DP Economics HL 3.6 Demand Management: Monetary Policy

DP Economics HL 3.6 Demand Management: Monetary Policy - Full notes

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DP Economics HL | 3.6 Demand Management: Monetary Policy

DP ECONOMICS · UNIT 3: MACROECONOMICS

3.6

Demand Management: Monetary Policy

Full notes for HL · IB-style

Contents

1	Central banks and the goals of monetary policy
2	Interest rates and the money market
3	The tools of monetary policy
4	The transmission mechanism
5	Expansionary and contractionary monetary policy
6	Inflation targeting and central bank independence
7	Strengths and limitations of monetary policy
8	Money creation by commercial banks (HL only)
9	The role of the central bank
10	Inflation targeting
11	How interest rates affect AD
12	Expansionary monetary policy
13	Contractionary monetary policy
14	Tools of monetary policy
15	Quantitative easing
16	Real interest rates
17	Evaluating monetary policy
18	Monetary policy and exchange rates
19	Demand and supply of money (HL)
20	Commercial banks and money creation (HL)
21	Mixed review: worked problems
22	Additional exam-style practice
23	Monetary policy and cost-push inflation
24	Distributional effects of monetary policy
25	Common misconceptions and links
26	Exam-style question with markscheme
27	Check your understanding
28	Summary and topic map

These are full teaching notes. Read each section in order, try the Think about it question before you read on, and do every Quick check before moving to the next section.

Before you start

Rate yourself on each statement now, and again after you've worked through the notes. Shade R (not yet), A (getting there) or G (confident).

I can…	R	A	G
explain the role and goals of a central bank
explain how the interest rate is determined in the money market
explain open market operations, reserve requirements, the policy rate and quantitative easing
explain the transmission mechanism from interest rates to AD
use AD/AS to analyse expansionary and contractionary monetary policy
explain inflation targeting and the role of independence
evaluate monetary policy, including time lags and the zero lower bound
explain how commercial banks create money and calculate the money multiplier

Section 8 (money creation) is Additional Higher Level content. Every other section is common to SL and HL.

Guiding questions

Why do central banks raise interest rates when inflation rises? How does a change in one interest rate affect the whole economy? What can a central bank do when interest rates are already near zero?

How this topic is examined

Monetary policy is examined together with fiscal and supply-side policy. Paper 1 essays often ask you to compare the effectiveness of monetary and fiscal policy in a recession or in fighting inflation.

Paper 2 texts frequently report central bank decisions and inflation data. You must be able to trace the transmission mechanism step by step and evaluate it with time lags and the limits of rate cuts. Paper 3 may ask for money multiplier calculations.

Command term	What the examiner wants
Define	the precise meaning, ideally in the IB wording, in one or two sentences
Draw / Sketch	a fully labelled diagram with every axis, curve, equilibrium and change labelled
Explain	a causal chain linked to economic theory, usually supported by a diagram
Analyse	break a situation into its parts and trace the effects of each
Evaluate / Discuss	weigh up arguments, question assumptions and reach a justified conclusion using real-world examples
Calculate	calculate the money multiplier and the change in money supply step by step

How to use these notes

Each section teaches one part of the syllabus in full. You'll see these boxes throughout; each has one job:

Box	What it's for
Think about it	a question to get you thinking before a section; the answer comes in the section
Key point	the one idea you must not forget
Common mistake	an error examiners see every year, and how to avoid it
In the real world	where the economics shows up outside the classroom
Try this	something quick you can do yourself to test the idea
Worked example	full solutions with IB-style marks (M1 method, A1 answer, R1 reasoning)
Quick check	short questions to test yourself at the end of each section

1 Central banks and the goals of monetary policy

Monetary policy is about the price and quantity of money.

Think about it

Who decides the interest rate on your family's mortgage or savings account? What sets the level for the whole economy?

Monetary policy is the use of interest rates and the money supply by the central bank to influence aggregate demand and achieve macroeconomic objectives. Examples of central banks are the US Federal Reserve, the European Central Bank, the Bank of England and the Reserve Bank of India.

A central bank has several roles: it is the banker to the government, the banker to commercial banks, the lender of last resort in a crisis, the regulator of the banking system in many countries, and the authority responsible for monetary policy.

