Is it permissible to pay Zakat on money after every business transaction, or must one wait for a full year to elapse?

Zakat on trade goods is obligatory under two conditions: the value of the goods reaching the nisab (minimum taxable amount) and the passing of a hawl (one lunar year). The hawl for trade goods is the hawl of the money with which they were purchased. What a merchant does by paying zakat annually before the hawl is due is an advanced payment, which is permissible if the nisab has been reached.

However, only the zakat on the nisab should be advanced, not on the profit. If one advances the zakat on both the nisab and the profit together, the zakat on the nisab is valid, but not on the profit. If zakat is advanced, the merchant is required, upon the arrival of the hawl, to calculate the obligatory zakat and then review what was advanced. If the advanced amount is not less than the obligatory amount, it suffices; otherwise, the remaining amount must be paid. As for advancing zakat when the trade goods have not reached the nisab, this is not sufficient, and it is impermissible to advance zakat before possessing the nisab.