Transaction risk is the probability that a party to a business transaction will lose money due to an adverse change in the relevant foreign exchange rate. For example, a company in Europe agrees to pay in U.S. dollars for production equipment that is sold by a firm in the United States, with payment due in 30 days. If the exchange rate for Euros weakens during the intervening 30 days, the buyer will have to spend more Euros to buy the dollars it needs to pay the seller. The parties to such a transaction can use hedging techniques to reduce or eliminate transaction risk.
Transaction risk tends to increase when there is a long period of time between entering into a contract and settling it, since there is more time in which the relevant exchange rate can vary.