The main goal of monetary policy in most countries is low and stable inflation, usually defined as an inflation target such as 2% a year. Many central banks also aim to support employment and growth, and to keep the financial system stable. The US Federal Reserve, for example, has a 'dual mandate' of price stability and maximum employment.

Quick check

1. Define monetary policy.

2. Name three roles of a central bank.

3. What is the main goal of monetary policy?

Answers: 1. use of interest rates and money supply by the central bank to influence AD 2. banker to government and banks, lender of last resort, regulator, monetary policy 3. low and stable inflation

2 Interest rates and the money market

The interest rate is the price of money.

An interest rate is the price of borrowing money, or the reward for saving it, expressed as a percentage per year. The central bank sets a policy rate (also called the base rate, repo rate or minimum lending rate): the rate at which it lends to commercial banks. Changes in this rate pass through to the rates banks charge on loans and pay on deposits.

The interest rate can be shown in a money market diagram. The demand for money slopes downward: at higher interest rates, holding cash is more costly (you lose the interest you could earn), so people hold less money. The supply of money is set by the central bank and is drawn as a vertical line. The equilibrium interest rate is where they meet.

If the central bank increases the money supply, the supply curve shifts right and the interest rate falls. If it reduces the money supply, the interest rate rises.

Figure 1. The money market: an increase in the money supply from Sm to Sm1 lowers the interest rate from r1 to r2.

The real interest rate adjusts the nominal rate for inflation: real interest rate ≈ nominal interest rate − inflation rate. If a bank pays 5% on savings but inflation is 8%, the real return is about −3%: savers lose purchasing power. Real rates matter more for decisions to borrow and save.

WORKED EXAMPLE 1 Real interest rate

The central bank's policy rate is 2.25% and inflation is 8%. Calculate the real interest rate and explain its significance.

Solution

Real rate ≈ 2.25 − 8 = −5.75%A1

A negative real rate means borrowers repay less in real terms than they borrowed: monetary policy is still very looseR1

Quick check

1. Why does the demand for money slope downward?

2. What happens to the interest rate when the money supply increases?

3. Calculate the real rate if the nominal rate is 6% and inflation 2%.

Answers: 1. higher rates raise the opportunity cost of holding money 2. it falls 3. 4%

3 The tools of monetary policy

Central banks have four main tools.

Changing the policy (minimum lending) rate. This is the main tool in most countries. When the central bank raises the rate at which it lends to commercial banks, banks raise the rates they charge customers, and vice versa.

Open market operations (OMO). The central bank buys or sells government bonds in the financial markets. Buying bonds pays money into the banking system, increasing banks' reserves and the money supply, and lowering interest rates. Selling bonds takes money out, reducing the money supply and raising interest rates.

Minimum reserve requirements. Commercial banks must hold a minimum percentage of their deposits as reserves. Raising the requirement reduces the amount banks can lend, reducing the money supply; lowering it increases lending.

Quantitative easing (QE). When interest rates are already close to zero, central banks can buy large quantities of government and other bonds, creating new money. QE lowers long-term interest rates, raises asset prices and increases banks' reserves, encouraging lending and spending. It was used on a huge scale after 2008 and in 2020.

Tool	To increase AD (expansionary)	To reduce AD (contractionary)
Policy rate	cut the rate	raise the rate
Open market operations	buy bonds	sell bonds
Reserve requirements	lower the requirement	raise the requirement
Quantitative easing	buy bonds on a large scale	quantitative tightening: sell or stop replacing bonds

Quick check

1. What does buying bonds do to the money supply?

2. When is QE used?

3. How does a higher reserve requirement affect lending?

Answers: 1. increases it 2. when interest rates are near zero 3. reduces it

4 The transmission mechanism

How a change in the policy rate reaches the whole economy.

The transmission mechanism is the chain of effects through which a change in the policy interest rate influences aggregate demand and inflation. Consider a cut in interest rates:

Consumption rises. Borrowing to buy cars, houses and other goods becomes cheaper; saving becomes less rewarding; households with variable-rate mortgages pay less interest and have more to spend.

Investment rises. Firms can borrow more cheaply to finance new projects, so more projects become profitable.

Asset prices rise. Lower rates raise the prices of houses and shares, making households feel wealthier (the wealth effect) and spend more.

