Currency hedging protects against exchange rate fluctuations using forwards, futures, options, and swaps. Forward contracts lock in exchange rates using covered interest rate parity. Option-based hedges protect against adverse moves while preserving upside. The choice between hedging tools depends on cost, accounting treatment, and risk tolerance.
You know from covered interest rate parity (CIP) that forward exchange rates are not forecasts of the future spot rate — they are prices derived from the no-arbitrage relationship between spot rates and interest rate differentials. Specifically, the forward rate F = S × (1 + r_d)/(1 + r_f), where S is the current spot rate and r_d, r_f are domestic and foreign interest rates. This pricing relationship is the foundation of currency hedging: because you can lock in a future exchange rate through a forward contract at a known, arbitrage-free price, you can eliminate currency exposure from a future cash flow.
Consider a US exporter expecting to receive €1 million in three months. If the euro depreciates by the time payment arrives, the dollar value of that receivable shrinks. A currency forward solves this: enter a forward contract to sell €1 million in three months at today's three-month forward rate. Whatever the spot rate turns out to be at settlement, the exporter receives the locked-in forward rate. The hedge converts uncertain future foreign-currency cash flows into a certain domestic-currency amount — the uncertainty is not reduced in the world, but it is transferred to the counterparty. The cost of this certainty is embedded in the forward-spot differential, which CIP tells you equals the interest rate differential.
Currency options offer a different risk profile. A put option on euros gives the holder the right — but not the obligation — to sell euros at the strike price. If the euro falls below the strike, the put pays off; if the euro stays high, the holder simply lets the option expire and benefits from the favorable spot rate. This asymmetric payoff is the key distinction from a forward: the forward eliminates all exchange rate risk (good and bad), while the put eliminates only downside risk. The price of this asymmetry is the option premium, paid upfront regardless of whether the option is exercised. Firms with uncertain foreign-currency cash flows (they might receive €1 million, or maybe less, depending on sales) often prefer options over forwards for this reason.
The choice among hedging instruments — forward, futures, option, swap, or a combination — depends on several practical factors. Forwards are customizable in amount and maturity (OTC contracts) but carry counterparty credit risk. Currency futures are exchange-traded and thus standardized and marked to market daily, eliminating counterparty risk but introducing basis risk if the maturity and amount don't match perfectly. Cross-currency swaps exchange principal and interest cash flows in two currencies and are suited for longer-horizon exposures like foreign-currency debt. Accounting treatment also matters: hedges that qualify for hedge accounting under IFRS or US GAAP allow gains and losses to offset the hedged item in the income statement rather than creating earnings volatility — so treasurers often structure hedges to satisfy accounting as much as to minimize risk economically.