Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation

Thai tax reference — 75 answers

Compiled from the Revenue Code (ss. 40, 41, 48, 65 bis/ter, 70, 71 bis), RD Orders Por. 161/2566 and 162/2566, the transfer-pricing notifications implementing OECD BEPS Action 13, Thailand's double tax agreement network and the LTR visa tax Royal Decrees, as cited on each service page. Filing deadlines and thresholds change — verify with the Revenue Department (rd.go.th) before relying on a tax position. For fees and a case assessment, contact our team by phone, LINE or email.

• Q18091. What is Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation?

  3-tier defence: (1) audit — RD negotiation, rebuttal, response letters (2) appeal to Tax Ruling Committee within 30 days (3) Central Tax Court first instance 6–12 months + appeal 6–9 months — retainer quoted on request + 8% success fee.

• Q18092. How long does Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation take?

  Typical turnaround 12–24 months to first-instance judgment. Durations are estimates that depend on document completeness, Revenue Department processing queues and, in disputes, the hearing calendar of the Appeal Commission or the Central Tax Court.

• Q18093. How much does Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation cost?

  Fees depend on the transaction structure, the number of entities and jurisdictions involved and the documentation workload; Revenue Department and Tax Court charges are official rates passed through at cost. Contact our team for a case-by-case assessment: +66 83-249-4999 · LINE @NYCLI · nyclegal@ilc.ltd

• Q18094. Who is Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation for?

  End-to-end tax audit defence: RD field/desk audit → assessment order → Tax Ruling Committee → Central Tax Court. Covers CIT, VAT, WH, TP, digital service, specific business.

• Q18095. How does the RD audit?

  (1) Desk audit — system-screened; (2) Field audit — on-site inspection; (3) Special audit — complex cases (TP, cross-border, restructures); (4) Investigation — suspected fraud.

• Q18096. How is a response letter drafted?

  (1) Cite legal basis (RC section) (2) attach supporting doc references (3) argue by tax ruling / precedent (4) defensible methodology (5) offer 3 settlement scenarios — file within 15 days.

• Q18097. RD assessment limitation period?

  Default 5 years (RC §19); no-return-filed = 10 years (§19 ¶2); wilful evasion = no limit. Beware acknowledging debt — it resets RD's clock.

• Q18098. Taxpayer win-rate at Tax Court?

  Central Tax Court 2021–2023: taxpayer full win 42%, partial 24%, loss 34% — higher than general civil courts because RD bears heavier evidentiary burden.

• Q18099. How is the 8% success fee computed?

  8% of the tax + penalty + surcharge actually reduced after final ruling. Capped at 20% of the sum in dispute (Lawyers Council rules). Full loss = retainer + pre-agreed hourly only.

• Q18100. Which sources back the Tax Audit Defense — Full Revenue Department Assessment + Appeal Representation page?

  Official sources cited: https://www.rd.go.th/english/ · https://www.rd.go.th/english/766.html

• Q18114. Thai tax legal basis #1 — what does it say?

  Revenue Code s. 41 para. 3 — an individual present in Thailand for 180 days or more in a tax year is a Thai tax resident for that year and is taxable on foreign-source income when it is brought into Thailand. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18115. Thai tax legal basis #2 — what does it say?

  RD Orders Por. 161/2566 and 162/2566 — foreign-source income arising from 1 January 2024 is taxable in the year it is remitted to Thailand, replacing the former same-year remittance practice. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18116. Thai tax legal basis #3 — what does it say?

  Revenue Code s. 40 — assessable income is classified into eight categories, each with its own deduction rules and withholding rates. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18117. Thai tax legal basis #4 — what does it say?

  Revenue Code s. 48 — progressive personal income tax of 0–35%, with the first quoted on request of net income exempt by Royal Decree. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18118. Thai tax legal basis #5 — what does it say?

  Revenue Code ss. 65 bis and 65 ter — the statutory basis for computing net corporate profit and for non-deductible expenses. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18119. Thai tax legal basis #6 — what does it say?

  Revenue Code s. 71 bis — assessment officers may adjust income and expenses between related parties to arm's-length terms (transfer pricing). Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18120. Thai tax legal basis #7 — what does it say?

  Director-General Notification No. 407 (2021) with Ministerial Regulation No. 369 — companies with revenue of quoted on request million or more per accounting period must file the related-party Disclosure Form and prepare a Local File. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18121. Thai tax legal basis #8 — what does it say?

