Musannaf Ibn Abi Shayba 13:2330

Abu Bakr narrated to us, he said: Isa ibn Yunus narrated to us, from al-Awza’i, from al-A’mash, from Ibrahim, that he said regarding the *mudarib* (the entrepreneur in a profit-sharing partnership): The profit is according to what they have agreed upon, and the loss is upon the capital. If they have divided the profit, then the loss is upon the capital. And if they have not divided it, the profit is returned to the capital.