How is zakat paid on money saved in one account, which is spent on building and furnishing properties and furnished apartments, and on buying and selling lands and stocks, knowing that the sources of income are multiple, such as renting properties, selling them, and salaries?

Zakat must be paid on money if it reaches the nisab (threshold) and a hawl (one lunar year) passes over it. Cash is added to trade goods to complete the nisab, and trade goods are valued at their market price at the time the hawl is completed. Then, one-quarter of one-tenth (2.5%) of the total cash and trade goods is paid. Money spent during the hawl is not subject to zakat. As for money gained during the hawl, if it is profit from trade, its hawl is the same as thel principal. If it is from other sources (such as rents and salaries), a new hawl begins for it. It is permissible to pay zakat on all money when the hawl of the principal is completed, for ease, and this is considered an advance payment of zakat on some of the money, which is permissible.