What is the Islamic legal ruling on documentary credits in major international trade transactions, and what is the ruling on dealing with them through a usurious bank if the seller stipulates that to the buyer?

Summary of the Fatwa:

The ruling on Documentary Credits was previously detailed in Fatwa no. 67801. If the documentary credit is of the permissible type, there is no objection to a usurious bank acting as an agent, if an Islamic bank is not available and there is a need to deal with the usurious bank.