Is zakat obligatory upon the capital owner or upon the worker in a joint venture, and what is the difference in zakat between lending and partnership in a project?

It was previously explained that the most preponderant view regarding zakat on mudarabah (profit-sharing) is that of the Hanbalis. Accordingly, zakat must be paid on the principal capital and the mudarib's (agent's) share of the profit immediately after the hawl (one lunar year) has passed. However, zakat is not obligatory on the rabb al-mal (financier's) share of the profit until after the contract ends and the money is distributed, at which point a new hawl begins for it.

As for zakat on debts: If the debtor acknowledges the debt and is able to repay it, then zakat is obligatory on the creditor for it every year, provided it reaches the nisab (minimum threshold). If the debtor is in financial straits, or denies the debt, or delays payment, then zakat is not obligatory until the debt is collected, and it is paid for one year only, even if the debt remained for several years.