Is it permissible to trade currencies via Forex by depositing the full amount in a bank account and purchasing currencies equivalent to the capital to avoid leverage, with buying and selling restricted to currencies against the dollar, and is the condition of immediate possession considered fulfilled if the account balance becomes zero immediately after placing a buy order?

A banking entry for currency transfer is considered a constructive possession. The Islamic Fiqh Academy has permitted a delay in the banking entry for the customary period, but the beneficiary is not allowed to dispose of the currency until the effect of the banking entry materializes through the possibility of actual receipt. The transaction mentioned is free from Shariah prohibitions. However, depositing money in a usurious bank is not permissible except in cases of extreme necessity, provided it is deposited in a current account and the interest is disposed of by giving it to the poor.