IB Economics Fixed Exchange Rates

Fixed Exchange Rates: The Government as Your Currency's Babysitter - IB Economics

Target Question:

What is a fixed exchange rate system and how do governments maintain it?

Is The Government The World's Most Overprotective Parent?

Imagine you're babysitting a toddler. Your one job is to make sure that toddler is safe - no running into traffic, no eating crayons, no staging a full meltdown in the supermarket. You intervene every 30 seconds. Constantly. Every time the child threatens chaos, you step in and restore order.

Now replace the toddler with a currency. Replace the babysitter with a central bank. And replace the meltdown with a currency crisis that endangers trade relationships, crushes exports, and collapses an economy.

That's basically a fixed exchange rate system.

In our last entry, we looked at floating exchange rates - where currencies roam free, going up and down according to whoever's buying and selling them that day. The floating system is basically leaving your currency free in the park and hoping it'll be fine.

A fixed exchange rate system is the opposite. The government - through its central bank - keeps the currency on a very short leash. It decides what the currency is worth, announces that number to the world, and then does whatever it takes to keep it exactly there.

What Is a Fixed Exchange Rate?

A fixed exchange rate system operates when the central bank actively buys and sells foreign currencies to maintain its currency's value at a set rate against another currency or a group of currencies.

The keyword there is actively. The market doesn't set the rate - the government does. And then the central bank spends real money, every single day if necessary, to defend that rate against the forces of supply and demand.

It's not a suggestion. It's a commitment. A promise to the world that says: "This is what our currency is worth. Full stop."

Why Would Governments Want To Do This?

Good question. Floating exchange rates require a lot less effort - why would a government voluntarily sign up for the exhausting job of "babysitting" a currency indefinitely?

There are two reasons:

1. Export competitiveness and import costs

The value of a currency directly determines how competitive a country's exports are and how expensive its imports are. A currency that's constantly swinging around creates insecurity for businesses trying to plan ahead, price their products, or sign long-term international contracts. By fixing the rate, a government encourages a predictable trading environment. Exporters know what they'll earn. Importers know what they'll pay.

2. Certainty, confidence, and economic stability

A fixed exchange rate tells the world: "We're serious about economic management." That predictability and confidence attracts foreign investment, supports the current account balance, and creates a more stable environment for economic growth and employment. For smaller, open economies that are heavily trade-dependent, to be able to provide such an environment is a survival strategy.

The Most Famous Peg in the World: Hong Kong

If you want a real-world example of a fixed exchange rate that's actually stood the test of time, look no further than Hong Kong.

Since 15 October 1983 - that's over 40 years and counting - the Hong Kong dollar has been pegged to the US dollar at a rate of HK$7.80 to US$1.

It has survived the Handover to China in 1997, the Asian Financial Crisis of 1997–98, the dot-com crash, the 2008 global financial crisis, a global pandemic, and social unrest. The peg has held through all of that.

The body responsible for maintaining it is the Hong Kong Monetary Authority (HKMA), which operates essentially as Hong Kong's central bank. Every time the HKD threatens to stray from its 7.80 anchor, the HKMA steps in - buying or selling currencies as required - to drag it back.

It is, without question, the world's most successful long-running currency peg. Understanding how it works is a great first step towards grasping fixed exchange rate mechanics.

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Devaluation: Deliberately Making Your Currency Cheaper

Within a fixed exchange rate system, a government can occasionally decide to officially lower the value of its currency. This is called devaluation.

Devaluation is the official reduction of a currency's value within a fixed exchange rate system, carried out by the government or central bank. It makes a country's exports cheaper and imports more expensive, and differs from depreciation, which is an automatic market-driven fall in value.

Some of my students confuse this with depreciation but it is not quite the same. Depreciation happens automatically in a floating system when market forces drive the currency down. Devaluation is a deliberate policy decision. The government chooses to lower the peg. It's a choice, not a consequence.

Why would you choose to make your own currency worth less? Because it makes your exports cheaper for foreign buyers - instantly boosting export competitiveness. It also makes imports more expensive, which can reduce the import bill and help towards stabilising the trade balance.

Devaluation Diagram - How It Works in Practice

Let's use the Hong Kong example to walk through this.

Suppose the HKMA has fixed the value of the HK$ against the US$ at the rate FR (the fixed rate).

US consumers want to buy Hong Kong goods, so they buy HK$ to pay for them. This is demand for HK$ in the forex market.

