What is the ruling on investing in a trading company to which money is transferred to open a portfolio, and which provides guidance on buying and selling and expectations of stock price increases and decreases, and takes a 3% share of the profits, with the option of authorizing it to buy and sell or doing so personally?

Trading in pure shares is permissible under two conditions: the permissibility of the company's field of work, and that it does not invest in usurious banks. There is no objection to paying money to a brokerage firm to invest in this field in exchange for a percentage of the profit, without guaranteeing the capital, or for its role to be executing orders or signaling buying and selling in exchange for a commission. It must be noted that dealing with what is called "financial leverage" is not permissible because it is a loan that brings benefit to the company.