Musannaf Ibn Abi Shayba 13:924

Abu Bakr narrated to us, he said: Abd al-Samad ibn Abd al-Warith narrated to us, from Jarir ibn Hazim, who said: Hammad was asked about a slave who bought [something] without the permission of his master, then he [the master] emancipated him. He said: There is nothing upon him [the master], and their wealth is in the neck of the slave when he is emancipated.