Now imagine there's a surge in American demand for Hong Kong exports - HK tech products go viral, or Hong Kong financial services become incredibly popular. This causes demand for the HK$ to increase, shifting the demand curve from D1 to D2. The exchange rate would naturally rise to a new, higher equilibrium - let's call it ER.

But as economists often do, here we see the first problem: a higher exchange rate makes Hong Kong's exports more expensive for American buyers. That's the last thing Hong Kong wants. So the HKMA steps in and devalues the currency.

How? By increasing the supply of HK$ in the market - essentially printing and selling more HK$ - shifting the supply curve from S1 to S2. This extra supply makes up for the increased demand, pushing the exchange rate back down from ER to FR.

So, what is the final result? the HK$ stays at its fixed rate, exports remain competitive, and everyone's happy. Except maybe the currency traders who prematurely invested the wrong way.

Devaluation under a fixed exchange rate - demand for HK$ shifts right from D1 to D2, pushing rate to ER above FR. Government increases supply from S1 to S2 to bring exchange rate back down to FR. Source visit: IB Economics Diagrams

Revaluation: Making Your Currency More Expensive

The opposite of devaluation is revaluation:

Revaluation is the official increase in a currency's value within a fixed exchange rate system. A government may revalue its currency to reduce import costs or to manage inflation caused by strong export demand.

A government might choose to revalue upwards in order to:

• Make imports of essential goods and services cheaper (useful if the economy is struggling with high import costs)

• Manage inflation caused by excessive demand for its exports (if exports are booming, the economy can overheat - a stronger currency cools things down by making exports pricier)

Revaluation Diagram - How It Works in Practice

Hong Kong consumers go on a massive spending spree buying American goods - US cars, US tech, US streaming subscriptions. They need to sell HK$ and buy US$ to pay for all these imports.

This increases the supply of HK$ on the forex market (shift from S1 to S2), pushing the exchange rate down from FR towards a lower level ER.

But the HKMA wants to keep the rate at FR. So it steps in and buys HK ∗using its foreign currency reserves (i.e., it sells US). This:

a) Removes excess HK$ from the market, reducing supply

b) Increases the supply of US$ on the forex market (supply of US$ shifts from S1 to S2)

c) Reduces the value of the US$ and raises the price of HK$ back up from ER to FR

The fixed rate is restored. Currency: "baby-sitted"

Revaluation - consumers sell HK$ to buy US$ for imports, supply of HK$ shifts right from S1 to S2, exchange rate falls from FR to ER below FR. Government buys HK$ (sells US$) to restore exchange rate to FR. Source visit: IB Economics Diagrams

Revaluation - consumers buying US$ shifts demand for US$ from D1 to D2. Government sells US$ (supply of US$ shifts S1 to S2) to maintain the fixed exchange rate and bring HK$ back to FR. Source visit: IB Economics Diagrams

Managed Exchange Rates

Not every country wants the full commitment of a rigidly fixed exchange rate, and not every country is comfortable with a totally free float currency either. So we have the managed exchange rate - the sensible option in the middle for the risk-averse.

A managed exchange rate is a system in which a currency's value is primarily determined by market forces, but the central bank intervenes periodically to prevent excessive fluctuation or to correct significant overvaluation or undervaluation.

What is the key difference from a fixed rate? A managed system still fundamentally relies on market forces of currency demand and supply. The government doesn't set a specific target number and defends it at all costs. Instead, it supervises the rate, and when it drifts too far from what it considers appropriate, it intervenes and nudges it back. Similar to an attentive lifeguard - mostly letting things flow, but ready to dive in when needed.

We already met China's managed float (the "dirty float") in the previous entry. Now let's look at another real-world example: Singapore.

Managing Singapore's Dollar: The ±3% Band

The Monetary Authority of Singapore (MAS) allows the Singapore dollar (S$) to fluctuate against the US dollar by plus or minus 3 per cent around a central rate. This creates a corridor - a permitted range - within which the market can operate freely. But the moment the S$ approaches either edge of that band, the MAS steps in with correction measures.

Scenario A: S$ appreciating too fast

Suppose strong demand for Singapore's exports causes the demand for S$ to rise continuously - shifting from D1 to D2 - pushing the exchange rate up from ER1 towards ER2, threatening to break through the upper band. The MAS responds by increasing the supply of S∗ (selling S) from S1 to S2, flooding the market with Singapore dollars and pushing the rate back down towards ER1.

Scenario B: S$ depreciating too fast

If the exchange rate falls from ER1 down towards the lower band, the MAS steps in and buys S∗ using its foreign currency reserves. This increases demand for the S using its foreign currency reserves, lifting the exchange rate back towards ER1.

Singapore dollar managed exchange rate - exchange rate bands shown with upper and lower limits. D1 to D2 shift pushing ER up, MAS supply response from S1 to S2 restoring rate within band. Source visit: IB Economics Diagrams

Singapore has used this managed system brilliantly for decades. Because Singapore is an extraordinarily open, trade-dependent economy (total trade is roughly 3x its GDP - one of the highest ratios in the world), exchange rate stability is basic for the economic prosperity of the country. The MAS is widely regarded as one of the most sophisticated monetary authorities in Asia.

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Overvalued and Undervalued Currencies

In any managed or fixed system, a crucial question always lurks in the background: is the currency actually trading at its most accurate value?

An overvalued currency:

An overvalued currency is one whose exchange rate is set above the market equilibrium level, making exports more expensive and imports cheaper, and typically leading to a persistent balance of payments deficit.

Sounds great for shoppers. But a real disaster for exporters. Give it time and an overvalued currency will drag a country into a persistent balance of payments deficit, as imports surge and exports struggle.

An undervalued currency:

An undervalued currency is one whose exchange rate falls below its true market value, making exports artificially cheap and imports more expensive, which can cause imported inflation.

What is the issue here? It can trigger imported inflation, as the cost of essential goods bought from abroad rises.

Who Fixes It?

• In a freely floating system: market forces do the job automatically. If a currency is overvalued, too many imports flow in, supply of the domestic currency rises, and the exchange rate falls back towards equilibrium. No government needed.

• In a fixed or managed system: the central monetary authority must intervene:

  • If the currency is overvalued → the authority sells the currency to increase supply and lower its value

  • If the currency is undervalued → the authority buys the currency to increase demand and raise its value

Fixed vs Floating:

Now that we understand how fixed and managed systems work, let's weigh them up against floating exchange rates. This comparison appears in IB Economics exams regularly.

The key principle: the disadvantages of a fixed exchange rate system are generally the advantages of a floating system, and vice versa. They're two ends of the same trade-off.

1. Certainty and Stability

Fixed system advantage: Businesses operating internationally love predictability. If you know exactly what the exchange rate will be in six months, you can plan, price, and sign contracts with confidence. Trade and investment become more attractive because currency risk is removed. It also helps control speculation - there's less opportunity to profit from investing on rate movements if the rate is pinned.

Floating system disadvantage: A freely floating rate can swing dramatically, making it difficult for businesses to plan ahead and potentially hindering a government's ability to achieve macroeconomic goals like growth and price stability.

2. Opportunity Costs

Fixed system disadvantage: Defending a fixed rate is expensive. The central bank must intervene in currency markets, spending foreign reserves - money that could otherwise be invested in schools, hospitals, or infrastructure. It's the opportunity cost of playing currency babysitter 24/7. Mismanagement of reserves can lead to a crisis: when Argentina's fixed rate (pegged 1:1 to the US dollar from 1991 to 2001) finally collapsed, the country's foreign reserves had been almost entirely depleted invested in defending an unsustainable peg. The economic devastation lasted years.

Floating system disadvantage: Without intervention, currencies can experience wild swings that undermine macroeconomic stability.

3. Currency Liquidity

Fixed system disadvantage: Maintaining a fixed rate demands significant holdings of foreign currency reserves and assets (including gold reserves) to intervene as needed. Tying up vast amounts of reserves limits their availability for private investors and can also reduce the overall liquidity of the currency in global markets.

Floating system advantage: No need to hold massive reserves. Capital flows more freely and is available for other more productive uses.

4. Monetary Policy

This for economists is perhaps the most significant trade-off.

Fixed system disadvantage: Interest rates - the primary tool of monetary policy - are partly limited in a fixed exchange rate system.

In a fixed exchange rate system, the central bank's obligation to defend the exchange rate significantly limits its ability to use monetary policy independently - raising interest rates to stimulate or cool the economy risks pushing the currency away from its fixed rate.

Why? Because raising or lowering interest rates affects the currency's attractiveness to foreign investors (recall from our previous entry: higher rates attract capital inflows, pushing the currency up; lower rates push it down). If a government wants to lower rates to stimulate growth but in doing so the effect would be to weaken the currency beyond its fixed rate, it would be stuck. The fixed rate eats the monetary policy.

