When does the Zakat year (Hawl) commence for newly acquired wealth?
Chapter on Zakat on Sheep
Al-Mughni
Book of Zakat
Primary text
If one gains wealth for which a Hawl is stipulated, and they have no other wealth, and it constitutes a Nisab, or if they have wealth of the same kind that did not reach the Nisab, but is completed by the newly acquired wealth, the Hawl for Zakat begins from the time of its acquisition. If one possesses a full Nisab, the newly acquired wealth falls into three categories. If it is growth from the original wealth (like trade profit or offspring of pasturing livestock), it joins the original wealth and its Hawl is followed. This is undisputed as it is a dependent part of the same kind.
Supporting text
If the acquired wealth is of a different kind than what is possessed, it is treated as a separate entity; it is not combined with the existing wealth for either the Nisab or the Hawl. If it constitutes a Nisab on its own, a new Hawl is started for it upon acquisition and Zakat is paid when the year completes. A third category is when wealth of the same kind as an existing Nisab is acquired, but that existing Nisab has already completed part of its Hawl; in this case, the newly acquired wealth must complete its own separate Hawl before Zakat becomes due on the combination. This is the position of Al-Shafi'i.