Tax Audit Support in Thailand

Received a tax notice? Start with the document and the deadline

Keep the complete notice, attachments, envelope and evidence of when it was received. Identify the taxpayer, issuing office, document reference, tax type, periods covered and requested action. A request to explain transactions, a formal summons and an assessment notice are different stages; they should not be treated as interchangeable.

1. Record the actual receipt date and the deadline stated in the notice. Ask an appropriately qualified adviser to verify the applicable rule, service method and any holiday adjustment.
2. Verify the office and officer through an independently obtained official contact. Do not use an unexpected payment link or disclose system passwords to an unverified caller.
3. Preserve the records immediately, including emails, accounting exports and previous submissions. Give one person responsibility for the correspondence log.
4. Collect what is available and list what is missing. If more time is needed, arrange a properly supported request through the correct channel; a request alone does not change the deadline.
5. Seek prompt review if an assessment, appeal deadline, enforcement step or allegation of deliberate wrongdoing is involved.

For an initial discussion, tell us the notice type, receipt date, stated deadline, tax periods and whether another accountant or lawyer is already involved. Agree a suitable document-transfer method before sending full tax files. Contact Pimaccounting about a tax notice. Sending an enquiry does not establish an engagement, file a response or extend any official deadline.

What tax audit support includes

Our accounting work can include a notice review, document inventory, ledger-to-return reconciliations, an issue register, supporting schedules, factual explanations, response-pack preparation and follow-up tracking. Where agreed and properly authorised, the engagement can include coordination with the Revenue Department and the taxpayer’s existing advisers.

A tax investigation is different from a statutory financial statement audit. Financial audit work addresses the financial statements under the applicable professional framework. Revenue Department enquiries concern tax obligations and supporting evidence. Audited accounts may be useful evidence, but do not establish that every tax treatment has been accepted.

We agree who prepares, reviews, signs, submits, attends meetings and approves payments. An accountant’s engagement is not automatically a mandate to represent a taxpayer in every procedure. Legal opinions, contested legal strategy, court representation and criminal defence require separately scoped assistance from appropriately qualified professionals.

Different types of enquiry, review and assessment

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The powers and procedures depend on the tax and statutory provision. See the Revenue Department’s assessment provisions and VAT inspection and assessment provisions. A useful first deliverable is a one-page case map showing the current stage, open questions, responsible people and next required action.

Tax situations we can help you prepare for

Corporate income tax: revenue, expenses and tax adjustments

Questions may involve differences between sales, bank receipts and reported revenue; cut-off between financial years; the business purpose and evidence for expenses; depreciation; inventory; bad debts; losses; or shareholder and director balances. We can reconcile the trial balance to financial statements and tax computations, trace significant transactions and prepare schedules explaining each adjustment.

A payment on a bank statement does not by itself prove a deductible business expense. We look for the contract, invoice, evidence of delivery, recipient, approval and connection to the business. Unresolved legal treatment is flagged for technical review. See corporate income tax support and the Revenue Department corporate tax guide.

VAT registration, output tax, input tax and refunds

VAT work can involve a registration history review, sales omitted from reports, mismatches between invoices and PP 30 returns, input-tax evidence, credit notes, branch particulars, refund claims or a claimed zero rate. We can organise invoice registers, reconcile purchase and sales reports and trace the actual movement of goods, services and money.

For exports and cross-border services, we collect contracts, delivery or customs records and evidence of where and how the service is used for the specialist’s review. A foreign customer or foreign-currency payment alone is not a complete analysis. Imported services and possible PP 36 obligations are reviewed separately. Refer to VAT registration and returns, official VAT guidance and tax invoice provisions.

Withholding tax and supplier payments

Typical questions concern the nature of a payment, who received it, withholding calculations, certificate details, return periods, payment evidence and differences between supplier ledgers and filed forms. We build a payment-by-payment schedule linking the contract, expense, recipient status, certificate and filing receipt. Overseas payments may require treaty and legal analysis before a position can be confirmed.

Where a certificate is missing or a supplier disputes a deduction, we distinguish the accounting evidence from the action needed to correct the underlying record. Read about withholding tax support and the Revenue Department’s withholding tax framework.

Payroll, employee benefits and contractor arrangements

We can compare payroll registers, employment documents, benefit policies, payment records, employee tax calculations and withholding submissions. Questions about directors’ remuneration, reimbursements, bonuses, accommodation or payments labelled as contractor fees require the actual arrangement to be understood, not just the ledger description.

