Foreign-exchange risk, also called currency risk or FX risk, is the possibility that exchange-rate movements reduce an investment’s value or worsen a cash flow when measured in a chosen currency. A profitable foreign asset can produce a loss in the investor’s spending currency. The reference currency matters: the same exchange-rate move helps a foreign-currency receiver and hurts a foreign-currency payer in opposite directions.
This is a source of market risk, rather than something that requires speculative currency trading. The SEC’s international-investing guide identifies currency movements as one reason an international investment’s return can rise or fall.
Name the currency before measuring the return
Take a USD-based investor holding an asset valued in euros. Throughout this example, means USD per EUR: multiply a euro amount by to obtain dollars. A fall in means that each euro buys fewer dollars.
Let be the euro value of the holding and its dollar value. With no distributions, external cash flows, costs or hedge,
Suppose the holding begins at EUR 100, with USD per EUR. Its opening value is USD 120. At the end of the period, : the euro has lost 12.5% of its dollar value. These are fictional scenario inputs, not market observations.
| Same closing exchange rate: 1.05 USD per EUR | Closing euro value | Closing dollar value | USD return |
|---|---|---|---|
| Local asset price unchanged | EUR 100 | USD 105 | −12.5% |
| Local asset gains 10% | EUR 110 | USD 115.50 | −3.75% |
A euro gain does not automatically mean a dollar gain. For the second row, define the local return and the currency return . The exact conversion is
Adding 10% and −12.5% gives −2.5%, which misses the interaction term of −1.25 percentage points. Percentage returns multiply through their growth factors; simple addition is an approximation.
Original synthetic arithmetic bridge, not an observed intraperiod path. All exchange rates are USD per EUR. The intermediate USD 132 holds the starting exchange rate fixed for attribution. Costs, distributions and hedging are excluded.
The bridge reprices the asset at the starting exchange rate, adding USD 12, then applies the exchange-rate fall to the final EUR 110, subtracting USD 16.50. That is an arithmetic decomposition, not a claim about the order of market moves within the period.
If a data feed instead quotes EUR per USD, take the reciprocal before using this formula. Reversing a quote changes the percentage-return denominator; it does not simply reverse the sign. The FX lesson, available with a free signed-in account, develops quotation units and bid–ask conversions.
A currency exposure can sit in several places
For businesses, the exposure is broader than translating an investment balance. A useful distinction is:
| Exposure | What an exchange-rate move changes |
|---|---|
| Transaction | The home-currency amount received or paid on a foreign-currency receivable or payable. |
| Translation | Reported amounts when foreign operations’ financial statements are converted into a reporting currency. A translation movement need not be a cash payment; its treatment depends on the applicable accounting rules. |
| Economic or operating | Future revenues, costs and competitiveness, including effects on customers and competitors. |
This classification follows Papaioannou’s IMF working paper, §II. For example, a domestic manufacturer can have currency sensitivity through imported inputs or foreign competition even when it invoices customers in its home currency. This is a currency channel within broader business risk.
A security’s trading currency alone therefore does not identify its full economic currency exposure. For the same reason, requiring home-currency payment can change direct transaction exposure while leaving commercial consequences. The International Trade Administration notes that insisting on USD payment may affect export competitiveness or a buyer’s ability to pay.
Match a hedge to an amount and a date
A forward contract can fix today the exchange rate for a specified future currency exchange. A USD-based exporter expecting a known euro receipt can sell that euro amount forward; a business owing euros can buy euros forward. Whether the hedge later beats the unhedged spot conversion is separate from whether it supplied the desired cash-flow certainty.
The amount matters. A fixed forward can cover a known euro payment, but the future euro value of a risky asset is uncertain. Hedging its opening value leaves a mismatch if that asset’s euro value changes. Matching receipts and payments in the same currency can also reduce net exposure, provided their amounts and timing align. Neither approach automatically removes counterparty exposure, costs or possible funding liquidity risk.
For a portfolio, the risk question is about the combined asset and currency returns and how they move together. A currency hedge changes that combination; it does not establish that every measure of total portfolio risk must fall.
Sources
- Elton, Gruber, Brown and Goetzmann, Modern Portfolio Theory and Investment Analysis, 9th ed., Wiley, 2014, Chapter 12, pp. 259–261 and 270: exact foreign-investment return composition and the limitation of hedging an unknown terminal asset value with a fixed currency amount. The numerical bridge here is original and synthetic.
- SEC Investor.gov: International Investing: currency movements can increase or reduce international-investment returns.
- International Trade Administration: Foreign Exchange Risk: contractual currency receipts, forward hedging and the commercial consequences of invoicing choices.
- Michael Papaioannou, Exchange Rate Risk Measurement and Management: Issues and Approaches for Firms, IMF Working Paper 06/255, 2006, §II, printed p. 4: transaction, translation and economic exposures. This is an author’s working paper, not a statement of current accounting rules.