What is the ruling on one who lends money to a person for him to invest it or to utilize its profits?

It is impermissible to take a stipulated increase from the borrower; this is usury (riba), forbidden by the Qur'an, Sunnah, and scholarly consensus. It is permissible to give money to be invested on the condition that the profit and loss are shared proportionally between the two parties. This is a legitimate Mudarabah (profit-sharing partnership).