Wa alaykum as salaam. There is ikhtelaaf on the matter of stock investments, but futures and options are generally impermissible unless you knew the one you're buying the futures commodity from and selling it to are not muslims, which as far as I know is not possible online ( do consult a mufti on this though to be sure)
Regarding stock investments, Mufti Nizamuddin says it's not permissible because companies take interest based loans( through bank loans and preference shares) to run their businesses and as a shareholder you would be liable for that. I asked him, how then is it permissible to take interest from banks that sell their shares in the stock exchange? (for that would mean a muslim could very well be a part owner of the bank and hence impermissible for muslims to take interest from such a company). He could not provide me with a satisfactory answer. I asked Mufti Akmal the same question, and he replied ( and even posted a video on youtube, apparently correcting his previous answer on the subject), that in such a scenario receiving interest from such a bank would be impermissible.
Tajus Shariah was of the view that buying shares was not permissible, except if they were preference shares issued by a non muslim company. He said investing in shares was akin to gambling, hence impermissible.
The Turkish sunnis, who own the hakikatkitabevi site, hold it permissible to buy and sell stocks, as long as the company is engaged in a halal business, regardless if they use usurious loans to run their business or not.
Jamia Nizamia of Hyderabad, gave a fatwa allowing stock investments in companies doing permissible business even if they use usurious loans, as long as such companies are owned by non muslims.
