What is the ruling on exchanging Saudi Riyals for Sudanese Pounds while benefiting from the price difference between cash deposits and bank transfers resulting from the liquidity problem in Sudanese banks?

This transaction is considered a currency exchange (sarf), and it requires immediate possession (taqabud) at the same sitting (majlis), even if constructively, to avoid the usury of delay (riba al-nasi'ah), which is unanimously prohibited. Constructive possession is achieved when the client's agent in Sudan receives the Sudanese Pounds at the time of the contract assembly between the questioner and his client in Saudi Arabia. If this occurs, then there is no harm, and the Saudi Riyals become the property of the questioner. If the questioner transfers the Riyals to his account in Sudan through higher-level merchants, and then his agent there withdraws and exchanges them for Sudanese Pounds, there is no harm in that, even if the exchange rate is higher than what they initially agreed upon in Saudi Arabia.