Musannaf Ibn Abi Shayba 13:1127

Abu Bakr narrated to us, he said: Ibn Abi Za’idah narrated to us, from his father, from ‘Amir, regarding a slave between three [owners], and two of them emancipated him, then the slave died and he had wealth. He said: The two who emancipated him must pay the one who did not emancipate him one-third of his price. Then his inheritance is divided into three shares, for each man one share.