Answer
(Fatwa: 751/565/L=1431)
It is halal to buy the shares of any lawful company. However, until the purchased thing is not taken in possession it is not lawful to sell it to others. Also for possession, physical possession is not necessary; rather the legal possession is enough. Physical possession obviously means that that thing comes in the possession of buyer, while in legal possession the risk is transferred to buyer i.e. if any damage happens to the purchased thing, the buyer himself shall be liable for it. Within one day, generally one does not take the share in his possession; hence selling it is not lawful before taking it in possession. The hawkers take onions or other things in their possession and then sell it; there is no harm in it according to Islam. After buying shares generally one does not get it in his possession; hence its trade before possession is unlawful. The act of hawker cannot be judged with this parameter.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband