How is the zakat calculated for an amount of 20,0, of which 12,0 has been invested in variable-price shares of a transportation company, and 8,0 has remained in the bank? Is it permissible to speculate with shares by buying and selling?

Depositing money in usurious banks is prohibited except out of necessity. The interest generated from it is not permissible to own; rather, it must be disposed of by spending it on charitable causes. Zakat (definition) is obligatory on money deposited in the bank and on commercial stocks if they reach the nisab (definition) (minimum threshold) and a hawl (one lunar year) passes over them. Stocks are valued at the end of the hawl, added to the deposited money, and zakat is paid on the total amount. As for non-commercial stocks (fixed assets), there is no zakat on them; rather, zakat is due on their income if it reaches the nisab and a hawl passes over it.