What is the ruling on imposing financial penalties for late payment of the monthly sum, or for withdrawal from the group, or for joining it, in an agreement aimed at collecting money for investment in a commercial project?

Increasing the company's capital is permissible, and the stipulation of a fixed term for the company is a matter of scholarly disagreement. However, stipulating a financial penalty for late payment or withdrawal, or requiring a payment to join the company, presents a problem. Sheikh al-Islam Ibn Taymiyyah views this as impermissible because it is considered gharar (excessive uncertainty) and gambling, as it stipulates something for one of the partners that is outside his common share of the profit. He considers this akin to stipulating a specific profit or a fixed amount of money, which leads to injustice and corruption. And a gift presented because of a transaction is treated like money received through a contract, such as a gift from a worker to the capital owner in a mudarabah (profit-sharing) partnership. Thus, it is not permissible for the capital owner to take anything from it unless all of it is accounted for him.