How is the zakat on money to be paid if the principal has reached the nisab and been invested in a business, but the time of receiving the profits and their value have not yet been determined?

If the money reaches the nisab (the minimum amount on which zakat is due), zakat becomes obligatory on it after the completion of a full Hijri year, provided it has not fallen below the nisab. If the money is invested in Mudarabah (profit-sharing partnership), the zakat on the profit becomes obligatory as soon as it appears, even before the completion of the year, following the principal capital. However, if the profit does not appear until after the year, then only the zakat on the principal capital is obligatory.

If profit appears but has not yet been received, its zakat is obligatory once its amount is known. If the amount cannot be known, then zakat is only obligatory on what is certainly known to have entered one's possession, and there is no zakat on what is doubtful. If it is later confirmed that there is additional profit, then its zakat becomes obligatory.