with higher-paying new ones is for its PRICE to fall. Yield ≈ payment / price.
Liquidity premium
Liquid assets pay less because you are compensated for giving up access. This is why the interest rate is the opportunity cost of holding money.
Liquidity ranking
Cash, then checkable deposits, then savings and money market funds, then bonds and stocks, then real estate. Higher expected return comes with less liquidity or more risk.
Your deposit is the bank's liability
The bank owes it to you. Its assets are the reserves, loans and securities it holds — a distinction that produces most T-account errors.
Required vs excess reserves
Required = ratio × demand deposits. Excess = total − required. A bank can lend only its excess reserves; required reserves must stay put.
How a loan creates money
The bank credits the borrower's deposit account, adding a loan asset and a deposit liability. Since deposits are money, the loan CREATED money.
One bank versus the system
A single bank lends its excess reserves. The system multiplies them by 1/reserve ratio as the money is redeposited elsewhere.
What shrinks the real multiplier
Cash leakage, when people hold currency instead of depositing, and banks choosing to hold excess reserves rather than lend. The formula is a ceiling.
Loanable funds: who supplies, who demands
Supply is national saving plus foreign capital inflows and slopes up. Demand is investment plus government borrowing and slopes down. The price is the REAL rate.
Government borrowing shifts DEMAND
A deficit makes the government a borrower, so loanable funds demand shifts right and the real rate rises. A SURPLUS shifts supply, because it adds to saving.
Money market vs loanable funds: four differences
Nominal vs real rate; vertical vs upward-sloping supply; central bank vs savers and the budget as shifter; monetary policy vs crowding out and growth.
Why money supply is vertical
The quantity of money is a policy variable, not a market response — a higher rate does not cause the Fed to create more. Policy is drawn by MOVING the line.
Why money demand slopes down
The interest rate is the opportunity cost of holding money. High rates make cash expensive to hold, so people economize on it.
What shifts money demand
Nominal income and the price level — more transactions require more money. This is the link from AD–AS back to the money market.
Why open market operations are the routine tool
They can be done in any size, on any day, and reversed the next. No other tool is that finely adjustable.
Federal funds rate vs discount rate
Funds rate: what banks charge EACH OTHER overnight, targeted by the Fed. Discount rate: what the Fed charges banks directly, set above the target as a backstop.
Interest on reserves as a floor
No bank lends to another for less than the risk-free rate it can earn at the Fed. Raising it lifts all short-term rates without selling a single bond.
Why the reserve requirement is not the working tool
It is too blunt — a small change swings the money supply by a large multiple, and it cannot be fine-tuned. The United States cut it to zero in 2020.
The monetary transmission chain
Buy bonds → reserves up → MS right → nominal rate down → investment and interest-sensitive C up, currency depreciates so Xn up → AD right.
Zero lower bound
With rates near zero there is little room to cut, so additional money is held rather than spent. The transmission channel closes.
Why monetary and fiscal lags differ
Monetary policy has almost no legislative lag but a long impact lag. Fiscal policy is the reverse. Slow in different places, not simply slower.

What examiners penalize here

Practice Macro

Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.

84 practice questionsEvery one with a written explanationFRQ trainerWritten answers scored against the rubricMacro study guideAll units, weights and score data in one placeAll 6 Macro unitsThe full course

Questions about this unit

How much of the AP Macroeconomics exam is Unit 4?

Unit 4, Financial Sector, is worth 18–23% of the Macro multiple-choice section according to the published course framework. Across all 6 units that makes it one of the heaviest units on the exam, and worth front-loading.

What topics are covered in Macro Unit 4?

Financial Sector covers Money, Banking, Monetary policy and Money market. We publish 57 terms with definitions for this unit, all of them on this page.

How should I study Macro Unit 4?

Read the 9 lessons below first — about 125 minutes — then drill the 57 terms in cram mode until you can produce each definition from memory rather than just recognize it. Recognition is what makes a unit feel finished when it is not. Finish with practice questions and read the explanation for every one you get right by elimination as well as the ones you miss.

All 6 units of AP Macroeconomics

  1. Unit 1 · Basic Economic Concepts
  2. Unit 2 · Economic Indicators & Business Cycle
  3. Unit 3 · National Income & Price Determination
  4. Unit 4 · Financial Sector
  5. Unit 5 · Long-Run Consequences of Policy
  6. Unit 6 · Open Economy

Unit names, topics and exam weights follow the published College Board course framework for AP Macroeconomics. AP® is a trademark registered by the College Board, which does not endorse this site.