How is wealth purified by zakat if it is given to a man for the purpose of trade in exchange for a certain percentage of the profit every four months, knowing that the profit is spent immediately and a year does not pass over it?

The profit from Mudarabah (definition) (partnership financing) wealth is subject to Zakat (definition) upon the completion of one Hawl (lunar year) for its principal capital. Any portion of the profit that also completes a Hawl alongside the principal is subject to Zakat. However, there is no Zakat on what was consumed from it before the completion of the Hawl. The profit must be a percentage of the actual profit, not a fixed amount.