What is the ruling of Islamic law regarding the increase added by an Islamic bank to a deposit, which it claims is a "gift" resulting from Mudarabah (profit-sharing)? And is it permissible for Muslim students to accept this increase and spend it on charitable causes if it is prohibited?

There are two forms of bank deposits: 1. Current account: This is a loan from the client to the bank, which does not generate profits or interest, and no gifts are permissible on it. 2. Savings account / Investment deposit: This generates profits. In Islamic banks, it must be based on a valid Mudarabah (profit-sharing) contract, which requires: Investing the money in permissible activities. No guarantee of the capital unless the bank is negligent. Defining the profit as a common percentage of the actual profits, not of the capital.

What was mentioned – that the bank does not pay interest on the deposit, but rather invests the money and generates gifts – contradicts the nature of Mudarabah, which yields regular profits. It is necessary to review the Mudarabah contract or consult trustworthy scholars. If the Mudarabah is valid, there is no harm in taking the profits. If it is invalid, or if there is doubt about the bank's conduct, the profits must be disposed of by giving them to the poor, the needy, and for the general welfare of Muslims. In this case, depositing money in a current account is permissible out of necessity to preserve the funds.