Yahya related to me from Malik that Yahya ibn Said bought some
property on behalf of his brother's sons who were orphans in his
house, and that that property was sold afterwards for a great deal of
profit.
Malik said, "There is no harm in using the property of orphans to trade with on their behalf if the one in charge of them has permission. Furthermore, I do not think that he is under any liability."
Malik said, "There is no harm in using the property of orphans to trade with on their behalf if the one in charge of them has permission. Furthermore, I do not think that he is under any liability."
Muwatta Malik Book 17, Hadith 17