Salim (may Allah have mercy on him) narrates from his father (Sayyiduna Abdullah bin Umar (may Allah be pleased with them both)) that he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever buys a slave, the (slave's) wealth belongs to the one who sold him, unless the buyer stipulates (otherwise)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7349