What is the ruling on the bank taking a 1% commission for processing an installment purchase from a store?

Purchasing in installments from stores through a bank can take four forms:

1. Prohibited Usurious Loan (Qard Ribawi): If the bank pays the price of the commodity to the merchant immediately, and then recovers it from the client in installments with an increment, this is considered usury (riba), even if the increment is small. This is not considered an administrative fee unless it represents the actual cost and is a fixed amount.

2. Prohibited Guarantee: If the client pays the price in installments to the merchant, and the bank takes a percentage in exchange for guaranteeing the client, this is prohibited. This is because a guarantee (daman) is a gratuitous contract for which it is not permissible to take a fee, and it leads to usury if the client defaults.

3. Permissible Murabaha Sale: If the bank purchases the commodity for itself and then sells it to the client for a profit, this is permissible (Murabaha sale). It is permissible to take additional fees for the Murabaha procedures as there is no loan involved.

4. Prohibited Organized Tawarruq: If the bank provides the client with funds through "Tawarruq" to purchase the commodity, and the Tawarruq is organized, where the bank sells the commodity to the client and then acts as their agent in selling it to a third party, this is prohibited. However, if the client takes possession of the commodity and sells it themselves, it is permissible.