Is it permissible to buy and sell platinum from a bank's application if the metal is not available to them and the buying and selling are for the purpose of profit?

It is permissible to purchase platinum with money without the condition of immediate possession (qabd) in the same session, but knowledge of the item sold (seeing it or having it described) is required. It is not permissible to sell platinum before taking possession of it, due to the Prophet's (peace be upon him) saying: "If you buy a commodity, do not sell it until you take possession of it." If the bank sells platinum on the condition that it will deliver it at a known time, with known specifications and weight, then this is a salam sale, which is permissible, but it is not permissible to sell it until possession is taken. However, if the bank undertakes to purchase platinum on your behalf and then sell it to someone who buys from you, this is forbidden and falls under organized tawarruq banking. If you are buying and selling platinum without it actually existing in the bank, this is an obvious stratagem for riba (usury), as it is money for money.