Praise be to Allaah.
Yes, he has to pay zakaah on this land, even if he has not
received the title deed, so long as the sale has been done and become
binding. So he has to pay the zakaah on trade goods, working out its value
at the market rate at the time when zakaah becomes due, and paying one
quarter of one tenth of its value. End quote.
Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen (18/234).