The Prophet ﷺ forbade intercepting goods before they reached the markets, and he forbade najsh, and he said, "None of you may sell over the sale of another."
حدثنا عبد الرحمن عن مالك عن نافع
أن النبي ﷺ نهى عن تلقي السلع حتى يهبط بها الأسواق ونهى عن النجش وقال لا يبيع بعضكم على بيع بعض
Its isnad is sahih. It consists of three hadiths combined together. It has already appeared with this same isnad at 4531, with the addition of combining Maghrib and Isha during travel. It will come again on its own right after this, and see also 5010 and 5398.