What is the ruling on online currency trading, and is that considered "qabdh" (seizure or possession) in the same session, and what is the ruling on stock trading if currency trading is prohibited?

The margin system (trading on margin) is usurious because it involves a loan with interest, and it carries significant risks. Currency trading is permissible only with immediate spot exchange, and it is not permissible to prioritize one over the other (mufadalah) because it falls under the usurious categories. Stock trading on international exchanges often involves Sharia-related prohibitions, such as non-actual forward contracts, selling what one does not own, repeated selling before taking possession, monopolization, and prices being affected by non-real factors. Furthermore, one must be cautious about stocks in forbidden institutions or those that deal with usury. If these prohibitions are avoided, then there is no harm in stock trading.