What is the ruling on investing money in a company that yields a daily profit of 3% for 90 days, with the capital not being withdrawable after this period?

It is impermissible in a partnership agreement to stipulate that the capital provider receives a percentage of the principal or a fixed amount. Rather, their share must be a percentage of the profit. If this is combined with a guarantee of the principal, the transaction becomes a usurious loan, as stated by Ibn Qudamah: "Whenever the share of one of the partners is made a known amount of money, or a known amount of money is added to their share... the partnership becomes void." And as stated by Shaykh al-Islam Ibn Taymiyyah: "If it is stipulated in a Mudarabah that the capital provider receives a specific amount of money, then this is impermissible by agreement." Furthermore, in a valid partnership, the investment field must be known and permissible. It is not permissible to invest money with ignorance regarding the method of its investment. The Prophet, peace be upon him, said: "Indeed, the Holy Spirit has inspired in my heart that no soul will die until it completes its term and fully receives its provision. So, fear Allah, and be excellent in seeking [provision]. And let not the slowness of provision lead any of you to seek it by disobeying Allah, for indeed, what is with Allah cannot be attained except through His obedience."