What is the ruling on Salam selling, and what is the difference between it and trading in global stock markets for gold, silver, currencies, and products in the long term?

Sale by Salam (forward sale) is permissible, and among its most important conditions, according to the majority of scholars, is the delivery of the capital at the contracting session. It must also not involve two monetary instruments, such as selling gold for silver, because that is Sarf (currency exchange), which requires hand-to-hand possession. Consequently, Salam is not permissible for gold and silver or for currencies exchanged among themselves. However, it is permissible for other commodities like petroleum and grains, while observing the other conditions of Salam.