What is the ruling on trading currencies and metals through a financial broker using the margin system, where the broker covers part of the transaction value in exchange for a commission, noting that I bear all losses, do not receive interest, and do not own the full value of the transaction? And is it permissible to trade if I own the full amount or pay part of it?

It is not permissible to enter into a transaction by borrowing from a financial intermediary who earns a benefit (commission) for the lender. It is permissible if the intermediary's role is limited to providing market access and financial analysis for a specified commission, provided the full transaction value is paid and exchange conditions are observed. It is not permissible to take interest from a bank for depositing money or to pay money to a bank as interest on a loan. However, it is permissible to pay money for its safekeeping if it is a fee for a permissible service, keeping in mind that it is not permissible to deposit money in an interest-based bank except out of necessity.