He attributed it to the Prophet ﷺ, who said, "When a slave is jointly owned by two people and one of them frees his share, if he is financially able, the slave is valued at a fair price, neither lower nor higher than its true worth, and then the slave is set free."
حدثنا سفيان
يبلغ به النبي ﷺ إذا كان العبد بين اثنين فأعتق أحدهما نصيبه فإن كان موسرا قوم عليه قيمة لا وكس ولا شطط ثم يعتق
Its isnad is sahih. Its meaning has already appeared in similar form at 4451. This wording is close to the wording of Bukhari 5:107-108, where he narrated it from Ibn Madini, from Sufyan, with this same isnad.Al-waks means deficiency. Al-shatat means injustice, wrongdoing, and deviation from the truth.