The exchange rate falls. Lower rates make the currency less attractive to foreign savers, so it depreciates; exports become cheaper and imports dearer, so net exports rise.

All of these shift AD to the right, raising output and, if the economy is near capacity, inflation. A rise in interest rates works in the opposite direction.

Figure 2. The transmission mechanism of an interest rate cut.

Common mistake

Saying 'lower interest rates increase saving'. They reduce the reward for saving, so saving tends to fall and spending rises.

Quick check

1. Trace how a rate cut affects investment.

2. How does a rate rise affect the exchange rate and net exports?

Answers: 1. cheaper borrowing makes more projects profitable; I rises 2. currency appreciates; net exports fall

5 Expansionary and contractionary monetary policy

Loosen to fight recession; tighten to fight inflation.

Expansionary (loose) monetary policy, cutting interest rates or increasing the money supply, is used to raise AD in a recession, closing a deflationary gap and reducing cyclical unemployment.

Contractionary (tight) monetary policy, raising interest rates or reducing the money supply, is used to reduce AD when inflation is above target, closing an inflationary gap.

Figure 3. Contractionary monetary policy: higher interest rates shift AD left, reducing inflationary pressure.

In the real world

Between 2022 and 2023, as inflation reached its highest level in about 40 years, the US Federal Reserve raised its policy rate from near 0% to over 5%, and the European Central Bank and Bank of England did the same. Inflation fell back over the following two years, though with a delay.

Quick check

1. When would a central bank use contractionary policy?

2. Name one expansionary monetary tool.

Answers: 1. when inflation is above target 2. cut the policy rate / buy bonds / QE

6 Inflation targeting and central bank independence

Credibility is one of a central bank's most important tools.

Many central banks have an explicit inflation target, often 2%, with some tolerance band. If forecast inflation is above target, they tighten policy; if below, they loosen it. A clear target helps anchor expectations: if people believe inflation will stay near 2%, they set wages and prices accordingly, which makes it easier to keep inflation there.

Most central banks are now independent of government: they set interest rates without political interference. Independence matters because governments have an incentive to cut rates before elections to boost growth, even at the cost of higher inflation later. An independent central bank is more credible in its commitment to low inflation.

Quick check

1. Why do inflation targets help anchor expectations?

2. Why does independence improve credibility?

Answers: 1. people expect inflation near target and set wages and prices accordingly 2. decisions are free from short-term political pressure

7 Strengths and limitations of monetary policy

Flexible and fast to decide, but slow to work and limited at zero.

Strengths	Limitations
can be changed quickly and in small steps	time lags: 18 to 24 months to affect inflation fully
independent of politics, so credible	zero lower bound: rates cannot easily go below zero (liquidity trap)
no direct effect on government debt	weak in deep recessions: low confidence means people won't borrow (‘pushing on a string’)
affects many sectors at once	cannot target specific regions or sectors
effective against demand-pull inflation	ineffective against cost-push inflation; fighting it raises unemployment
	high debt levels make households and firms very sensitive to rate rises

The zero lower bound is an important limitation. Once interest rates are near zero, the central bank cannot cut them much further, a situation Keynes called a liquidity trap. This is why central banks turned to quantitative easing after 2008, and why fiscal policy is often seen as more effective in deep recessions.

Monetary policy is also poorly suited to cost-push inflation. If inflation is caused by a rise in energy prices, raising interest rates reduces AD and inflation, but at the cost of lower output and higher unemployment: the central bank faces a trade-off.

Key point

Monetary policy is fast to change and politically independent, but works with long lags and loses power when rates are near zero or confidence is very low.

Quick check

1. What is the zero lower bound?

2. Why is monetary policy weak against cost-push inflation?

3. Give one strength of monetary policy.

Answers: 1. rates cannot easily be cut below zero 2. reducing AD lowers inflation only by reducing output and jobs 3. quick, incremental, independent, credible

8 Money creation by commercial banks (HL only)

Most money is created by commercial banks when they make loans.

HL only

This section is Additional Higher Level content. SL students do not need it.

Most of the money in an economy is not notes and coins but bank deposits, and most deposits are created by commercial banks when they lend. Under a fractional reserve banking system, banks keep only a fraction of deposits as reserves and lend the rest.

