How Are Fixed and Managed Exchange Rates Maintained?
A floating rate changes with currency demand and supply. A fixed rate commits authorities to a stated parity. Managed floating allows the rate to move while authorities intervene to influence it, sometimes within a band. Stable data alone do not identify the arrangement: ask what officials promise to maintain.
Builds on: How Do Exchange Rates Affect Prices and Output?
What you will learn
- A fixed rate is a policy commitment, not merely a stable observation.
- Trace reserve transactions used to defend a peg
- Evaluate credibility, reserves and monetary-policy constraints
Essential definitions
- Floating exchange rate
- A rate determined mainly by market demand and supply.
- Fixed exchange rate
- A system committing the currency to an official parity against another currency or benchmark.
- Managed floating
- Market determination with intervention to influence the rate, sometimes within a band.
- Devaluation
- An official reduction in a fixed exchange-rate parity.
- Revaluation
- An official increase in a fixed exchange-rate parity.
- Overvalued currency
- An official rate above the market-clearing rate in the stated foreign-currency-per-domestic-unit quote.
- Undervalued currency
- An official rate below that market-clearing rate, with excess private demand for domestic currency.
- Exchange controls
- Government restrictions on converting currencies or making payments across borders.
- Capital controls
- Restrictions on cross-border financial transactions, such as acquiring foreign assets or transferring investment funds.
Identify the commitment and read the peg
A floating rate changes with currency demand and supply. A fixed rate commits authorities to a stated parity. Managed floating allows the rate to move while authorities intervene to influence it, sometimes within a band. Stable data alone do not identify the arrangement: ask what officials promise to maintain.
The currency diagrams put foreign currency per domestic unit vertically and domestic currency quantity per period horizontally. In the fixed diagram, E is the private-market intersection. The peg is above that rate, so domestic currency supplied exceeds the amount private buyers demand. Read both quantities at the peg; the central bank must buy the gap to maintain it.
Follow intervention in each direction
To resist depreciation, the bank sells foreign reserves and buys domestic currency. This absorbs excess supply, but reserve holdings decline. Higher interest rates may attract asset buyers and currency demand, provided risk and expectations do not offset the return. They can also reduce domestic borrowing and employment.
To resist appreciation, the bank buys foreign currency and supplies domestic currency. Reserves rise and domestic liquidity may increase unless separate operations offset it. In the managed diagram, E1 is the starting intersection, the hollow point shows the market outcome without intervention, and E2 the final intersection after the intervention shift. Devaluation lowers an official fixed parity; revaluation raises it. Defending the unchanged peg does neither.
Exchange controls and their limits
Exchange controls restrict selected conversions or external payments; capital controls restrict cross-border financial transactions. Limiting residents' foreign-asset purchases can reduce sales of domestic currency to obtain foreign funds. During capital flight, this may slow reserve depletion and downward rate pressure.
The incentive to move funds can remain. Controls may obstruct legitimate transactions, encourage evasion and weaken investor confidence, making later finance harder. Evaluate enforcement and economic costs against reserves, interest rates or a changed parity. No instrument guarantees an unsustainable commitment can be maintained indefinitely.
Hypothetical reserve defence
- The central bank promises 1 domestic unit = 0.50 foreign units.
- At the peg, the market has excess supply of 200 million domestic units.
- The bank buys those domestic units using 200 million × 0.50 = 100 million foreign reserve units.
One intervention uses 100 million units of foreign reserves; repeated pressure can exhaust available reserves.
Defending an overvalued fixed parity
At a peg above the market-clearing rate, private supply exceeds private demand. The central bank buys the excess domestic currency with foreign reserves to maintain the peg.
How to read this diagram
- Draw the private-market equilibrium E.
- Add the peg above it.
- At the peg mark private Qd and Qs; central-bank purchases must fill that gap.
E is the private-market equilibrium at 0.90. At the 1.00 peg, private Qs = 70 and Qd = 50. The central bank buys 20 million domestic units, spending 20 million foreign units.
On a small screen, scroll the graph horizontally to read all labels.
Assumptions and limits: The stated market curves exclude the intervention. Reserves are finite; expectations and interest rates are held fixed.
Managed exchange rate: resisting appreciation
After private demand rises, the central bank sells domestic currency and buys foreign currency. The added supply limits appreciation and increases foreign reserves.
How to read this diagram
- Shift D1 right to D2.
- Mark E1 at the original D1–S1 intersection and a hollow point at the floating outcome without intervention.
- Add official supply, shifting S1 to S2 and mark the final equilibrium E2 at D2–S2, below that floating rate.
Start at E1 (60 million, 0.90). Without intervention the demand increase would raise the rate to 1.00 at the hollow point. Official domestic-currency sales shift supply right, leaving E2 at 75 million and 0.95.
On a small screen, scroll the graph horizontally to read all labels.
Assumptions and limits: The illustration targets a rate between the original and new floating equilibria. It does not imply every managed float has a fixed target.
Apply and evaluate
- Maintaining a peg requires enough reserves or other effective measures to balance transactions at the announced price.
- Intervention that holds the rate constant is different from changing the official parity.
Common misconceptions
- Devaluation and depreciation are not interchangeable terms.
- A central-bank purchase that preserves an unchanged peg is not automatically revaluation.
Knowledge check
How does selling foreign reserves support the domestic currency?
What to remember
A fixed rate is a policy commitment, not merely a stable observation. Intervention, interest rates and controls can support it, but each uses resources or imposes economic costs.
Completion records your reflection, not a test score.
Lessons in this section
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