Fiqh al-Sarf wal-Sila — Currency Exchange in Islamic Law: The Sarf Contract (Money for Money), the Two Types of Riba Relevant to Exchange (Riba al-Fadl and Riba al-Nasi'a), the Six Ribawi Commodities, How Spot vs Deferred Settlement Determines Permissibility, and Modern Islamic Bank Foreign Exchange

Fiqh al-Sarf wal-Sila (فِقهُ الصَّرفِ وَالصِّيلَة — Jurisprudence of Currency Exchange; *sarf*: exchange of money for money, currency exchange; from *s-r-f*: to turn away, to exchange, to spend; *sila*: connection, linking [used in some schools for reciprocal currency transactions]; the ribawi commodities: the foundational hadith on sarf and riba: 'Gold for gold, silver for silver, wheat for wheat, barley for barley, dates for dates, salt for salt — like for like, equal for equal, hand to hand [yadan bi-yadin]. Whoever increases or asks for an increase has engaged in riba, the giver and taker alike' [Sahih Muslim, narrated by Ubada ibn al-Samit]; the six ribawi commodities: gold, silver, wheat, barley, dates, salt; the two types of riba in exchange: [1] riba al-fadl [excess riba]: exchanging unequal quantities of the same commodity [e.g., 100g gold for 110g gold]; prohibited even if hand-to-hand; the rationale: like items must be exchanged for exact equivalents; [2] riba al-nasi'a [deferred riba, also called riba al-jahiliyya]: exchanging ribawi items on credit [deferred payment]; exchanging even equal quantities of the same commodity on deferred basis is riba al-nasi'a; the sarf rules: the sarf contract [money-for-money exchange] has its own rules derived from the ribawi commodity framework: [1] same currency [e.g., gold for gold]: must be equal quantity AND hand-to-hand [no deferred settlement]; [2] different currencies from the same genus [in classical fiqh — two types of gold coinage, or dirham vs dinar]: opinions vary; most say if different enough in custom, they function as different currency types; [3] modern paper currencies: the Hanafi position extended to fiat currencies: paper money of the same issuer [e.g., one dollar for one dollar] must be equal; different currencies [USD for EUR] can be exchanged in unequal amounts [spot rate] BUT must settle hand-to-hand [spot]; AAOIFI Standard 1 and 2 on currency exchange: [1] currencies of the same issuer: must exchange at par, hand-to-hand; [2] currencies of different issuers: can exchange at market rate but must settle spot [no deferred settlement]; the spot requirement is the critical rule: even if exchange rates differ, the delivery must be simultaneous [T+0] or at most T+2 [the OIC Fiqh Academy has debated whether T+2 standard foreign exchange settlement satisfies the 'hand-to-hand' requirement — majority position: T+2 is permissible given the nature of modern banking systems and the synchronization of settlement]; the modern Islamic bank forex: commodity murabahah used for hedging; currency forwards are problematic [deferred settlement]; Islamic swaps use alternative structures; the controversy over currency derivatives: forward contracts [agreeing to exchange currencies at a future date] are prohibited under strict sarf analysis because they violate the hand-to-hand requirement; Islamic hedging seeks alternative structures to manage currency risk without prohibited deferred currency exchange) is the Islamic framework for money-exchange transactions.