  OECD BEPS Action 13 — the three-tier documentation model (Master File / Local File / Country-by-Country Report) adopted in Thai practice; CbCR applies to MNE groups meeting the published revenue threshold. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18122. Thai tax legal basis #9 — what does it say?

  Revenue Code s. 70 — withholding tax on payments abroad, which may be reduced under an applicable double tax agreement. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18123. Thai tax legal basis #10 — what does it say?

  Double tax agreements — treaty relief requires proof of tax residence (Certificate of Residence, R.O.01) and satisfaction of the beneficial-ownership test. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18124. Thai tax legal basis #11 — what does it say?

  VAT — registration (Por.Por.01) is mandatory above quoted on request.8 million of annual revenue, with monthly Por.Por.30 returns due by the 15th of the following month. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18125. Thai tax legal basis #12 — what does it say?

  Act on the Establishment of and Procedure for the Tax Court B.E. 2528 — assessment appeals go to the Appeal Commission before an action may be filed at the Central Tax Court within the statutory deadline. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q18126. Thai tax legal basis #13 — what does it say?

  LTR visa tax Royal Decrees — reduced-rate and exemption benefits for Highly-Skilled Professionals and the conditions attaching to foreign income; verify the current conditions at ltr.boi.go.th. Verify the text, notifications and current practice with the Revenue Department: https://www.rd.go.th/english/

• Q926162. What are the end-to-end steps for tax audit defense?

  We start with a document and fact review, prepare and verify the file, submit to the Revenue Department, follow up on any queries raised by officials, and hand over the completed result with a full copy set. For tax audit defense a case manager tracks every stage and reports status. Call +66 83-249-4999 · LINE @NYCLI · nyclegal@ilc.ltd

• Q926164. Which documents are required for tax audit defense?

  The baseline set is the applicant's ID or passport, the original documents relating to tax audit defense, proof of connection (house registration, company affidavit or the underlying contract) and a power of attorney if a representative attends. The exact list follows the Revenue Department requirements on the filing date; we send a case-specific checklist before your appointment.

• Q926166. How long does tax audit defense take?

  Timing depends on the Revenue Department queue, how complete your file is, and public holidays. Our own preparation usually takes a few business days; the official stage is an estimate that can shift. We give you a realistic tax audit defense timeline before starting and update you as it progresses.

• Q926168. What costs are involved in tax audit defense and how are they calculated?

  There are two components: official government fees passed through at the published rate, and our professional fee, which depends on scope, document volume and urgency of tax audit defense. Fees are quoted case by case based on complexity and document volume — ask our team before work starts. You always receive a written breakdown before work begins — no hidden charges.

• Q926170. Can tax audit defense be handled if I live upcountry or overseas?

  Yes. Send photos of your documents via LINE for a feasibility check, then we proceed under a power of attorney, or you sign at a Royal Thai Embassy/Consulate where you live and courier the originals back. For tax audit defense we map out the fastest and safest option before you commit.

• Q926172. What are the most common mistakes in tax audit defense and how do we prevent them?

  The usual causes of rejection are name spellings that differ between documents, documents that expire before the filing date, uncertified copies, and translations that do not match the original. the Revenue Department returns files for exactly these reasons, so we cross-check names, dates and seals across every page before submitting tax audit defense.

• Q926174. Which laws or regulations govern tax audit defense?

  The framework is set by the Revenue Code and Thailand's double tax agreements, together with the regulations and notifications issued by the Revenue Department, which are revised from time to time. Before advising on tax audit defense we verify the version in force on the filing date and rely on official sources rather than second-hand summaries.

• Q926176. What happens if tax audit defense is rejected or returned for correction?

  First we obtain the written reason from the Revenue Department, then separate formal defects (fixable and quickly refiled) from substantive or eligibility issues (which need a change of approach). Where the error is ours, we redo tax audit defense at no extra professional fee and coordinate until the matter is resolved.

• Q926178. Who is tax audit defense for, and what are the eligibility conditions?

  It suits anyone who must present the result of tax audit defense to a government body, bank, educational institution or overseas counterparty. Applicant eligibility and supporting documents follow the Revenue Department rules; some cases require the document holder in person or a properly executed power of attorney. We screen eligibility free of charge before accepting the case.

• Q926180. How long does the result of tax audit defense stay valid?

  Certified documents rarely carry an expiry date themselves, but most receiving authorities require issuance within 3–6 months of submission, and some are stricter. Check the destination's rule before starting tax audit defense so nothing has to be redone; we plan the sequence around your filing deadline.

• Q926182. Does tax audit defense also need an English or target-language translation?

