Is Zakat due on the profit from selling deferred shares, or on the principal and the profit together?

The view of the majority of scholars is that debt waives Zakat on hidden assets. If you have non-Zakat-eligible assets that exceed your needs, and their value is equivalent to the debt, then assign them against the debt and pay Zakat on any excess cash and trade goods that reach the nisab. However, if the debt covers all your possessions, or the remainder after the debt is less than the nisab, then no Zakat is due on you.

So, if the debt is 100,000 and it is not offset by non-Zakat-eligible assets, and you sold shares for 115,000: if the 15,000 reaches the nisab and the buyer is solvent, then the hawl (Zakat year) for the nisab begins from the time the profit reaching the nisab becomes apparent, and the 15,000 is subject to Zakat after a year has passed. If you have properties exceeding your needs that cover the value of the debt, then Zakat is due on the entire 115,000; otherwise, it is due on whatever remains for you from it.