Exchange rates

Welcome to the Exchange Rates Chapter!

Hello future economist! This chapter is all about understanding the price of money—specifically, how the value of one country's currency is set against another's. Why is this important? Because the exchange rate affects everything: the cost of your imported sneakers, how many tourists visit your country, and whether your economy is competitive globally. Don't worry if this seems tricky at first; we will break down the foreign exchange market using familiar tools: supply and demand!

Key Syllabus Focus (AS & A Level):

• Defining the exchange rate and different systems.
• Using supply and demand to determine floating exchange rates.
• Analyzing the impact of rate changes on the macroeconomy (AD/AS).
• Evaluating the effects of changes using the Marshall-Lerner condition and the J-Curve (A Level).

1. Defining the Exchange Rate and Core Terminology

1.1 What is an Exchange Rate? (6.4.1)

The exchange rate is simply the price of one currency in terms of another currency. It tells you how much of Currency A you need to buy one unit of Currency B.

Example: If the exchange rate between the UK Pound (£) and the US Dollar ($) is $1.30 = £1, it means you need $1.30 to buy one British Pound.

1.2 Nominal vs. Real Exchange Rates (A Level Extension 11.2.1)

The distinction between nominal and real rates is important for deeper analysis (especially in A Level):

• Nominal Exchange Rate: This is the exchange rate you see quoted every day. It is the price of one currency in terms of another, unadjusted for inflation. ($1.30 = £1)
• Real Exchange Rate: This rate adjusts the nominal rate for the differences in price levels (inflation) between the two countries. It represents the relative buying power of the currency.

Quick Analogy: The nominal rate is like the price tag on a book; the real rate is how many chapters of content you actually get compared to a book from another country after accounting for printing costs (inflation).

2. The Determination of Floating Exchange Rates (6.4.2 & 6.4.4)

A floating exchange rate is determined purely by the market forces of demand and supply for that currency in the foreign exchange market (Forex).

2.1 Demand for a Currency

Demand for a country's currency (e.g., the US Dollar, USD) comes from anyone needing to buy goods, services, or assets in that country.

Key Factors Increasing Demand (Shift D right):

1. Exports (X): When foreigners buy US goods (e.g., American aircraft), they must first demand USD to pay for them.
2. Foreign Direct Investment (FDI) Inflow: When foreign firms build factories or buy companies in the US, they need USD.
3. Portfolio Investment Inflow: When foreigners buy US financial assets (e.g., Treasury bonds or shares), they demand USD.
4. Higher Interest Rates (Relative): If US interest rates are higher than in Europe, foreign investors shift their money to the US to earn a better return, increasing demand for USD (known as "hot money").
5. Speculation: If speculators expect the USD to rise in the future, they buy it now, increasing current demand.

2.2 Supply of a Currency

The supply of a country's currency (e.g., the USD) comes from locals needing to exchange their currency to buy foreign goods, services, or assets.

Key Factors Increasing Supply (Shift S right):

1. Imports (M): When US residents buy foreign goods (e.g., German cars), they must supply USD to buy Euros to pay the manufacturer.
2. FDI Outflow: When US firms invest abroad (e.g., building a factory in Mexico), they supply USD to get Pesos.
3. Portfolio Investment Outflow: When US residents buy foreign assets, they supply USD.
4. Lower Interest Rates (Relative): If US rates fall relative to other countries, investors move their money out, increasing the supply of USD on the market.
5. Speculation: If speculators expect the USD to fall, they sell it now, increasing current supply.

2.3 Appreciation and Depreciation (6.4.3)

When an exchange rate changes in a floating system, we use specific terms:

• Appreciation: This occurs when the value of the currency rises relative to another currency, caused by market forces (Demand increases or Supply decreases). The currency can buy more foreign currency.
• Depreciation: This occurs when the value of the currency falls relative to another currency, caused by market forces (Demand decreases or Supply increases). The currency can buy less foreign currency.

Key Takeaway for Floating Rates: In a floating system, changes are natural movements resulting from shifts in international transactions (trade and capital flows).

3. Fixed and Managed Exchange Rate Systems (A Level Extension 11.2.2 & 11.2.3)

Not all currencies float freely.

3.1 Fixed Exchange Rate Systems

In a fixed exchange rate system, the government (or Central Bank) legally sets its currency's value against another currency (the anchor currency, often USD or Euro) or a basket of currencies.

