All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

The above question should take the following form: Is he compelled to give the Zakah of that amount or not? This is because the word permissible refers to an act for which one isn`t held sinful and this includes the compulsory (Wajib ), the desirable but not compulsory (Mustahab),  and the lawful (Mubah). These are different rulings.

If the debtor acknowledges the debt and can afford repaying it, then the creditor should pay its Zakah immediately in case one full lunar year has passed over possessing Nisaab (Minimum amount liable for Zakah), because it is tantamount to the wealth in his possession. However, if the debtor doesn`t acknowledge the debt or unable to repay it, then the creditor isn`t obliged to pay its Zakah until he receives it. Once he does, he should pay the Zakah due on it for all past years. In addition, Maliki scholars said: "He (Creditor) should pay its Zakah for one year only and this is a reliable opinion to follow. Fatwas of late Sheikh Nooh Bin Salman; Zakah Fatwas: Fatwa No. (31). And Allah the Almighty knows best.