The ruling on selling dollars for riyals on a deferred basis

Question:
Honorable Shaykh, may Allah grant you success. A man asks about buying one thousand dollars for two thousand dollars on a deferred basis, with the payment between them to be in Saudi riyals. Is this permissible?

Answer:
No, this is not permissible under any circumstances. Selling currency for currency on a deferred basis is not permissible, whether the currencies are of the same type or different types. This is riba al-nasi'ah (usury of deferment). If the currency is of the same type, it combines riba al-nasi'ah and riba al-fadl (usury of excess in a like-for-like exchange). If he buys one thousand dollars for one thousand five hundred dollars on a deferred basis, this is riba al-fadl and riba al-nasi'ah. If he buys one thousand dollars for fifty thousand Saudi riyals and defers the payment, this is riba al-nasi'ah. The door of ignorance is open here, but it is riba al-nasi'ah. This deferral is not permissible.