Floating system advantage: Full freedom to use monetary policy - raise rates to fight inflation, lower them to stimulate growth - without worrying about defending a currency peg. The Bank of England, the US Federal Reserve, and the ECB all benefit from this freedom.

The Current Reality

It's worth pausing here to note something your IB Economics teacher definitely knows: in today's globalised world, true fixed exchange rate systems are extremely rare.

Only a handful of economies - with the right combination of political will, foreign reserves, economic size, and institutional credibility - can sustain a fixed rate over the long term. Hong Kong is exceptional. Saudi Arabia and the UAE maintain pegs to the US dollar, largely because their oil revenues provide the dollar reserves needed to defend them. But for most countries, a rigid fixed rate is not a practical long-term option.

What's far more common is some version of a managed float - letting the market do most of the work, while retaining the right to intervene when things do not go according to plan. Singapore, China, India, and dozens of other economies follow this model or variations of it.

In the real world, the choice isn't just between "fixed vs floating." It's more of a sliding scale, and most countries sit somewhere in the middle.

IB Economics Summary

A useful way to remember all of this for the exam:

• Floating exchange rate = leaving the currency to raise itself. Risky. Wild. But free.

• Fixed exchange rate = hiring a very dedicated, very expensive babysitter who will sacrifice everything to keep the currency exactly where it's supposed to be.

• Managed exchange rate = hiring a part-time babysitter. They mostly let the currency do its thing, but they're checking in regularly and ready to step in if things go sideways.

Each approach has its good things. Each has its costs. The "right" choice depends entirely on the size, openness, and circumstances of the economy in question - and this is exactly the kind of refined answer that earns top marks in IB Economics Paper 1.

Frequently Asked Questions: Fixed Exchange Rates

Q1: What is a fixed exchange rate in IB Economics? A fixed exchange rate is a system where a government or central bank sets its currency's value at a specific rate against another currency or basket of currencies, and then actively buys and sells currencies in the forex market to maintain that rate. The Hong Kong dollar, pegged to the US dollar at HK$7.80 since 1983, is the most prominent real-world example.

Q2: What is the difference between devaluation and depreciation? Both refer to a fall in a currency's value, but they happen in different ways. Depreciation is an automatic, market-driven fall in a currency's value in a floating exchange rate system. Devaluation is a deliberate policy decision by a government to officially lower its currency's fixed rate - a choice, not a market outcome.

Q3: What is the difference between revaluation and appreciation? Appreciation is a market-driven increase in a currency's value in a floating system. Revaluation is an official, government-decided increase in a currency's fixed rate. Both result in a stronger currency, but one is a market outcome and the other is a policy decision.

Q4: What is a managed exchange rate? A managed exchange rate is a middle-ground system where a currency mostly floats with market forces, but the central bank intervenes when the rate moves too far from a desired level. Singapore's Monetary Authority (MAS) allows the Singapore dollar to move within a band of plus or minus 3 per cent, intervening to keep it within that range.

Q5: What are the main disadvantages of a fixed exchange rate system? The main disadvantages are: (1) high opportunity cost - defending the rate requires large foreign currency reserves that could be used elsewhere; (2) limited monetary policy - the obligation to defend the rate constrains the central bank's ability to use interest rates freely; (3) reduced currency liquidity - holding large reserves ties up capital that might otherwise be available to private investors.

Stay well,

Related Topics:

IB Economics Hub Page your IB Economics daily guide

IB Economics The Global Economy Hub Page access Fixed Exchange Rates here as well as the rest of the module 4

IB Economics Activity book Page Module 4 The Global Economy Unit 4.7 for Fixed Exchange Rates exam practice, activities, model answers and IB Economics Marking schemes

IB Economics the current account and balance of payments Page, revise this topic when discussing the consequences of overvalued currencies on the current account

IB Economics Diagrams Page Check Unit 27 for All Fixed Exchange Rates diagrams with explanations

IB Economics Monetary Policy Hub Page for discussing the constraints fixed rates place on interest rate decisions

IB Economics Inflation Hub Page → when discussing imported inflation from undervalued currencies

IB economics Calculations Book make sure you check unit 24 for Fixed Exchange Rates calculations exercises, IB model answers, and IB marking schemes

Read Next: IB Economics Balance of Payments Current Accounts Page

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