All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The recipients of Zakat were determined by Allah the Almighty in his saying (which means): {Zakat expenditures are only for the poor and for the needy and for those employed for it and for bringing hearts together [for Islam] and for freeing captives [or slaves] and for those in debt and for the cause of Allah and for the [stranded] traveler - an obligation [imposed] by Allah. And Allah is Knowing and Wise.} [Quran 9:60]
It is not permissible to spend the money of Zakat to compensate lost money unless the one who lost it is obliged to compensate it and he is poor and does not own anything to compensate for that. So, in this case, he is entitled to be given zakat for being a debtor.
We point out that the basic ruling in the entrusted person, in case of a deposit, leasing, borrowing, agency and the like, which was taken with the permission of its owner, is that he does not guarantee it in case of damage unless he has transgressed or was negligent.
Allah knows best.