In order to interpret tax accounts correctly, it is useful to be aware of some of the basic principles on the basis of which the NTCA keeps tax accounts and records individual items. These include, but are not limited to:
- one taxpayer one tax account: the NTCA keeps tax accounts for each taxpayer. Each taxpayer has only one tax account. The office records this on the tax identification number for sole traders and individuals and on the tax number for other taxpayers.
- settlement when payment is due: if less than the required amount has been paid for a tax, the payment is always accounted for in the order in which it is due, i.e. always for the earliest debt. There are, however, some exceptions where the payment can only be charged to a specific liability, mostly related to a customs procedure.
- annual closing: tax accounts are kept by the NTCA on an annual basis. They must provide a permanent, "final" status for which there is no retrospective accounting. With this in mind, tax accounts can also be queried on an annual basis. At the year-end closing, the liabilities and cash flows for the closed period are aggregated by tax type. This ideally results in an orderly, zero balance, but it can also reflect a debt or surplus. The balance appears as the "opening balance" for the current period, with a date of 1 January. This ensures that the aggregated balance of items from previous periods is always reflected in the current tax account balance.
- the assessment of the net late payment surcharge: late payments will be penalised by the NTCA with a late payment surcharge at the central bank base rate. The allowance is always calculated and prescribed in the year following the year in question.