What is the ruling on fixing capital in trade with unstable profits, such as giving money to be invested and having it returned in full upon request?

In a Mudarabah contract, the profit-sharing ratio must be specified for both partners, and any losses are borne by the capital provider, with the worker (Mudarib) not incurring any part of them. It is not permissible to stipulate that the worker guarantees the capital or bears the loss; such a condition is invalid. The contract itself remains valid according to the majority of jurists, though some opine that the contract becomes void due to such a condition. The worker is considered a trustee of the funds and is not liable for their damage unless due to negligence or misconduct.