Suppose a bank receives a new deposit of $10 000 and the reserve requirement is 20%. It keeps $2 000 and lends $8 000. The borrower spends it, and the recipient deposits it in another bank, which keeps $1 600 and lends $6 400, and so on. Each round creates new deposits, and the total money supply grows by a multiple of the original deposit.

Money multiplier = 1 ÷ reserve requirement Maximum increase in money supply = money multiplier × initial deposit

WORKED EXAMPLE 2 Money creation

A bank receives a new deposit of $10 000. The reserve requirement is 20%. Calculate the money multiplier and the maximum increase in the money supply.

Solution

Money multiplier = 1 ÷ 0.2 = 5M1 A1

Maximum increase = 5 × 10 000 = $50 000A1

In practice the actual multiplier is smaller, because banks hold extra reserves, people hold some cash, and banks lend only if there are willing and creditworthy borrowers. This is why the money supply did not grow as much as reserves after 2008. The central bank influences money creation through the reserve requirement, the policy rate and open market operations.

Quick check

1. What is fractional reserve banking?

2. Calculate the money multiplier if the reserve requirement is 10%.

3. Why is the actual multiplier usually smaller?

Answers: 1. banks keep a fraction of deposits as reserves and lend the rest 2. 10 3. banks hold extra reserves; people hold cash; weak loan demand

9 The role of the central bank

Functions.

A central bank issues currency, acts as banker to the government and commercial banks, is lender of last resort, regulates the financial system and conducts monetary policy. Most central banks are independent of government.

WORKED EXAMPLE 3 Independence (standard)

Explain why central bank independence can help control inflation.

Solution

Decisions are free from short-term political pressureR1

Credible commitment to inflation targets anchors expectationsR1

10 Inflation targeting

A clear goal.

Many central banks target inflation, often 2% (Bank of England, ECB, US Federal Reserve). A clear target anchors expectations: if people expect 2% inflation, wage and price setting stays moderate.

Quick check

1. Why do central banks target low positive inflation rather than zero?

Answers: 1. avoid deflation risk and allow flexibility in relative prices and wages

11 How interest rates affect AD

The transmission mechanism.

A cut in the policy interest rate lowers commercial borrowing rates: borrowing becomes cheaper and saving less attractive, so consumption and investment rise; mortgage payments fall, raising disposable income; asset prices rise (wealth effect); the currency may depreciate, boosting net exports. AD increases.

WORKED EXAMPLE 4 Transmission (exam level)

Explain three ways a cut in interest rates increases AD.

Solution

Cheaper borrowing: more consumption and investmentR1

Lower mortgage payments raise disposable incomeR1

Currency depreciation increases net exportsR1

12 Expansionary monetary policy

Fighting recession.

In a recession, the central bank cuts interest rates or increases the money supply to raise AD, output and employment.

Figure 4. Expansionary monetary policy shifts AD right.

Quick check

1. Why might expansionary monetary policy be weak in a deep recession?

Answers: 1. low confidence: firms and households may not borrow even at low rates

13 Contractionary monetary policy

Fighting inflation.

When inflation is above target, the central bank raises interest rates, reducing borrowing and spending, so AD and inflationary pressure fall.

WORKED EXAMPLE 5 Rate rise (standard)

Explain how higher interest rates reduce inflation.

Solution

Borrowing costs rise; saving more attractiveR1

Consumption and investment fall; AD falls; inflation pressure easesR1

In the real world

Between 2022 and 2023, the US Federal Reserve raised its policy rate from near 0% to over 5% to bring inflation down from about 9%.

14 Tools of monetary policy

Beyond the base rate.

Tool	How it works
policy interest rate	influences all borrowing and saving rates
open market operations	buying/selling bonds changes money supply
minimum reserve requirements	changes banks' ability to lend
quantitative easing (QE)	large-scale asset purchases to lower long-term rates
forward guidance	signals future policy to shape expectations

15 Quantitative easing

When rates are near zero.

When interest rates are near zero, central banks may buy government bonds and other assets (QE), increasing money in the banking system and lowering long-term interest rates, encouraging borrowing and investment.

WORKED EXAMPLE 6 QE (exam level)

Explain how quantitative easing aims to increase AD.

