Received a request for explanation or additional information from the tax authority - how to prepare and respond

Since the Law on Tax Administration No. 108/2025/QH15 took effect on 1 July 2026, tax management has become increasingly data-driven: e-invoices, tax returns and bank data are cross-checked automatically. As a result, companies receive requests for explanation more often, even when they have done nothing wrong. The good news is that most of these requests can be closed at the explanation stage if you respond the right way.

Which type of notice have you received?

• A request for explanation during a desk review at the tax office. Under Clause 2, Article 22 of the 2025 Law on Tax Administration, the review is based on the tax dossier and data in the tax management information system; the tax authority may request explanations and additional information or documents, and may then issue a tax assessment, impose penalties or move to an inspection at the taxpayer's premises.
• A request to explain e-invoice risk. Under the e-invoice rules (Decree 123/2020/ND-CP as amended by Decree 70/2025/ND-CP, replaced by Decree 254/2026/ND-CP from 1 July 2026), when a business is rated very high risk, the tax authority sends an electronic notice and the business has a very short window (previously no more than 2 working days) to explain - check the exact deadline on the notice; if it cannot, the tax authority issues a notice suspending its use of e-invoices.
• A notice that part of a refund claim is risky and moved to pre-refund inspection, with requests for documents on specific transactions.
• Data mismatch queries between tax returns and e-invoice data, the financial statements, or different taxes.

A 6-step response process

1. Read carefully and diarise the deadline. Identify the legal basis, tax period, items queried and the response deadline stated in the notice. If you need more time, contact the tax officer early and send a written request giving reasons, rather than letting the deadline pass.
2. Rebuild the numbers. Reconcile the return with the accounting ledgers, e-invoice data, financial statements and bank statements to understand why the system flagged a difference. Many differences come from revenue timing, adjustment invoices or exchange rates.
3. Classify the outcome. If the figures are correct, prepare an explanation with evidence. If you find a genuine error, consider a supplementary return straight away: the 2025 Law on Tax Administration only allows supplementary returns within 5 years of the filing deadline of the period in error, and correcting voluntarily before the tax authority reaches a conclusion is usually the better position.
4. Draft the explanation. Answer each query in the order raised, giving for each: the figures, the cause, the legal basis and a list of supporting documents. Avoid generic explanations or volunteering information that was not asked for.
5. File through the right channel and keep proof. Submit electronically as instructed in the notice, with a valid digital signature, and keep the receipt and a full copy of what was sent. Under Article 6 of Circular 89/2026/TT-BTC, the tax authority may not ask for documents already in the tax dossier or obtainable from other databases, so you can refer to them instead of resubmitting.
6. Follow through until closure. If invited to a meeting, bring someone with authority and someone who knows the numbers, ask for minutes to be taken and read them carefully before signing.

Writing a persuasive explanation

A good explanation gives the tax officer enough basis to accept it without further questions. Use reconciliation tables rather than long paragraphs, number documents to match each query, and cite the applicable provisions precisely. Illustrative example: the tax authority asks why revenue on the VAT return is lower than total output invoices in the system. A persuasive reply lists downward adjustment invoices, replacement invoices and invoices issued for the next period, with a reconciliation that bridges exactly to the figure on the return.

Prevention: fewer queries in the first place

The tax authority groups taxpayers by compliance level and risk; compliant businesses are prioritised for automated processing and remote checks. Monthly reconciliation of returns, e-invoices and ledgers, checking supplier status before payment, and filing documents by transaction are three habits that significantly reduce the number of notices you need to handle.

How Kaizen can help

Kaizen reads the notice, rebuilds the numbers, drafts the explanation and represents you before the tax authority when needed, drawing on more than 17 years of Big4 experience. Book a free tax health check to review in advance the points in your filings most likely to be queried.