What is the ruling on purchasing a car in installments, with installments reaching 75% of its value over 5 years, where the selling party first buys the car then resells it in installments, and a power of attorney for the car in their favor is stipulated without mentioning it in the contract?

It is permissible to purchase a car by installments or through murabaha (cost-plus financing) for a prospective buyer, provided that the promise is not binding on both parties, that the company owns and possesses the car before selling it, that the sale is made to the interested buyer, and that no penalty is stipulated for late payment of installments.

It is permissible for the company to charge a fee for inquiry, provided it covers actual costs.

There is no harm in restricting the buyer from selling the car until they have paid what is due, provided that the ownership of the car is transferred to the buyer. This falls under the category of mortgaging the sold item for its price.

Regarding the company's proxy: If the intention is for the company to give the buyer a proxy to enable them to use the car while the company retains the registration document (istimarah) and provides the buyer with a document proving their ownership of the car, then there is no harm. However, if the company does not provide the buyer with a document proving their ownership, then this is not permissible.