What is the ruling on leasing an uncovered bank credit of 100 million for one year for 5% of its value, knowing that the lessee will use it to obtain investment facilities, and does the ruling apply to the intermediary who completed the contract?

It is not permissible to lease a letter of credit for a fee, because it involves taking a fee for a mere guarantee, which is prohibited by Islamic law according to the majority of scholars. Sponsorship (kafalah) is a contract of donation and assistance, and it is not permissible to take compensation for it, because it resembles a loan that brings a benefit. It is also not permissible to take a fee for a letter of guarantee. If a transaction is impermissible, then mediation in it and taking a fee for it are also impermissible. When Allah prohibits something, He also prohibits its price. Furthermore, prohibited benefits cannot be compensated.