  If the receiving body is overseas, a certified translation is normally required, and many countries insist on their own official language rather than English. We confirm the destination rule first, then produce a translation aligned with tax audit defense and certify it in the same workflow to avoid extra rounds.

• Q926184. Should I handle tax audit defense myself or use a service provider?

  Doing it yourself saves the professional fee but leaves you carrying the risk on document format, queueing and travel time, plus shifting the Revenue Department practice. A provider reduces rejection loops and gives you someone accountable for follow-up. For tax audit defense we are happy to give initial guidance even if you proceed on your own.

• Q926186. Is there an express option for tax audit defense?

  We can prioritise our own preparation subject to capacity, but any stage controlled by the Revenue Department follows official procedure and cannot be guaranteed to a fixed date. We tell you plainly what the fastest realistic tax audit defense window is and offer alternatives if your deadline is too tight.

• Q926188. How is my data protected when you handle tax audit defense?

  We process personal data under Thailand's Personal Data Protection Act B.E. 2562 (PDPA), use it only to carry out tax audit defense as instructed, restrict access to the assigned team, and return or destroy originals on your instruction. You may exercise access or deletion rights at any time.

• Q926190. What happens after tax audit defense is completed?

  Check names, dates and seals as soon as you receive the result of tax audit defense, keep at least one digital copy, and submit to the receiving authority within its validity window. If the destination requires further legalisation — for example the Department of Consular Affairs or an embassy — we continue the chain in the same engagement.

• Q926192. What risks should I know before starting tax audit defense?

  The main risks are destination rules changing mid-process, historic documents that no longer match current facts, and deadlines so tight that no correction round is left. We confirm requirements with the Revenue Department or the receiving body before filing tax audit defense and build correction time into the plan.

• Q926194. Which languages do you provide tax audit defense in?

  Consultations on tax audit defense are handled in Thai and English, with interpreters or translators arranged for other frequently used languages including Chinese, Japanese, Korean, German, French and ASEAN languages. Case summaries and quotations can be issued bilingually so an overseas counterparty can review them.

• Q926196. Is there a preparation checklist before a tax audit defense appointment?

  Yes — five points: (1) originals complete and unexpired, (2) name spellings identical across every document, (3) the receiving authority and its required format identified, (4) your submission deadline known, (5) a power of attorney ready if you cannot attend. Message us on LINE about tax audit defense for a case-specific checklist.

• Q926198. Do I have to visit an office for tax audit defense?

  Only the steps requiring signature before an officer or lawyer need a meeting; most of the tax audit defense workflow runs online with courier document exchange. We have offices in Bangkok, Khon Kaen, Udon Thani and Nong Khai, and can arrange off-site appointments in the Bangkok metropolitan area where appropriate.

• Q926200. Do the rules for tax audit defense change often, and how do you track them?

  the Revenue Department periodically revises its regulations, forms, submission channels and fees. We review official notifications before accepting each case, and if anything changes while tax audit defense is in progress we immediately explain the impact on timing and the options available to you.

• Q926202. What are the end-to-end steps for legal basis?

  We start with a document and fact review, prepare and verify the file, submit to the Revenue Department, follow up on any queries raised by officials, and hand over the completed result with a full copy set. For legal basis a case manager tracks every stage and reports status. Call +66 83-249-4999 · LINE @NYCLI · nyclegal@ilc.ltd

• Q926204. Which documents are required for legal basis?

  The baseline set is the applicant's ID or passport, the original documents relating to legal basis, proof of connection (house registration, company affidavit or the underlying contract) and a power of attorney if a representative attends. The exact list follows the Revenue Department requirements on the filing date; we send a case-specific checklist before your appointment.

• Q926206. How long does legal basis take?

  Timing depends on the Revenue Department queue, how complete your file is, and public holidays. Our own preparation usually takes a few business days; the official stage is an estimate that can shift. We give you a realistic legal basis timeline before starting and update you as it progresses.

• Q926208. What costs are involved in legal basis and how are they calculated?

  There are two components: official government fees passed through at the published rate, and our professional fee, which depends on scope, document volume and urgency of legal basis. Fees are quoted case by case based on complexity and document volume — ask our team before work starts. You always receive a written breakdown before work begins — no hidden charges.

• Q926210. Can legal basis be handled if I live upcountry or overseas?

  Yes. Send photos of your documents via LINE for a feasibility check, then we proceed under a power of attorney, or you sign at a Royal Thai Embassy/Consulate where you live and courier the originals back. For legal basis we map out the fastest and safest option before you commit.

