Is buying and selling shares of international companies such as Mercedes and Apple permissible (halal) or forbidden (haram), when their full value is paid electronically through a broker in the stock market who takes a percentage or a fixed amount, and there is no way to know if these companies deal with bank loans?

It is a condition that the shares intended for investment be Islamically permissible. This means that the company's activity must be a permissible commercial one, whether in industry, agriculture, or selling goods. Furthermore, it must not deposit its funds or invest them in interest-based banks, nor borrow from them with interest. What is permissible is permissible wherever it may be, and what is unlawful is unlawful wherever it may be. There is no harm in the broker taking a percentage or a lump sum in exchange for selling the shares.