Is it permissible to deal with Turkish banks that offer online gold trading, given the differing conditions for physical delivery of gold between them, where one bank stipulates reaching 5 kg for physical delivery, while the other only delivers the cash value?

As long as the first bank never enables the customer to take possession of the gold, and the second bank stipulates conditions that are not available to every customer and require prior notification, then the mutual possession (qabd) necessary for the validity of a gold sale is not met in either case. The Islamic Fiqh Academy has postponed making decisions on similar issues, such as owning gold through certificates representing specific quantities of it, due to the need for further conceptualization, technical, and jurisprudential research.