Social security, employment law, immigration and work-permit issues follow their own rules. We can identify records that overlap and coordinate the accounting work, while the relevant specialist reviews the separate obligation. Explore payroll and work permit guidance.

Personal income tax and foreign-source income

For individual cases, the evidence may include residence-day records, employment and service contracts, income dates, remittances, foreign tax documents and the distinction between income and capital. We can organise a year-by-year factual schedule for review rather than treating every incoming transfer as the same type of receipt.

Foreign-source income questions require particular care over the applicable year, residence, income character, remittance facts and treaty position. See personal income tax services, the official foreign-source income questions and answers and foreign tax credit guidance. We do not infer an exemption simply because tax was paid overseas.

Complex business situations and special cases

Cash businesses, restaurants and marketplace sellers

Cash receipts, delivery platforms, card settlements, refunds, commissions and merchant deductions can produce very different totals. We reconcile gross sales to net settlements, bankings, refunds and fees without assuming that every difference is undeclared revenue. Inventory, wastage records, promotions and daily closing reports may help explain the operating picture. Sector guidance is available for restaurants and cafés and ecommerce businesses.

Foreign-owned companies and related-party transactions

Management fees, royalties, loans, interest, cost sharing and intercompany balances need an understandable commercial trail. We can assemble agreements, invoices, delivery evidence, calculations, counterparty details and reconciliations. Transfer pricing, treaty eligibility, beneficial ownership and permanent establishment questions are referred for the appropriate technical assessment. Accounting documentation alone is not a transfer-pricing study or legal opinion.

For a new structure, connect the review with company setup planning. For an established company, see accounting for foreign-owned businesses. Keep the entity being reviewed distinct from its owners and overseas affiliates.

BOI-promoted activities and incentive claims

We can organise the promotion certificate, conditions, project records, activity-level revenue and costs, asset schedules and prior benefit applications. The key is to connect a claim to the particular promoted activity and its conditions, rather than assume every company transaction receives the same treatment. Read BOI accounting support and the BOI’s corporate income tax benefit guidance.

Late returns, missing periods or a change of accountant

Start with a filing-and-payment status register. A draft return, an accepted filing and a paid liability are different records. We can compare the ledgers, submitted returns and receipts; identify missing periods; reconstruct supported balances; and prepare a correction plan for review. Avoid filing duplicate returns merely because an earlier submission cannot immediately be found.

A handover should identify who holds the source records, which periods are complete and which issues remain unresolved. Use catch-up bookkeeping and accountant handover support to address the underlying record gaps alongside the enquiry.

Inactive companies, restructuring, closure and liquidation

No current trading activity does not prove that every historical obligation is settled. We can review open tax periods, asset disposals, shareholder balances, outstanding returns and records held by former staff or providers. Coordinate the notice with the company’s authorised signatory or liquidator and any legal adviser. See company closure and liquidation.

Lost records, system migration or damaged documents

Preserve backups and original exports, record the cause and date of the loss and request legitimate replacement evidence from the issuer or custodian. We can prepare a reconstruction schedule showing the source, reliability and unresolved gaps for each entry. Reconstructed workings must be identified as such; they are not a licence to invent invoices, backdate agreements or alter original evidence. Any separate reporting duty for lost records needs prompt review.

Stamp duty, specific business tax and other authorities

Contracts, financing and property transactions can raise tax questions beyond routine CIT and VAT returns. We can organise agreements, dates, consideration and payment evidence for the correct specialist. Customs, excise, municipal taxes and Social Security Office enquiries have separate procedures. A Revenue Department appeal timetable must not be copied into those matters without checking the actual regime.

Suspected false invoices, deliberate evasion or criminal allegations

Escalate promptly to qualified Thai legal counsel. Preserve the records and coordinate a lawful response; do not delete communications, replace originals, coach a false account or obstruct officials. Our role can be to organise accounting evidence under an agreed scope. Criminal defence and court advocacy are not part of routine bookkeeping or this standard accounting support service.

Documents to prepare: a practical evidence checklist

Collect documents for the actual taxpayer, periods and issues requested. Keep an index and provide records through the agreed process; a large unlabelled file dump makes review harder. Maintain an unaltered source set and a separate working copy.

