How is a company's Zakat calculated in the presence of bad debts?

Non-performing loans within companies fall under the category of non-performing debts, and Zakat (definition) is due on them for one year if they are collected. These are debts that are impossible to collect for a valid reason, and they remain on the books until the creditor company confirms the impossibility of their collection, at which point it considers them a bad debt and closes their accounts. Zakat is not obligatory on them until they are collected.