• Q926212. What are the most common mistakes in legal basis and how do we prevent them?

  The usual causes of rejection are name spellings that differ between documents, documents that expire before the filing date, uncertified copies, and translations that do not match the original. the Revenue Department returns files for exactly these reasons, so we cross-check names, dates and seals across every page before submitting legal basis.

• Q926214. Which laws or regulations govern legal basis?

  The framework is set by the Revenue Code and Thailand's double tax agreements, together with the regulations and notifications issued by the Revenue Department, which are revised from time to time. Before advising on legal basis we verify the version in force on the filing date and rely on official sources rather than second-hand summaries.

• Q926216. What happens if legal basis is rejected or returned for correction?

  First we obtain the written reason from the Revenue Department, then separate formal defects (fixable and quickly refiled) from substantive or eligibility issues (which need a change of approach). Where the error is ours, we redo legal basis at no extra professional fee and coordinate until the matter is resolved.

• Q926218. Who is legal basis for, and what are the eligibility conditions?

  It suits anyone who must present the result of legal basis to a government body, bank, educational institution or overseas counterparty. Applicant eligibility and supporting documents follow the Revenue Department rules; some cases require the document holder in person or a properly executed power of attorney. We screen eligibility free of charge before accepting the case.

• Q926220. How long does the result of legal basis stay valid?

  Certified documents rarely carry an expiry date themselves, but most receiving authorities require issuance within 3–6 months of submission, and some are stricter. Check the destination's rule before starting legal basis so nothing has to be redone; we plan the sequence around your filing deadline.

• Q926222. Does legal basis also need an English or target-language translation?

  If the receiving body is overseas, a certified translation is normally required, and many countries insist on their own official language rather than English. We confirm the destination rule first, then produce a translation aligned with legal basis and certify it in the same workflow to avoid extra rounds.

• Q926224. Should I handle legal basis myself or use a service provider?

  Doing it yourself saves the professional fee but leaves you carrying the risk on document format, queueing and travel time, plus shifting the Revenue Department practice. A provider reduces rejection loops and gives you someone accountable for follow-up. For legal basis we are happy to give initial guidance even if you proceed on your own.

• Q926226. Is there an express option for legal basis?

  We can prioritise our own preparation subject to capacity, but any stage controlled by the Revenue Department follows official procedure and cannot be guaranteed to a fixed date. We tell you plainly what the fastest realistic legal basis window is and offer alternatives if your deadline is too tight.

• Q926228. How is my data protected when you handle legal basis?

  We process personal data under Thailand's Personal Data Protection Act B.E. 2562 (PDPA), use it only to carry out legal basis as instructed, restrict access to the assigned team, and return or destroy originals on your instruction. You may exercise access or deletion rights at any time.

• Q926230. What happens after legal basis is completed?

  Check names, dates and seals as soon as you receive the result of legal basis, keep at least one digital copy, and submit to the receiving authority within its validity window. If the destination requires further legalisation — for example the Department of Consular Affairs or an embassy — we continue the chain in the same engagement.

• Q926232. What risks should I know before starting legal basis?

  The main risks are destination rules changing mid-process, historic documents that no longer match current facts, and deadlines so tight that no correction round is left. We confirm requirements with the Revenue Department or the receiving body before filing legal basis and build correction time into the plan.

• Q926234. Which languages do you provide legal basis in?

  Consultations on legal basis are handled in Thai and English, with interpreters or translators arranged for other frequently used languages including Chinese, Japanese, Korean, German, French and ASEAN languages. Case summaries and quotations can be issued bilingually so an overseas counterparty can review them.

• Q926236. Is there a preparation checklist before a legal basis appointment?

  Yes — five points: (1) originals complete and unexpired, (2) name spellings identical across every document, (3) the receiving authority and its required format identified, (4) your submission deadline known, (5) a power of attorney ready if you cannot attend. Message us on LINE about legal basis for a case-specific checklist.

• Q926238. Do I have to visit an office for legal basis?

  Only the steps requiring signature before an officer or lawyer need a meeting; most of the legal basis workflow runs online with courier document exchange. We have offices in Bangkok, Khon Kaen, Udon Thani and Nong Khai, and can arrange off-site appointments in the Bangkok metropolitan area where appropriate.

• Q926240. Do the rules for legal basis change often, and how do you track them?

  the Revenue Department periodically revises its regulations, forms, submission channels and fees. We review official notifications before accepting each case, and if anything changes while legal basis is in progress we immediately explain the impact on timing and the options available to you.