Musannaf Ibn Abi Shayba 13:8

'Abd al-Samad ibn 'Abd al-Warith narrated to us, from Shu'bah, who said: I asked al-Hakam, Hammad, and Qatadah about two men who entered into a partnership. One of them brought two thousand, and the other brought one thousand, and they entered into a partnership and stipulated that the loss would be between them [equally], and the profit would be half and half. They said: The profit is according to what they stipulated, and the loss is according to the [proportion of the] capital.