What is the religious ruling on bank interest and investment certificates?

It is not permissible to invest money in interest-based (riba-based) banks, and the returns they offer are forbidden because they constitute usury (riba). Similarly, investment certificates issued by interest-based banks are forbidden. However, Islamic banks that operate according to the rulings of Sharia and provide profits based on sound Mudarabah (profit-sharing) are permissible. Therefore, if you wish to invest your money in banks, you should choose Islamic banks whose transactions adhere to the controls of Sharia.