All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is not permissible to deposit money in banks that deal with Riba (interest and/or usury) and it is not permissible to take the interest on the money deposited in them as we clarified in Fatwa 84188. As for depositing money in the Islamic banks, refer to Fataawa 85508 and 86125.
However, if someone has money and he does not know how to do business with it, or that he has no time to spend on business, then he may ask a businessman who is trustworthy and religious if there is a way to make a Mudhaarabah with him, and the like.
For more benefit about Mudhaarabah, please refer to Fataawa 87688 and 94668.