Thailand's standard corporate income tax (CIT) rate is 20% of net profit. Small and medium enterprises (paid-up capital not exceeding THB 5 million and revenue not exceeding THB 30 million) benefit from a progressive scale: 0% on the first THB 300,000 of net profit, 15% on THB 300,001-3,000,000, and 20% above that. BOI-promoted companies (in targeted sectors like tech, EVs, and regional headquarters) can receive CIT holidays of 3-13 years plus import duty exemptions. Thailand also implemented a 15% global minimum tax (Pillar Two top-up tax) for large multinational groups from 2025, aligning with OECD BEPS rules.
Corporate tax structure and SME/BOI incentives materially affect the decision to incorporate a Thai limited company versus operating as a branch, and whether BOI promotion is worth pursuing for a relocating entrepreneur's business.
Key Facts
Standard CIT rate: 20% of net profit.
SME progressive scale (paid-up capital ≤ THB 5m, revenue ≤ THB 30m): 0% on first THB 300,000; 15% on THB 300,001-3,000,000; 20% above THB 3,000,000.
BOI-promoted businesses can get CIT holidays of 3-13 years depending on activity and location, plus import duty exemptions on machinery and raw materials.
A 15% global minimum tax (Pillar Two) applies to Thai-based entities of multinational groups with consolidated revenue over EUR 750 million, effective from accounting periods starting 2025.
Foreign companies not registered in Thailand but earning Thai-sourced income are generally subject to withholding tax rather than full CIT filing.
Steps
Determine applicable rate — Check whether the company qualifies as an SME under the capital/revenue thresholds, or whether BOI promotion applies.
File half-year and annual returns — Companies file a mid-year estimate (PND 51) and annual return (PND 50) with the Revenue Department.
Consider BOI application — For qualifying activities, apply for BOI promotion before or shortly after incorporation to lock in tax holidays.
Timelines
Mid-year corporate tax return (PND 51): within 2 months of the end of the first 6 months of the accounting period
Annual corporate tax return (PND 50): within 150 days of the end of the accounting period
Required Documents
Company registration certificate and Tax ID
Audited financial statements (for annual filing)
VAT registration certificate if applicable
BOI promotion certificate (if applicable)
Common Mistakes
Assuming the 20% flat rate applies to all companies — SMEs under the capital/revenue thresholds get a more favorable progressive scale on the first THB 3 million of profit.
Missing the mid-year PND 51 estimated filing, which triggers penalties even before the annual return is due.
Not realizing BOI tax holidays require the promoted activity and BOI certificate to be secured before certain income/investment is booked.