What is the ruling on selling an item for one price denominated in one currency contingent upon receiving payment in a different currency?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The sale is invalid if the contract stipulates that the payment, agreed upon in one denomination (e.g., gold), must be exchanged for another (e.g., dirhams) at a set rate. Ahmad stated this invalidity arises because it involves stipulating an exchange (*saraf*), which itself is a sale contract, resulting in two sales within one transaction (*bay'atayn fi bay'ah*). This is supported by the Hadith of the Prophet (peace be upon him) prohibiting two sales in one sale, narrated by Abu Hurayrah (Tirmidhi, Hassan Sahih) and Abdullah ibn Amr.
Supporting text
This invalidity extends to similar conditions, such as stipulating an exchange of properties, a rental agreement, or a marriage contract contingent upon the primary sale. Ibn Mas'ud, Abu Hanifa, Shafi'i, and the majority hold this constitutes two transactions involving Riba (usury). Malik permitted it, stating that he disregards the invalid wording if the substance is known and permissible, treating it as a sale for the specified cash equivalent.