Solution

Asset purchases raise bond prices and lower long-term yieldsR1

Cheaper borrowing and higher asset prices encourage spendingR1

16 Real interest rates

Adjusting for inflation.

Real interest rate ≈ nominal interest rate − inflation. Negative real rates encourage borrowing and discourage saving; high real rates do the opposite.

WORKED EXAMPLE 7 Real rate (standard)

The nominal interest rate is 3% and inflation 5%. Calculate the real interest rate.

Solution

3 − 5M1

= −2%A1

17 Evaluating monetary policy

Strengths and limitations.

Strengths: decisions are quick and reversible; independent central banks are credible; can be adjusted in small steps. Limitations: time lags (12–24 months), weak in deep recessions (liquidity trap), affects all regions and sectors, may cause asset bubbles and harm savers.

WORKED EXAMPLE 8 Liquidity trap (exam level)

What is a liquidity trap?

Solution

Interest rates near zero cannot be cut furtherR1

Monetary policy loses effectiveness in stimulating demandR1

18 Monetary policy and exchange rates

International effects.

Higher interest rates attract foreign financial capital, increasing demand for the currency and causing appreciation; this lowers import prices (reducing inflation) but harms export competitiveness.

Quick check

1. How can a rate rise reduce inflation through the exchange rate?

Answers: 1. currency appreciates; import prices fall

19 Demand and supply of money (HL)

Equilibrium interest rate.

The interest rate is determined by the demand for money (falling as interest rates rise) and the money supply (set by the central bank, vertical). Increasing the money supply lowers the equilibrium interest rate.

WORKED EXAMPLE 9 Money market (exam level)

Explain the effect of an increase in money supply on the interest rate.

Solution

Money supply curve shifts rightR1

Equilibrium interest rate fallsR1

20 Commercial banks and money creation (HL)

Fractional reserve banking.

Commercial banks create money by lending: deposits are partly kept as reserves and partly lent out, creating new deposits. The money multiplier = 1/reserve ratio (maximum).

WORKED EXAMPLE 10 Money multiplier (exam level)

A reserve requirement is 10%. A new deposit of $1000 is made. Calculate the maximum increase in the money supply.

Solution

Multiplier = 1/0.1 = 10M1

Maximum = $10 000A1

21 Mixed review: worked problems

Bringing the ideas together.

WORKED EXAMPLE 11 Mixed problem (exam level)

Compare monetary and fiscal policy in fighting a recession.

Solution

Monetary: quick decisions, independent, but weak near zero ratesR1

Fiscal: direct effect on AD, targeted, but lags and debt concernsR1

Often used togetherR1

22 Additional exam-style practice

Paper 1 and Paper 2.

WORKED EXAMPLE 12 Paper 1 part (b) (exam level)

Using real-world examples, evaluate the effectiveness of monetary policy in controlling inflation. [15]

Solution

Transmission mechanism with diagramR1 R1

Examples (2022–2023 rate rises)R1

Lags, supply-side inflation, costs to borrowers; judgementR1 R1

23 Monetary policy and cost-push inflation

A difficult case.

When inflation comes from supply shocks (energy prices), raising interest rates reduces AD and inflation but deepens the fall in output. Central banks must balance inflation control against recession risk.

Quick check

1. Why is monetary policy less suited to cost-push inflation?

Answers: 1. it reduces demand, worsening the output loss from the supply shock

24 Distributional effects of monetary policy

Winners and losers.

Low interest rates and QE raise asset prices, benefiting wealthier households who own assets; savers receive low returns; borrowers benefit. Rising rates hurt mortgage holders and indebted firms.

Quick check

1. Why might QE increase wealth inequality?

Answers: 1. asset prices rise, benefiting those who already own assets

25 Common misconceptions and links

Students often think…	Actually…
lower interest rates increase saving	they reduce the reward for saving, so spending tends to rise
monetary policy is set by the government	it is set by an independent central bank in most countries
the central bank can always boost demand	at the zero lower bound and with low confidence it is weak
monetary policy works quickly	lags of up to two years
banks lend out only the money people deposit	lending creates new deposits: money creation

How 3.6 connects to the rest of the course

Topic	Connection
3.2 AD/AS	monetary policy shifts AD
3.3 Objectives	inflation targets
3.5 Fiscal policy	comparison of demand-side tools
4.5 Exchange rates	interest rates affect the currency

26 Exam-style question with markscheme

Try this under exam conditions (about 18 minutes) before reading the markscheme.

