Is it permissible to replace an old car—whose installments are still being paid—with a new car from the same dealership after the old one is appraised at market value and the difference is paid, or does this fall under the ruling of Bay’ al-’Inah (a form of usury)?

The described scenario—selling an old car for a new car with a payment of the difference—is permissible because cars are not usurious commodities. The Permanent Committee has issued a fatwa (definition) allowing this, and Ibn Uthaymeen stated that disparity and deferment are permissible for non-usurious commodities.