What is the ruling on trading in international stock exchanges (London - New York - Hong Kong) by buying and selling currencies and metals through the margin system via a financial broker, taking into account that the trader pays a portion of the deal's value and the broker pays the remainder, and the trader bears the full loss and pays a commission to the broker only upon selling, and the broker does not take anything from the profits? And does this transaction become permissible শরীয়ত if the trader possesses the full amount, or if he pays the full value of the deal himself?

Global stock exchange transactions using the "margin" system are not free of شرعي (Sharia-compliant) prohibitions, including the lack of immediate exchange (taqabud), the inclusion of usury (riba) due to the broker benefiting from the loan provided to the client, and the forbidden combination of a loan and a sale. Additionally, there are usurious overnight fees (rusum al-tabyit). These practices render the contract void and forbidden.

However, if immediate exchange (taqabud) is realized, overnight fees are eliminated, and the broker's role is limited to providing market access and price information for a defined commission without offering a loan, then dealing becomes permissible. This applies whether the client pays the full price or borrows a portion from a third party unrelated to the broker.