What is the ruling on selling a bank certificate that has not yet matured, so that the buyer pays its value and benefits from its profits?

It is not permissible to assign an investment certificate to another person to take your place in receiving the profits, even if the certificate is permissible and considered a Mudarabah (partnership). The prohibition here is due to the presence of gharar (excessive uncertainty) and not knowing whether the capital was cash or goods (assets) with the bank at the time of the contract. Therefore, the sale is not valid without verifying whether it was entirely or mostly goods. The prohibition is even more paramount if the certificate is impermissible (a usurious loan). In fact, one must withdraw the deposit and refrain from this transaction.