A deduction is not allowed for a debt owed to a trader except:
•a bad debt;
•a doubtful debt to the extent estimated to be bad. In the case of the bankruptcy or insolvency of the debtor, this means the debt except to the extent that any amount may reasonably be expected to be received on the debt;
•a debt or part of a debt released by the creditor wholly and exclusively for the purposes of the trade as part of a statutory insolvency arrangement.