Cambridge O Level Economics: Monetary policy (2281)

This guide teaches Monetary policy, sections 4.4.1 to 4.4.3, from the Cambridge O Level Economics 2281 syllabus for examination in 2026 (topic 4, Government and the macroeconomy). The syllabus is not tiered. The countries, firms and numbers here are all made up. For quick recall use the revision notes, then test yourself with the practice set. The course hub and printable checklist show the rest of the syllabus, and the free diagnostics show where you are weakest.

Scope of the unit

Section	Required skill
4.4.1	Say what money supply and monetary policy mean
4.4.2	Describe the measures: interest rate changes, money supply changes and foreign exchange rate changes
4.4.3	Explain how these measures may enable the government to achieve its macroeconomic aims

The aims are set out in section 4.2. There are five: growth in output, work for those who want it, stable prices, balance of payments stability, and a fairer spread of income. For money, banks and the central bank see the money and banking guide.

4.4.1 Definitions

Money supply is the stock of money held by households and firms in a country at a given moment: notes and coins in circulation plus the balances in bank accounts.

Monetary policy is action by the government, usually carried out by its central bank, on the cost of borrowing, the quantity of money and the value of the currency, in order to steer the economy towards its macroeconomic aims.

Monetary policy works through money and credit. Fiscal policy (4.3) works through taxation and government spending. Keep the two apart in answers.

4.4.2 The measures

Interest rates

An interest rate is what a borrower pays for a loan and what a saver is paid, as a percentage of the sum. The central bank sets a key rate, and high street banks usually shift the rates they charge and pay the same way.

Raise the rate (tight policy):

1. Loans cost more, so households and firms borrow and spend less.
2. Saving pays more, so more is saved and less spent.
3. Total spending grows more slowly.

Cut the rate (loose policy) reverses each step.

Worked example 1 (invented). A firm in Country A has a loan of 200,000 A-dollars. At 6% the yearly interest is 200,000 × 0.06 = 12,000. At 9% it is 200,000 × 0.09 = 18,000. The rise is 6,000, which is 6,000 ÷ 12,000 × 100 = 50% more interest, although the rate rose by only 3 percentage points. A household with an interest-only mortgage of 90,000 pays 90,000 × 0.04 ÷ 12 = 300 a month at 4% and 450 a month at 6%. The extra 150 is 150 ÷ 2,400 × 100 = 6.25% of a monthly after-tax income of 2,400.

Real and nominal rates. The nominal rate is the rate quoted. The real rate allows for inflation: approximately nominal rate minus inflation rate.

Worked example 2 (invented). A saver in Country A earns 5% while inflation is 3%. The real rate is about 5 − 3 = 2%. If inflation rises to 6% the real rate is about 5 − 6 = −1%. Check: 1,000 grows to 1,050, but prices rose 6%, so its buying power is 1,050 ÷ 1.06 = 990.57, a real loss of about 9.43. Savers still have reason to save only if the real return is acceptable, and borrowers gain when the real rate is negative.

Money supply

A government can try to change the amount of money, or the amount of credit banks can create, in several ways:

• The central bank sells government bonds to the public and banks, which takes money out of circulation. Buying bonds puts money in.
• It raises or lowers the share of deposits banks must hold back as reserves (a reserve requirement).
• It limits or encourages bank lending directly.

Worked example 3 (invented, simplified). A new deposit of 1,000 enters the banks of Country A. Banks must keep 10% in reserve and lend the rest. They lend 900, which is spent and deposited again. Then they lend 810, then 729, and so on. The total of all deposits is 1,000 ÷ 0.10 = 10,000, so banks have created 9,000 of new lending. If the requirement rises to 20%, the total is 1,000 ÷ 0.20 = 5,000 and new lending falls to 4,000. This assumes no cash is held outside banks and every loan is redeposited.

A larger money supply makes credit easier to get and is a loose policy. A smaller one is tight. If the money supply grows faster than output, spending can outrun what the economy produces and prices may rise. In Country A the money supply grows from 400 billion to 424 billion: (424 − 400) ÷ 400 × 100 = 6%. With real output growth of 2%, the gap is 4 points.

