CFA Level II Exam · Currency Exchange Rates: Understanding Equilibrium Value

Monetary and Fiscal Policy Effects on Currencies

Updated 7 October 2026 · Fact-checked

Policy affects a currency through interest rates, capital flows and expected inflation. Tight money with loose fiscal policy usually lifts a currency when capital is mobile. Loose money with tight fiscal policy usually weakens it. The Dornbusch model says that after a monetary shock, the exchange rate first overshoots its long-run value, then converges as prices adjust.

Understand Monetary and Fiscal Policy Effects on Currencies

Exchange rates respond to policy mainly through capital flows. If a country's real interest rates rise relative to others, investors move capital there to earn the higher return. Demand for the domestic currency rises and it tends to appreciate. If real rates fall, the opposite happens.

Monetary policy is set by the central bank. Fiscal policy is set by the government through taxes and spending. The combination is the policy mix. Each can be expansionary or contractionary, giving four combinations. The currency effect depends on how each piece moves interest rates and capital flows.

Expansionary fiscal policy raises the budget deficit and pushes up demand for funds and interest rates. It also raises domestic demand and imports. The net effect depends on capital mobility (the Mundell-Fleming framework). With high capital mobility, fiscal expansion raises rates, capital inflows dominate, and the currency appreciates. With low capital mobility, the rise in imports dominates and fiscal expansion depreciates the currency. Expansionary monetary policy lowers interest rates and tends to weaken the currency.

The Dornbusch overshooting model explains why exchange rates are so volatile. It assumes goods prices are sticky in the short run, while financial markets and exchange rates adjust at once. Purchasing power parity (PPP) holds only in the long run. Suppose the central bank unexpectedly increases the nominal money supply. Prices cannot rise immediately, so the real money supply rises. This lowers domestic nominal interest rates, and with prices fixed and inflation expectations unchanged in the short run, real rates fall too. Lower rates push capital out, so the domestic currency depreciates immediately. To keep investors indifferent, the domestic currency must then be expected to appreciate. That requires it to fall below its new long-run value first. So it depreciates by more than the long-run PPP change (it overshoots), then rises gradually as prices climb.

The model implies that a monetary expansion causes a large immediate fall in the currency and a partial recovery later. Long-run depreciation equals the proportional rise in money supply and prices. The short-run drop is larger. A monetary contraction works in reverse: the currency overshoots upward, then drifts down.

You must also remember the limits. The effects above hold when capital is mobile. Large deficits can weaken a currency if investors worry about debt sustainability or inflation, or if they demand a risk premium.

Key formulas to remember

Policy mix: expansionary fiscal, tight monetary: High interest rates + strong domestic demand → capital inflows → domestic currency appreciates (strongly); Holds with high capital mobility. With low capital mobility, fiscal expansion raises imports and depreciates the currency.
Policy mix: tight fiscal, expansionary monetary: Low interest rates + weaker demand → capital outflows → domestic currency depreciates; The opposite of the case above.
Policy mix: both expansionary: Fiscal pushes rates up, monetary pushes rates down → currency effect ambiguous; usually weaker due to lower rates and inflation fears; Check the question for which effect the vignette emphasizes. Both tight is also ambiguous, with rates effects offsetting.
Dornbusch overshooting: Monetary expansion → immediate depreciation larger than long-run depreciation → gradual partial appreciation as prices rise; Needs sticky goods prices and PPP holding only in the long run.
Long-run effect of money supply change: Long-run % change in spot rate (domestic per foreign) ≈ % change in money supply (PPP holds in long run, real variables unchanged); Short-run change is bigger in size, with the same direction.
Real interest rate: Real rate ≈ nominal rate − expected inflation; Capital flows respond to real rate differentials, not nominal rates alone.

How to solve Monetary and Fiscal Policy Effects on Currencies questions

Use this sequence for any vignette on policy and currencies. Work from the policy stance to rates to flows to the exchange rate.

1Identify the quoted direction of the currency: price of the domestic currency or price of foreign currency. Note whether an increase means appreciation.
2Classify monetary policy as expansionary or contractionary from the vignette data (rate cuts, money growth, bond purchases).
3Classify fiscal policy the same way (deficit increase, tax cuts, spending cuts).
4Work out the effect on real interest rates, using expected inflation. Higher expected inflation lowers the real rate.
5Predict the capital flow direction and the short-run currency move. Higher real rates attract capital and lift the currency.
6If the question mentions sticky prices or shocks, apply Dornbusch: short-run move overshoots, long-run move equals the change in money supply and prices.
7Check for exceptions in the vignette: debt worries, risk premia, or limited capital mobility. Adjust your answer if the vignette states them.
8Choose the option that matches your direction and size (short run versus long run).

Quickest way: Rates-first shortcut

When to use it: Use this when time is short and the question asks only for direction of the currency or which policy mix is most favourable.

