Shaykh Abdul-Muhsin al-Abbaad was asked the following question:
Nowadays, a man sells [a product] after having the receipt/invoice and the product is in the warehouse. Likewise, the product is sold and bought while it is still in the same warehouse.
“This is not allowed. It opposes these Ahaadith*. Verily selling occurs when the buyer purchases it [the product] then owns it. As for selling it before owning it, then that is not for him”.
[Sharh Sunan Ibn Majah no. 159]
*One of the Ahaadith the Shaikh is referring to is the following:
عَنْ حَكِيمِ بْنِ حِزَامٍ، قَالَ قُلْتُ يَا رَسُولَ اللَّهِ الرَّجُلُ يَسْأَلُنِي الْبَيْعَ وَلَيْسَ عِنْدِي أَفَأَبِيعُهُ قَالَ “ لاَ تَبِعْ مَا لَيْسَ عِنْدَكَ
It was narrated that Hakim bin Hizam said:
“I said: ‘O Messenger of Allah, a man is asking me to sell him something that I do not possess; Shall I sell it to him?’ He said: ‘Do not sell what is not with you.
[Saheeh Ibn Majah no. 1794]
Faisal Ibn Abdul Qaadir Ibn Hassan