• Intervention: If market forces push the rate above the fixed target, the Central Bank sells its currency (increasing supply) or buys foreign reserves. If market forces push the rate below the fixed target, the Central Bank buys its currency (increasing demand) using its foreign reserves.
• Devaluation: This is the official lowering of the fixed value by the government.
• Revaluation: This is the official raising of the fixed value by the government.

3.2 Managed Float System

A managed float is a hybrid system. The currency is primarily determined by supply and demand, but the Central Bank intervenes occasionally to prevent sharp or undesirable fluctuations.

Example: If the currency is depreciating too fast, the Central Bank might step in and use some reserves to buy its own currency, limiting the speed of the fall.

AVOID COMMON MISTAKES!
You must use the correct terminology:
Floating System: Appreciation / Depreciation.
Fixed System: Revaluation / Devaluation.

4. Impact of Exchange Rate Changes on the Macroeconomy (6.4.5)

When an exchange rate changes, it significantly affects a country's exports (X) and imports (M), which are key components of Aggregate Demand (AD).

Step-by-Step Analysis of a Depreciation (or Devaluation)

Imagine the Pound (£) depreciates against the Euro (€). The rate moves from €1.20 = £1 to €1.10 = £1.

1. Impact on Price of Trade:
   • Exports (X): UK goods are now cheaper for Eurozone consumers. (A UK item costing £10 now costs them only €11 instead of €12).
   • Imports (M): Eurozone goods are now more expensive for UK consumers. (A Eurozone item costing €12 now costs UK consumers £10.90 instead of £10.00).
2. Impact on Net Exports (X–M):
   • Assuming demand for imports and exports is relatively price elastic, X will rise and M will fall.
   • Net Exports \((X-M)\) will increase.
3. Impact on AD (AD = C + I + G + (X–M)):
   • Since \((X-M)\) is a component of AD, an increase in net exports causes Aggregate Demand to shift to the right.
4. Impact on Domestic Economy (using AD/AS model):
   • Real Output (Y): Increases (Economic Growth).
   • Employment: Increases, as firms must hire more workers to meet the higher demand for exports and the rise in domestic production (import substitution).
   • Price Level (P): Rises (Inflationary pressure). This is due to higher AD and potentially higher costs from more expensive imports (imported raw materials cost more, leading to cost-push inflation).

The reverse applies for an Appreciation (or Revaluation): AD shifts left, causing lower output, lower employment, and lower prices (deflationary pressure).

5. Advanced Analysis: When Does Depreciation Work? (A Level 11.2.5)

A central question for governments is: Will depreciating the currency actually improve the trade balance? The answer depends on price elasticity of demand (PED).

5.1 The Marshall-Lerner Condition

The Marshall-Lerner Condition (MLC) states that a depreciation (or devaluation) will only improve the current account balance (increase net exports) if the sum of the Price Elasticities of Demand for exports (\(PED_X\)) and imports (\(PED_M\)) is greater than one (in absolute terms).

Condition for improvement: \(|PED_X| + |PED_M| > 1\)

• If \((|PED_X| + |PED_M|) > 1\): The depreciation is successful. The resulting large increase in export volume and decrease in import volume outweigh the adverse price effect.
• If \((|PED_X| + |PED_M|) < 1\): The depreciation fails. The price of exports falls and import prices rise, but volumes barely change, leading to a worse trade balance (a small volume change cannot offset the large price change).

5.2 The J-Curve Effect

In the real world, the trade balance often gets worse immediately after a depreciation before it gets better. This pattern is known as the J-Curve Effect.

Step-by-Step J-Curve:

1. Initial Phase (Short Run): When the currency first depreciates, the volume of exports and imports remains largely unchanged because it takes time for consumers and firms to adjust their purchasing habits (demand is inelastic in the short run). However, the price effect is instantaneous: imports are immediately more expensive. This causes the Current Account Balance to worsen. (This is the bottom dip of the 'J'.)
2. Second Phase (Longer Run): As time passes, consumers recognize the price changes. Foreign buyers switch to cheaper domestic exports (X rises) and domestic consumers switch away from dearer imports (M falls). Demand becomes more elastic, and \((|PED_X| + |PED_M|) > 1\). The current account balance eventually improves. (This is the upward slope of the 'J'.)

Think of it like this: If the price of imported cars goes up, you don't instantly stop buying your expensive foreign car, but next year, when you replace it, you might choose a locally produced model. This time lag creates the J-Curve.

Summary Table: Comparing Exchange Rate Systems

Final Key Takeaway: Exchange rates are critical for macroeconomic performance. A key evaluation point is that exchange rate changes only successfully improve the trade balance if demand is elastic (MLC) and if you allow sufficient time for the J-Curve effect to pass.