If the currency exchange rates are unstable and there is an expectation of an increase in the value of the foreign currency against the local currency, it is permissible for you to estimate the value of the risk and include it in the total price before selling, as both parties have the option to accept or reject the price. If the buyer accepts the price, then the sale is valid.
The problem arises for those who buy on a long-term credit and the currency exchange rates change. Therefore, there are the following scenarios:
The first scenario is that the buyer has imported the goods before the currency exchange rates changed and sold them before the change occurred, but they still have some money left. In this case, they are not entitled to claim the difference because there is no harm to them. They paid the same price they sold it for and any future changes will be taken into account for future purchases, not for what they purchased during the stable currency period. An example of this is:
A merchant imported a car when the exchange rate was 15 pounds per dollar, and sold it on installment based on that rate. They are not entitled to increase the value or claim the difference because they have benefited from the original price.
However, if the merchant did not sell the car until the exchange rate increased to, for example, 20 pounds per dollar, they are entitled to change the price based on the new exchange rate because they will import new goods at the new rate, not at the old rate.
The second scenario is when a currency exchange rate change occurs before the delivery and before the completion of the price. An example of this is:
For example, if someone buys an apartment and agrees on a certain price, with delivery after several years and payment of the price in installments over these years, and then a currency exchange rate change occurs, this case requires our ijtihad, and what we mentioned in the previous fatwa applies to it. The price must be adjusted based on the new exchange rate; otherwise, it would be unjust and oppressive to the seller.
The third scenario is when the agreement between the parties is based on a debt that is only due under certain conditions. An example of this is:
The dowry (mahr) is an example of this scenario. It is customary to divide the dowry into an upfront payment and a deferred payment, while some people make the entire dowry deferred. The couple may live for many years and a significant exchange rate change may occur. In this case, it would be unjust to pay the woman the agreed-upon dowry amount, which has already been spent due to the change in the exchange rate. In some countries like Syria, Yemen, and Lebanon, the local currency may have depreciated significantly and is worth very little. In this case, the dowry should be estimated based on the value of gold at the time of the contract, and the equivalent amount at the immediate time should be paid.
Fatwa by Dr. Khālid Naṣr