Foreign exchange rates

An exchange rate shows how much of one currency is needed to buy a unit of another. A government can influence it through the interest rate, because foreign savers chasing a higher return must first buy the currency, or by having the central bank buy or sell the currency itself.

Worked example 4 (invented). Country A exports a machine at 1,000 A-dollars. Country B imports a good costing 300 B-dollars.

Rate	Machine in B-dollars	B-good in A-dollars
1 A-dollar = 0.50 B-dollars	500	300 ÷ 0.50 = 600
A-dollar rises to 0.60	600 (up 20%)	300 ÷ 0.60 = 500 (down 16.7%)
A-dollar falls to 0.40	400 (down 20%)	300 ÷ 0.40 = 750 (up 25%)

A higher rate (appreciation) makes exports dearer abroad and imports cheaper. A lower rate (depreciation) does the opposite. The size of the response depends on price elasticity of demand. If demand for the machine has elasticity 1.5, a 20% fall in its foreign price raises the quantity sold by about 1.5 × 20 = 30%.

Diagram in words: draw a market for A-dollars with the exchange rate (B-dollars per A-dollar) on the vertical axis and the quantity of A-dollars on the horizontal axis. If foreign savers want A-dollars because the interest rate rose, the demand curve shifts right and the equilibrium rate rises from 0.50 to a higher value.

4.4.3 Effects on the government’s aims

Aim	Tight policy (higher rates, smaller money supply, stronger currency)	Loose policy (lower rates, larger money supply, weaker currency)
Stable prices	Slows spending; cheaper imports; lower inflation	Faster spending; dearer imports; higher inflation risk
Economic growth	Slower: less borrowing and investment	Faster: more borrowing and investment
Full employment	Weaker demand for workers; unemployment may rise	More demand for workers; unemployment may fall
Balance of payments	Dearer exports and cheaper imports worsen the current account	Cheaper exports and dearer imports can improve it
Redistribution	Savers gain, borrowers lose	Borrowers gain, savers lose

Chain for growth and jobs. Lower interest rate → cheaper loans → firms invest more and households buy more on credit → firms sell more → output grows → firms hire more → unemployment falls. Each arrow needs to hold for the policy to work.

Chain for inflation. Higher interest rate → less borrowing and more saving → lower spending → firms cannot raise prices as easily → inflation slows. Stronger currency → cheaper imported materials and goods → lower costs and prices.

Evaluation: why the effects may not happen

• Confidence. In a gloomy economy, firms may not borrow even at low rates.
• Time lags. Effects can take many months to appear.
• Cost-push inflation. If prices rise because of dearer imported oil or higher wages, a rate rise treats the symptom and may cut output.
• Banks. They may refuse to lend or may not pass on a rate change.
• Elasticity. A weaker currency helps exports only if foreign demand responds, and it makes imported inputs dearer.
• Conflicts. A rate cut for jobs can raise inflation; a stronger currency for lower prices can hurt exporters and jobs; a boost to growth may suck in imports and worsen the balance of payments.

Worked example 5 (invented). Country C has inflation of 9% and a large current account deficit. The central bank raises its rate from 5% to 8% and the currency appreciates. Strengths: spending falls, imports cost less, inflation slows. Weaknesses: exports become dearer, so the deficit may not shrink; growth slows; firms with loans cut jobs. Judgement: it suits demand-led inflation, but if the inflation comes from rising import costs the gain is smaller. The best answer weighs the aim the government cares about most.

Common errors

• Writing “interest rates are the money supply”. They are separate measures.
• Saying a high exchange rate always helps the country. It helps import costs and hurts exports.
• Mixing up the direction of change: lower rates make borrowing cheaper, not dearer.
• Describing tax and spending changes as monetary policy.
• Giving effects with no chain of reasoning, or no evaluation when “discuss” or “evaluate” is asked.

Next steps

Work through the revision notes and then the practice set. The wider topic has its own practice questions.

Official syllabus

Cambridge O Level Economics 2281, syllabus for examination in 2026, published by Cambridge University Press & Assessment (Cambridge Assessment International Education): section 4.4, Monetary policy.