Musannaf Ibn Abi Shayba 13:1517

Abu Bakr narrated to us, he said: Ghundar narrated to us, from Ash'ath, from al-Hasan, that he was asked about a man who gave money to a man as a *mudaraba* (profit-sharing) contract and stipulated upon him *bida'a* (that he trade with some of it for the owner's sole benefit). He disliked it. And Ibn Sirin did not see any harm in it.