Is zakat due on real estate that was purchased with the intention of generating income and then sold due to market changes, and how is zakat calculated in this case, on the capital and profit or on the profit only? Is it permissible to give it out without the owner's knowledge? What are the cases of zakat where it is paid only on the profit?

Selling real estate without the owner's permission is called "unauthorized selling" (بيع الفضولي). Scholars have differed regarding its validity. The juristic opinion we adopt is that its validity depends on the owner's ratification. If the owner ratifies it, the sale is valid; if he rejects it, it is null and void. There is no Zakat on real estate for its owner for two reasons: firstly, he did not purchase it with the intention of trade; and secondly, he never intended to sell it at all, but rather it was sold on his behalf without his permission. The value of the real estate is subject to Zakat if a hawl (lunar year) passes over it after the sale. It is not permissible to give out Zakat without the owner's knowledge, because it is an act of worship that requires intention. In principle, both the capital and the profit are subject to Zakat together. As for income-generating assets (such as real estate not intended for sale), Zakat is obligatory on their income if it reaches the nisab (minimum threshold) and a hawl passes over it. Zakat is not obligatory on the value of the income-generating assets themselves.