Is it permissible to participate in a stock trading company by paying $1500 per share and receiving monthly payments of $400 for one year, knowing that the profit is not fixed but without loss?

For trading in shares, it is required that the company's activities be permissible and that it does not deposit its shareholders' money in usurious banks. As for the question, if the amount paid is a loan and includes a benefit for the lender, then it is haram (forbidden), based on the statement of Ibn al-Mundhir: "They unanimously agreed that if the lender stipulates a tenth of the loan as a gift or an increase, and he lends on that condition, then taking the increase is riba (usury)." If the amount is paid as a Mudarabah (partnership) with a guarantee of the capital, then the Mudarabah is invalid because the Mudarib (working partner) is entrusted, and the loss is borne by the capital provider, unless the Mudarib transgresses or defaults. The resolution of the Fiqh Academy states: "It is not permissible for the prospectus or Mudarabah certificates to contain a text guaranteeing the Mudarib's capital, or guaranteeing a fixed profit or a profit percentage of the capital. If such a stipulation occurs explicitly or implicitly, the guarantee condition is nullified, and the Mudarib is entitled to the profit of a Mudarabah of similar nature." Based on the foregoing, the transaction is haram.