What is the Shar'i ruling on the relationship between me and my employer, taking into account his purchase of shares in well-known companies using my card and his profit therefrom, then giving me a portion of this profit after deducting the larger part for himself, knowing that I am indebted to him, and I have spent the amount he gave me?

Trading in shares is permissible under two conditions: that the company's business is permissible, and that it does not deposit any of its capital in usurious banks. As for registering or subscribing to companies in someone else's name, if it is for a fee, it is permissible. If it is without a fee, it is permissible if the company's regulations and bylaws allow it.