What is the ruling on depositing money in a bank with an investment certificate that has a monthly disbursed profit margin? Is that considered usury?

An investment certificate is a document that proves the right to an amount deposited with the bank, and its ruling varies depending on its type: - Investment certificates with variable returns in Islamic banks: These are permissible, and are considered a legitimate mudarabah (profit-sharing partnership) where the bank invests the money in permissible projects in exchange for a percentage of the profit, without guaranteeing the capital or a known profit. - Investment certificates with fixed, guaranteed returns: These are forbidden, and are considered a usurious loan; because they are a loan with an increase on the capital.

Whoever has engaged in the forbidden type must dispose of the interest by giving it to the poor and needy, and withdraw their money.