What is the ruling on opening an investment portfolio in Islamic Forex, where the company undertakes the trading itself in exchange for a percentage of the profits, with no commission on trading or overnight fees?

If the contract between the inquirer and the company is a mudarabah (profit-sharing) contract, and the company will operate with the inquirer’s funds without any loan from the company, and the company’s benefit will be a pre-agreed percentage of the profit, and the company adheres to Islamic regulations in trading currencies online, then there is no harm in that.