Is zakat due on the original capital and profits only, or on the amount added to the original capital, knowing that the buying and selling with the added amount took place within four months?

Zakat is obligatory on capital and profits if a full year (hawl) has passed over them and they reach the nisab (minimum threshold) by themselves or when combined with other funds or trade goods. Profits are subordinate to the capital and are zakatable along with it, even if a full hawl has not passed over the profits themselves. Similarly, funds added to the capital become zakatable with their profits once a hawl has passed from the day of their acquisition, even if they do not reach the nisab on their own, because they are subordinate to the original capital. However, if the wealth is consumed before the end of the hawl, no zakat is due on it.