Is Zakah due on profit from a Mudarabah (profit-sharing) partnership for the capital provider?
Chapter on Zakat on Trade Merchandise
Al-Mughni
Book of Zakat
Primary text
Zakah is obligatory upon the capital provider (Rab al-Mal) on the accumulated profit after a full Hawl has passed, because the profit in trade follows the ruling (Hawl) of its principal capital. The Zakah must be paid from the profit itself, as it is part of the running expenses of the capital, and it serves as protection (Wiqayah) for the principal. The evidence that the profit belongs to the capital provider is seen in that if the capital is lost after the profit has accrued, the loss falls upon the capital provider, and the worker's share is not considered fully his until division (Qismah) occurs.
Supporting text
A view from Al-Shafi'I states that Zakah is due on the entire amount (principal and profit) because the principal belongs to him, and the profit is an increment of his wealth. Another view suggests the worker (Mudarib) owes no Zakah on his share until division occurs, and only then does a new Hawl begin for him from that point. Another opinion suggests the worker owes Zakah on his share from the moment the profit reaches the threshold (Nisab) and is known, even before division, similar to a debt owed to the owner.