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Document translations should preserve the meaning and reference the original. Check whether the procedure requires a particular certification. Agree access permissions and retention arrangements with everyone involved; avoid circulating unnecessary employee identity or bank data.

How we organise the engagement

1. Intake and scope. Identify the stage, urgency, tax periods, existing advisers and conflicts or practical limits. Confirm the work we can accept and who owns each deadline.
2. Notice and records review. Create the correspondence log, document index and gap list. Confirm the submission channel and required authority with the responsible adviser.
3. Reconciliation and issue analysis. Connect the ledger, returns and external evidence. Separate confirmed facts, missing facts, arithmetic differences and questions requiring legal interpretation.
4. Response preparation. Draft a clear answer to each request, with numbered schedules and evidence references. Obtain management confirmation of factual statements and appropriate technical review.
5. Submission and meeting coordination. Work within the agreed mandate. Retain the final approved pack, proof of delivery or filing, meeting notes and any further requests.
6. Resolution and continuing actions. Record decisions, remaining issues, corrections, payments and any appeal workstream. Assign owners for process improvements and future filings.

For example, if bank receipts exceed reported sales, the working schedule should identify internal transfers, owner funding, customer deposits, timing differences and genuine sales items. Each explanation needs its own evidence. The objective is a supportable reconciliation, not a balancing entry that hides the difference.

The engagement may be limited to preparing records for your existing accountant or lawyer, or include broader accounting coordination. A clearly scoped assignment prevents two advisers filing inconsistent responses or assuming the other person is tracking a deadline.

Preparing for meetings and business-premises visits

Before a planned meeting, agree the attendees, agenda, document list and responsibility for answering questions. Make sure the people attending understand the transactions they will explain. Prepare a short business overview and a reconciliation pack, with access to the underlying evidence.

For VAT inspections, the Revenue Code provides specific inspection powers and requirements. Establish officials’ identity and authority and cooperate with lawful requests. Record the documents inspected, copied or taken, and obtain the appropriate inventory or receipt. Do not use an internal approval process to obstruct a lawful inspection.

During discussions, distinguish a confirmed fact from a point that needs checking. Keep accurate notes, correct errors promptly and obtain copies of records or statements you sign. If you do not understand a statement or its consequences, seek clarification and appropriate advice before signing. Afterward, circulate an action list with the next request, owner and deadline.

Deadlines, lookback periods and record retention are different

There is no single “tax audit period” that safely answers every case. A summons-issuance period, an assessment limit, a refund deadline, record-retention duties and the time to appeal are different legal questions. Filing history and the applicable tax matter.

Section 19 provides an ordinary two-year period for issuing a summons in the circumstances it describes, with an authorised extension up to five years in specified cases. This is not a universal rule that every audit must finish within two years. Non-filing is addressed separately under Section 23; VAT assessment periods have their own provisions, including Section 88/6.

We can build a chronology for the adviser to review: original due dates, actual filings, amendments, refund claims, notices, receipt dates and approved extensions. Keep records needed for an open enquiry, dispute or proceeding even when a routine retention date appears to have passed. Obtain case-specific advice before disposing of evidence.

Tax assessments, objections and appeals

On receiving an assessment, check the taxpayer, tax type, periods, legal basis, calculation and evidence of service. List the points accepted, disputed and requiring further information. A discussion with an officer is not a substitute for a valid appeal where a formal filing is needed.

For the usual assessment route governed by Section 30, the appeal period is 30 days from receipt of the assessment, subject to the applicable conditions and restrictions. Section 30 also provides a 30-day court-appeal period following receipt of the appeal decision, subject to Section 33. Different routes exist, so these numbers must not be applied to every notice or authority.

The Revenue Department’s appeal guidance explains the prescribed P.S.6 (ภ.ส.6) form, identification of each disputed assessment, grounds and supporting evidence. It also explains counting from the following day and the treatment of an official holiday on the final day. Verify the deadline against the actual service facts and current procedure. Late-appeal extension requests require reasons and approval; filing a request does not guarantee acceptance.

We can prepare the accounting chronology, reconcile disputed amounts, index evidence and support the adviser drafting the grounds. Confirm who is authorised to sign and submit, the correct office or channel, and what constitutes filing acceptance. Where electronic channels are used, review the current official submission conditions; an ordinary email or contact-form message is not automatically a valid appeal.