Figure 5. Central bank interest rate and inflation.

Text A. Inflation rose sharply in 2022 because of higher energy prices and strong demand after the pandemic. The central bank raised its policy rate from 0.1% to over 5% within two years.

(a) Calculate the real interest rate in 2022. [2]

(b) Explain why the central bank raised interest rates in 2022 and 2023. [3]

(d) Explain why inflation did not fall immediately. [2]

(e) The reserve requirement is 12.5%. Calculate the maximum increase in the money supply from a $40 m deposit. [2]

Markscheme

Part	Answer	Marks
(a)	2.25 − 8.0	M1
	= −5.75%	A1
(b)	inflation far above the 2% target	R1
	higher rates reduce borrowing and AD	R1
	anchor inflation expectations	R1
(c)	higher borrowing costs; more saving	R1
	lower C and I; lower asset prices	R1
	currency appreciates; net exports fall	R1
(d)	time lags of 18 to 24 months	R1
	supply-side causes not affected by interest rates	R1
(e)	multiplier = 1 ÷ 0.125 = 8	M1
	8 × 40 = $320 m	A1

Examiner's comments. In (c), the best answers traced at least three channels. In (d), many candidates missed that part of the inflation was cost-push, which interest rates address only indirectly.

27 Check your understanding

Section A: multiple choice

1. Monetary policy is conducted by

A. the central bank B. the finance ministry C. commercial banks D. parliament

2. Raising interest rates is likely to

A. increase borrowing B. raise asset prices C. reduce consumption and investment D. increase AD

3. Open market purchases of bonds by the central bank

A. decrease the money supply B. increase the money supply C. raise interest rates D. have no effect

4. Quantitative easing involves

A. raising taxes B. selling bonds to banks C. fixing the exchange rate D. large-scale buying of bonds to increase the money supply

5. A liquidity trap occurs when

A. rates are very high B. interest rates are near zero and further cuts are ineffective C. inflation is high D. banks lend too much

6. If nominal rates are 5% and inflation 8%, the real rate is

A. −3% B. 3% C. 13% D. 0.6%

7. Lower interest rates may cause the currency to

A. appreciate B. stay fixed C. disappear D. depreciate

8. Central bank independence aims to

A. increase government spending B. reduce taxes C. make inflation targets credible D. fix the exchange rate

9. If the reserve ratio is 10%, the money multiplier is

A. 0.1 B. 1 C. 100 D. 10

Section B: structured

10. Explain the transmission mechanism of an interest rate cut. [4]

11. Explain two tools of monetary policy. [4]

12. Evaluate the effectiveness of monetary policy in a deep recession. [8]

13. Explain how commercial banks create money. [4]

Answers

1. A 2. C 3. B 4. D 5. B 6. A 7. D 8. C 9. D

10. Cheaper borrowing raises C and I; asset prices rise; currency depreciates raising net exports; AD shifts right.

11. e.g. policy rate; open market operations (buy bonds raises money supply).

12. Quick and credible, but lags, zero lower bound, low confidence (pushing on a string); QE as alternative; fiscal policy may be needed; judgement.

13. Banks keep a fraction of deposits and lend the rest; loans become new deposits; money supply rises by up to 1 ÷ reserve ratio.

28 Summary and topic map

Idea	Remember
Monetary policy	interest rates and money supply set by the central bank
Tools	policy rate, OMO, reserve requirements, QE
Transmission	C, I, asset prices, exchange rate, AD
Expansionary	cut rates, buy bonds
Contractionary	raise rates, sell bonds
Inflation targeting	anchors expectations; independence
Limitations	lags, zero lower bound, low confidence, cost-push
Money creation (HL)	multiplier = 1 ÷ reserve requirement

Before the exam, make sure you…

•trace the transmission mechanism step by step
•use real interest rates where inflation is high
•evaluate with lags and the zero lower bound
•compare with fiscal policy in recessions

Monetary Policy on one page

Cover this page with a sheet of paper and try to rebuild it from memory. Whatever you can't recall is what to revise next.

Figure 6. Topic map for Monetary Policy.

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