Hadith 505940
Chapter 17: Zakat - كتاب الزكاة
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم كَانَتْ تُعْطِي أَمْوَالَ الْيَتَامَى الَّذِينَ فِي حَجْرِهَا مَنْ يَتَّجِرُ لَهُمْ فِيهَا .
Yahya related to me from Malik that he had heard that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, used to give the property of the orphans that were in her house to whoever would use it to trade with on their behalf.
Reference Muwatta Malik 505940
USC-MSA web (English) reference : Book 17, Hadith 14