I. The Era of Digital Auditing Has Arrived: How RD Finds Your Problems

In the past, Thai tax audits relied heavily on manual spot checks and whistleblowing, but between 2024 and 2025, RD completed the integration of three key technologies, fundamentally changing the audit model:

In recent years, the Thai Inland Revenue Department has been actively working towards cross-agency data integration, and has repeatedly stated publicly that it will leverage technology and AI to improve review efficiency and enhance the ability to compare submitted documents. Industry experts generally observe that significant discrepancies between the import/export amounts, BOI-declared production volume, and financially declared revenue of foreign-invested enterprises may become important reference points for the tax authorities when selecting cases for audits in the future.

Since its rollout in 2021, the coverage of Thailand's e-Tax Invoice system has been steadily increasing. RD is now able to perform large-scale comparisons of historical invoice data for enterprises, including abnormal fluctuations in sales, repeated high-value transactions with the same buyer, and verification of the seller's identity for input invoices.

According to official RD data, since 2025, the selection of tax audit cases has incorporated machine learning models to score foreign-invested manufacturing enterprises based on profit margin trends, related-party transaction ratios, and consistency with their declarations. Enterprises with high-risk scores will be placed on a priority audit list without waiting for a report.

II. Three Core Compliance Risks for Foreign-Invested Enterprises

When a Thai subsidiary pays management service fees, technology licensing fees, software usage fees, etc., to its overseas parent company or group enterprise, Thai tax law requires withholding tax at the source, with rates ranging from 5% to 15% depending on the nature of the transaction. In practice, some foreign companies fail to adequately assess the Thai tax law's definition of "service delivery location" when setting up intra-group expenses, resulting in the underreporting of withholding items. The 2026 RD audit will focus on such cross-border payments, and the tax owed will be retroactive for three to five years, with penalties plus interest resulting in a substantial burden.

Thailand's standard VAT rate is 7% (currently under reduction, the statutory rate is 10%), with exports subject to a zero tax rate and eligible for refunds. However, since 2025, the RD has implemented stricter document review for VAT refund applications, requiring foreign-invested enterprises to provide a complete chain of export documents (including e-invoices, bills of lading, and bank transfer records). Incomplete applications will be rejected for resubmission, extending the refund process to over six months. Foreign-invested enterprises' finance departments should prepare complete document chains in advance and consider setting up a refund tracking mechanism to avoid fund backlogs.

Thailand's Revenue Code stipulates that any multinational conglomerate (with consolidated annual revenue exceeding 28 billion Thai Baht, approximately NT$24 billion) with a group entity in Thailand must submit a CbCR (Combined Tax Code for Taxes) to the location of the ultimate parent company and notify the Thai RD (Revenue Department). 2026 will be the first full year of implementation, and the RD is expected to initiate audits of the completeness of the declarations. Penalties for incorrect or incomplete declarations can reach up to 200,000 Thai Baht under Thai law, and failure to declare is itself a violation, regardless of any tax differences.

III. Comparison of the audit environment between Taiyue and other markets: Which market faces greater pressure?

In terms of overall audit intensity, Vietnam's GDT has rapidly caught up with Thailand in recent years in its proactive approach to transferring pricing audits; however, Thailand's RD currently holds a lead in the completeness of its digital audit infrastructure—it has a higher degree of cross-agency data integration and a more mature AI-based case selection model. For foreign-invested enterprises operating in both countries, consistent related-party transaction pricing policies and documentation standards should be adopted in both Thailand and Vietnam to avoid contradictory figures reported in both jurisdictions, which could trigger audits from both tax authorities simultaneously.

IV. Prevention Recommendations: A Two-Pronged Approach Including Financial Systems and Local Advisors

In response to Thailand's upgraded digital audits in 2026, foreign companies should simultaneously advance their strategies on two levels:

At the system level, an ERP system with a tax filing module was introduced to ensure that accounting data for sales, procurement, and withholding taxes can automatically generate filing documents in RD format, reducing errors caused by manual processing; at the same time, an electronic invoice archiving mechanism was established to ensure that the documents required for VAT refunds are complete and accessible.

At the advisory level, it is recommended to engage a local Thai tax advisor annually for a tax health check, specifically to verify cross-border withholding, VAT declaration consistency, and CbCR declaration completeness, eliminating potential risks before an audit is selected.

Digitalization makes Thai tax audits smarter, but it also makes compliance management more efficient. Foreign companies that proactively embrace digital tools will be the least likely to be selected in the audit wave.