Unjustified failure to comply with certain summons or evidence requirements can affect appeal rights under the relevant provisions, including Sections 21, 25 and 33. If records are unavailable or attendance is impossible, obtain prompt advice on a lawful, documented response instead of ignoring the request.

Tax, penalties, surcharge and payment arrangements

An appeal does not automatically suspend payment. Under Section 31, payment deferral is a separate matter requiring the applicable permission. We can help assemble the accounting and cash-flow evidence for an adviser to review a deferral, security or instalment request. Do not assume collection is suspended while the request is pending.

An exposure schedule should separate principal tax, statutory penalties, surcharge, amounts already paid or credited and professional costs. Check each component by tax, period, legal basis and relevant dates. For example, Section 27 generally provides a surcharge of 1.5% per month or fraction under its conditions, capped at the tax payable. Different provisions or authorised exceptions may apply; this is not a universal calculator for every liability.

Penalty relief depends on the legal basis, procedural stage, facts and competent authority. The 2026 Revenue Department Order T.P.369/2569 amends specified reduction rules, including requirements concerning intention and cooperation; Order T.P.370/2569 addresses delegated authority and particular cases. Earlier applications may be subject to transitional rules. A current review is necessary before relying on an old penalty table.

We can organise the chronology, correction evidence, cooperation record and supporting calculations for a properly grounded request. A penalty reduction, surcharge treatment and tax reduction are distinct matters. We do not promise a waiver, negotiated outcome, refund or successful appeal.

Correcting errors and responding to refund reviews

If an error is found, first establish the correct facts, affected periods and consequences across related taxes. Correcting revenue may affect CIT, VAT, withholding or financial statements differently. Prepare the proposed correction, explanation and calculations for approval before filing through the appropriate process.

Keep the original return, amended version, change schedule and filing and payment evidence. Review the effect on an ongoing enquiry or appeal with the responsible adviser. A voluntary correction is not an automatic amnesty, and does not remove every penalty or procedural requirement.

For a refund review, match the claim to the underlying transaction, tax payment or certificate and any prior credits. Track what has been requested and supplied. We can improve the completeness and clarity of the file; the authority decides entitlement and processing. An unanswered request, elapsed time or a verbal conversation should not be recorded as written approval.

Deliverables, responsibilities and fees

A tailored quotation can cover a focused notice review, a defined reconciliation exercise, preparation of a response pack or continuing accounting support through several rounds of requests. The scope should specify the tax types and periods, expected records, deliverables, review stages and exclusions.

• Case and deadline register: notices, actual receipt dates, verified deadlines, owners and outstanding actions.
• Evidence index: source references, missing items and responsibility for obtaining replacements.
• Reconciliation pack: ledgers, returns, statements and transaction schedules with explained differences.
• Issue and response file: factual questions, specialist points, draft responses and approval history.
• Submission and meeting record: the final authorised version, delivery evidence, notes and follow-up requests.
• Close-out and improvement plan: remaining obligations, payment evidence, open disputes and recurring control changes.

Fees depend on the number of periods and entities, transaction volume, quality of the records, missing evidence, language work, complexity, urgency, meetings and coordination required. Tax, penalties, government charges, translation and external legal fees should be identified separately. See accounting service scope and quotation factors.

The taxpayer remains responsible for truthful and complete facts, management approvals and statutory obligations. Pimaccounting is responsible for the work accepted in the engagement. Any external lawyer or specialist has a separate defined role. Agree changes to scope if new tax periods, allegations or proceedings arise.

After the review: reduce recurring record problems

Convert findings into a short control plan: reconcile sales and bank settlements each month, review invoice quality, maintain withholding certificates, document related-party charges and close outstanding balance-sheet items. Assign a reviewer and retain evidence that the check happened.

Connect improvements with monthly bookkeeping, tax return preparation, accounting systems and compliance planning. A better process does not eliminate the possibility of a future enquiry; it makes the records easier to understand and explain.

Tax audit response tracker

Use our tax audit response tracker to organise notices, evidence requests, responsibilities, submissions, payment issues and appeal steps. You can fill it in locally and print or save a PDF. Entries are not sent to Pimaccounting and are not automatically saved.

This working sheet is not an official response or appeal form, does not calculate legal deadlines and does not submit anything to an authority. Have the responsible adviser verify each deadline and record the source. Explore the other accounting templates for supporting records.