Spot and forward exchange rates: how FX pricing works across time horizons

The spot exchange rate and the forward exchange rate are the two foundational prices in currency markets. The spot rate is the price for exchanging two currencies today—technically within two business days. The forward rate is the price agreed now for an exchange to take place on a specified future date. The relationship between the two is determined by interest rates, not by any forecast of where the currency will trade in the future.

What spot and forward exchange rates are

The spot rate is the most familiar FX price. When a news website quotes EUR/USD at 1.0850, it is showing the spot rate: the number of US dollars required to buy one euro for delivery in two business days. The two-day settlement convention (T+2) is a legacy of the time required to transfer funds across banking systems; it has persisted into modern electronic markets.

A forward exchange rate is a contractually agreed price for exchanging two currencies on a future date—one month, three months, one year, or any agreed tenor. The forward contract locks in the rate today; the actual exchange of currencies takes place on the agreed future date. Forward contracts are primarily used by corporations to hedge known future currency exposures (a UK company expecting to receive USD 10 million in 90 days might sell USD forward to lock in the sterling proceeds) and by financial institutions to manage currency risk in international portfolios.

How the forward rate is determined

The forward rate is not a forecast. It is a no-arbitrage price derived from the spot rate and the interest rate differential between the two currencies. This relationship is formalised in the covered interest rate parity (CIP) theorem: the forward rate must equal the spot rate adjusted for the difference in risk-free interest rates between the two currencies over the forward period.

The intuition is straightforward. Suppose the EUR risk-free rate is 2% per year and the USD risk-free rate is 5% per year. An investor with EUR 1,000,000 can either invest in euros at 2% or convert to dollars at the spot rate, invest at 5%, and convert back at the end of the year. For there to be no arbitrage profit, the forward rate must reflect the 3% interest rate differential: the USD must trade at a 3% forward discount to the EUR (meaning the EUR is more expensive in forward terms than at spot). If the forward rate deviated from this relationship, traders could earn risk-free profits by borrowing in one currency, investing in the other, and hedging the exchange rate via the forward market.

In practice, covered interest rate parity holds closely in the interbank market for major currency pairs, because the arbitrage trades that enforce it are large and fast. Minor deviations can persist for short periods when funding constraints prevent arbitrageurs from acting, but they are typically small and short-lived.

What the evidence shows

Empirical research on forward rates as predictors of future spot rates has found that they are poor forecasters. Uncovered interest rate parity—the hypothesis that the forward rate reflects the expected future spot rate—fails consistently in empirical data. High-interest-rate currencies tend to appreciate rather than depreciate, as uncovered parity would predict. This systematic failure is the basis for the currency carry trade, which exploits the tendency of high-rate currencies to outperform despite the forward rate implying the opposite.

The distinction matters for investors: the forward rate tells you the no-arbitrage cost of locking in a future exchange rate; it does not tell you where the exchange rate is likely to be at that date. Investors who interpret a forward discount as a prediction of future depreciation are confusing a pricing mechanism with a forecast.

Limitations and trade-offs

Forward contracts require a counterparty, and the creditworthiness of that counterparty matters. In the interbank market, forward contracts are OTC agreements with no central clearing, meaning that if a counterparty defaults before the settlement date, the non-defaulting party may face a replacement cost at adverse rates. This credit risk is managed through master agreements (ISDA) and, increasingly, through central clearing for standardised tenors.

Retail investors cannot easily access the interbank forward market directly. They typically access forward-equivalent pricing through currency futures (exchange-traded forwards with standardised contract sizes and maturities), currency-hedged ETFs (which embed rolling forward hedges within the fund), or through a broker offering FX forward contracts with higher minimum sizes and wider spreads than the interbank market.

Spot and forward rates in pfolio

Forward pricing is the mechanism behind the currency hedging embedded in currency-hedged ETFs available in pfolio's investable universe. When a currency-hedged ETF rolls its monthly forward contracts, it does so at the prevailing forward rate, which reflects the current interest rate differential between the fund's base currency and the currency being hedged. The FX exposure across a pfolio portfolio—both hedged and unhedged—is visible in pfolio Insights. Currency assets available for direct allocation are listed in the Assets section.

Related articles

• How foreign exchange markets work: structure, participants, and price discovery
• Currency-hedged ETFs: how they work and when the hedge is worth paying for
• The currency carry trade: borrowing low to invest high and the risks involved
• Futures explained: how futures contracts work and why they matter for commodity and currency exposure