Ask only: which way do real interest rates move?
Higher real rates mean the currency strengthens; lower real rates mean it weakens.
For a mix, tight monetary dominates the rate effect; fiscal expansion adds to rates and demand.
For Dornbusch, remember: short run is overshoot, long run is PPP. After the shock, the currency moves back toward the long-run value.
Eliminate any option that says the long-run move is larger than the short-run move after a monetary shock.

Common mistakes in Monetary and Fiscal Policy Effects on Currencies

Saying monetary expansion causes only a one-time depreciation to the long-run level.
Students forget that sticky prices make the short-run move bigger than the PPP level.
Fix: Remember the order: jump past the long-run value, then reverse partway.
Assuming a larger fiscal deficit always weakens the currency.
Deficits sound bad, so students link them with weakness.
Fix: With mobile capital and tight money, the higher rates attract inflows and strengthen the currency. Weakness comes with low capital mobility or when the vignette cites debt or inflation fears.
Using nominal rates instead of real rates.
The vignette gives nominal rates prominently.
Fix: Subtract expected inflation first and compare real rates across countries.
Mixing up the direction of the exchange rate quote.
A rise in the quote of domestic per foreign means domestic depreciation, which feels backwards.
Fix: Write down the quote convention first and label every move as appreciation or depreciation.
Treating the policy mix with both expansionary or both contractionary as having a clear answer.
Students want one clean rule.
Fix: State that the effects are ambiguous and use the vignette's emphasis on rates, growth or inflation to decide.

Worked examples

Example 1

Vignette: Country A's central bank has cut its policy rate while expected inflation is unchanged. The government is cutting spending to reduce its deficit. Country B has stable policy. Questions: (1) What is the likely effect on Country A's currency? (2) Which policy mix describes Country A?

Show the solution

Monetary policy in A is expansionary: the rate cut with unchanged inflation expectations lowers real rates.
Fiscal policy in A is contractionary: spending cuts reduce the deficit and reduce demand.
The monetary expansion lowers rates, and fiscal contraction reduces the deficit and demand, so it does not offset the fall in rates.
Lower real rates relative to B drive capital out of A, so A's currency is likely to depreciate.

Answer: (1) Country A's currency is likely to depreciate, driven by lower real rates. (2) Expansionary monetary policy with contractionary fiscal policy.

Example 2

Vignette: The domestic central bank unexpectedly raises the money supply by 4%. Prices are sticky in the short run, and PPP holds in the long run. The spot rate is quoted as domestic currency per foreign currency, currently 20.00. Questions: (1) What is the long-run spot rate? (2) Which statement about the short-run spot rate is consistent with the Dornbusch model?

Show the solution

Long-run depreciation equals the money supply increase of 4%, so the quote rises by 4% (domestic per foreign rises when the domestic currency weakens).
Long-run spot = 20.00 × 1.04 = 20.80.
Short run: prices cannot adjust, so the real money supply rises and domestic nominal and real rates fall. The domestic currency depreciates by more than 4%.
So the short-run spot is above 20.80, and then it falls back toward 20.80 as prices rise.

Answer: (1) 20.80 domestic per foreign. (2) The short-run spot rate overshoots to a value above 20.80, then declines gradually toward 20.80.

Exam tips

Always write the quote convention before reasoning about direction; many wrong answers come from reversed quotes.
When the vignette gives a numeric money supply change, use it for the long-run PPP move and expect the short-run move to be larger.
Look for hints about debt, risk premia or capital controls. They signal that the simple rates-and-flows answer may not apply.
For policy mixes, name both the monetary and fiscal stance explicitly before choosing the effect.
Link this topic to capital market expectations questions, where policy mix feeds into forecasts of currency and asset returns.

Monetary and Fiscal Policy Effects on Currencies in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Monetary and Fiscal Policy Effects on Currencies: frequently asked questions

What is the Dornbusch overshooting model?

It is a model in which goods prices are sticky but exchange rates adjust instantly. A monetary shock moves the exchange rate past its long-run level in the short run, then it gradually converges as prices adjust. It explains why exchange rates are more volatile than prices.

How does monetary policy affect currency value?

Contractionary policy raises real interest rates, attracts capital, and tends to strengthen the currency. Expansionary policy lowers real rates and tends to weaken it. Expected inflation also matters, since higher inflation erodes real returns.

Which policy mix is best for a currency?

With high capital mobility, tight monetary policy combined with expansionary fiscal policy is usually the strongest for appreciation, since it gives high interest rates and strong demand. Loose monetary with tight fiscal policy is usually the weakest. Both loose or both tight give ambiguous results.

Does the overshooting model hold in the long run?

In the long run, PPP holds and the exchange rate settles at the level implied by the change in money supply and prices. Overshooting is a short-run effect that arises from sticky prices.