Improper input tax credit (ITC) documentation is one of the main reasons for GST/HST reassessments. Proper invoices to support ITCs are required by Canada Revenue Agency auditors. For example, the input tax credit may be disallowed if only the credit card slip is provided rather than the actual invoice.

The supplier’s GST/HST registration number should be printed on the source document. Some clients use credit card receipts, bank statements, and cancelled cheques to substantiate the GST/HST input tax credits. However, none of these documents show the supplier’s GST/HST registration number.