Musannaf Ibn Abi Shayba 13:1319

Abu Bakr narrated to us, he said: Hushaym narrated to us, from Mughira, from Ibrahim, who said: If the slave who has been granted permission to trade goes bankrupt, his debt is upon his own neck. If his master wishes to sell him, he may sell him and distribute his price among the creditors. And there is nothing upon him [the master] more than his [the slave's] price.