Is Zakat obligatory on the principal amount of the loan, which is 170,000 Riyals, or on the total amount due for repayment, which is 200,000 Riyals, if the purpose of the loan is investment?

The Zakat on money and trade goods must be paid if their total reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over them, taking into account what the person actually owns and what wealth is gained during the year. As for debts, the majority of scholars permit deducting them from the zakatable wealth, but it is more cautious not to deduct them. Regarding loans from Islamic banks, the increase due to deferment is considered a debt that can be deducted from zakatable wealth if we uphold the view of deducting debts. However, if the increase is interest-based (ribawi), it has a different ruling.