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The Foreign
Exchange Market

Understand how currencies are traded, what determines exchange rates, and how shifts in supply and demand affect the value of a nation's currency.

AP Macroeconomics

What Is the Foreign Exchange Market?

The foreign exchange market (forex market) is a global marketplace where national currencies are bought and sold. It is the largest financial market in the world, with over $7.5 trillion traded daily.

Exchange Rate
The price of one currency expressed in terms of another currency
Forex Market
Decentralized market where governments, banks, firms, and individuals trade currencies

Why Are Currencies Traded?

People and institutions demand foreign currencies for several key reasons. Every international transaction ultimately requires a currency exchange.

1
International trade: A U.S. firm importing Japanese cars needs yen to pay the Japanese manufacturer.
2
Foreign investment: A British investor buying U.S. Treasury bonds needs dollars.
3
Tourism: A German tourist visiting Mexico needs pesos for local purchases.
4
Speculation: Traders buy currencies they expect to appreciate in value.

Supply and Demand for Currency

The exchange rate is determined just like any other price: by the interaction of supply and demand in the currency market.

Demand for $
Foreigners who want to buy U.S. goods, invest in the U.S., or travel to the U.S. demand dollars
Supply of $
Americans who want to buy foreign goods, invest abroad, or travel overseas supply dollars (by exchanging them for foreign currency)

The Forex Market Graph

Quantity of Dollars Price of $ (in foreign currency)
\(D_{\$}\)
\(S_{\$}\)
\(E\)
\(e^*\)
\(Q^*\)

Appreciation vs. Depreciation

Appreciation
A currency increases in value relative to another. It now buys more foreign currency. Example: \(1\,\text{USD} = 100\,\text{JPY}\) rises to \(1\,\text{USD} = 120\,\text{JPY}\).
Depreciation
A currency decreases in value relative to another. It now buys less foreign currency. Example: \(1\,\text{USD} = 100\,\text{JPY}\) falls to \(1\,\text{USD} = 80\,\text{JPY}\).

Floating vs. Fixed Exchange Rates

Floating (Flexible) Fixed (Pegged)
Determined by Supply and demand in the market Government or central bank
Rate changes Continuously, via market forces Only when government adjusts the peg
Government role Minimal intervention Must buy/sell reserves to maintain rate
Examples U.S. dollar, euro, yen Hong Kong dollar, some Middle East currencies
AP Exam focus Primary model tested Occasionally tested

Determinants of Exchange Rates

Several factors shift the supply and demand curves for a currency, changing its exchange rate:

Interest Rates
Higher domestic rates attract foreign investment, increasing demand for the currency
Inflation Rates
Higher inflation makes goods expensive, reducing foreign demand for the currency
Income / GDP
Higher domestic income increases imports, raising the supply of domestic currency

How to Analyze Forex Changes

1
Identify the event: What economic change occurred? (e.g., interest rates rise in the U.S.)
2
Determine the affected curve: Does the event shift the demand for or supply of the currency?
3
Shift the correct curve: Draw the shift (increase = right, decrease = left) on the forex graph.
4
Find the new equilibrium: Read the new exchange rate from the graph.
5
State the result: The currency appreciated or depreciated. Explain the effect on trade.

Example 1: Rising U.S. Interest Rates

Scenario: The Federal Reserve raises interest rates. How does this affect the dollar in the forex market?

Quantity of Dollars Price of $ (yen/dollar)
\(D_1\)
\(D_2\)
\(S_{\$}\)
\(E_1\)
\(E_2\)
\(e_2\)
\(e_1\)

Example 2: Rising U.S. Inflation

Scenario: The U.S. experiences higher inflation than its trading partners. What happens to the dollar?

Quantity of Dollars Price of $ (euros/dollar)
\(D_1\)
\(D_2\)
\(S_{\$}\)
\(E_1\)
\(E_2\)
\(e_1\)
\(e_2\)

Example 3: Americans Demand More Imports

Scenario: U.S. consumers develop a strong preference for European cars. What happens to the dollar?

Quantity of Dollars Price of $ (euros/dollar)
\(D_{\$}\)
\(S_1\)
\(S_2\)
\(E_1\)
\(E_2\)
\(e_1\)
\(e_2\)

Exchange Rates and Net Exports

Exchange rate changes directly affect a country's net exports (\(\text{NX} = \text{Exports} - \text{Imports}\)), linking the forex market to aggregate demand.

Dollar Appreciates
U.S. exports more expensive, imports cheaper: \(NX\) decreases, \(AD\) shifts left
Dollar Depreciates
U.S. exports cheaper, imports more expensive: \(NX\) increases, \(AD\) shifts right

The Interest Rate Connection

On the AP exam, you must connect changes in monetary policy to exchange rates. Here is the complete causal chain:

Money Supply changes Interest Rates change Capital Flows shift Exchange Rate changes
\(NX \rightarrow AD\)

Common Mistakes on Forex Questions

✕ Confusing Supply and Demand
When Americans buy imports, they supply dollars (not demand them). Demand for dollars comes from foreigners wanting U.S. goods or assets.
✕ Forgetting the Inverse
If the dollar appreciates, the other currency must depreciate. Students often forget to state both sides.
✕ Wrong NX Effect
A stronger dollar makes exports more expensive (\(NX\) falls), not cheaper. Think: strong dollar = expensive American goods abroad.

Summary: Shifts in the Forex Market

Event Curve Shift Dollar Effect
U.S. interest rates rise \(D_{\$}\) increases (right) Appreciates
U.S. inflation rises \(D_{\$}\) decreases (left) Depreciates
U.S. income rises \(S_{\$}\) increases (right) Depreciates
Foreign demand for U.S. goods rises \(D_{\$}\) increases (right) Appreciates
Americans prefer foreign goods \(S_{\$}\) increases (right) Depreciates
Foreign interest rates rise \(S_{\$}\) increases (right) Depreciates

Question 1 of 5

If the Federal Reserve raises the federal funds rate, what happens to the value of the U.S. dollar in the foreign exchange market?

Question 2 of 5

If U.S. consumers develop a strong preference for Japanese electronics, what happens in the market for the Japanese yen?

Question 3 of 5

If the U.S. dollar depreciates against the euro, which of the following is most likely to occur?

Question 4 of 5

In the foreign exchange market for the U.S. dollar, which of the following would cause the supply of dollars to increase?

Question 5 of 5

Based on the scenario above, what is the most likely outcome in the foreign exchange market?