Narrated by:Ibn 'Umar that
It was narrated from Ibn 'Umar that:the Prophet forbade artificially inflating prices.
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم نَهَى عَنِ النَّجْشِ .
Nesai
The Book of Financial Transactions • Hadith 4505