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Most Thai forex traders don’t file tax returns on their trading profits. That’s increasingly a problem. The Revenue Department’s digital infrastructure has improved significantly, AMLO’s transaction monitoring has expanded, and Thai banks are now required to flag cross-border capital flows more aggressively than before. The window for treating forex income as invisible is closing.
Are Forex Profits Taxable in Thailand?
Yes. Forex trading profits are assessable income under Section 40 of the Thai Revenue Code — specifically Section 40(8), which covers income from any activity not already classified under Sections 40(1) through 40(7). This includes gains from foreign exchange trading conducted through international brokers.
The fact that your broker is based in London, Sydney, or Cyprus and sends you no Thai tax form does not exempt you. Thai residents are taxed on assessable income from all sources, including income derived from abroad, if that income is brought into Thailand in the same tax year it is earned. That last condition — same tax year — was a loophole that allowed some traders to defer recognition by leaving funds offshore. A 2024 Revenue Department ruling tightened this significantly, extending the reporting obligation to income brought into Thailand regardless of when it was earned.
How to Calculate What You Owe
Net realized gains are what matters. If you opened a EUR/USD trade, held it for three days, and closed it at a profit, that profit — converted to THB at the BOT reference rate on the day you realized it — is the assessable income. Unrealized gains (open positions) are not taxed until you close the trade.
Losses are treated symmetrically: realized losses reduce assessable income in the same tax year. If you had total realized gains of 500,000 baht and realized losses of 200,000 baht in 2026, you report 300,000 baht as net assessable income from forex trading.
Expenses that are directly and wholly necessary for generating the income can be deducted — this could include subscription fees for trading platforms, data feeds, or educational material directly related to your trading activity. Maintain receipts.
What Tax Rate Applies
Forex income stacks with all other assessable income for the year. Personal income tax in Thailand is progressive: 0% up to 150,000 baht, 5% from 150,001 to 300,000, 10% from 300,001 to 500,000, 15% from 500,001 to 750,000, 20% from 750,001 to 1 million, 25% from 1 to 2 million, 30% from 2 to 5 million, and 35% above 5 million baht.
If you have an annual salary of 600,000 baht and net forex gains of 300,000 baht, your total assessable income is 900,000 baht (before personal deductions). The incremental tax on the 300,000 baht of forex gains would be taxed at the 20–25% band depending on where your salary already puts you in the brackets.
Which Tax Form to Use
Individuals with assessable income beyond salary use Form PND 90 (ภ.ง.ด. 90). The filing deadline is March 31 of the following year (e.g., your 2026 income is reported by March 31, 2027). The Revenue Department’s e-filing system (e-Filing at rd.go.th) accepts submissions online. If your total assessable income is below the taxable threshold (150,000 baht after deductions), you may not owe any tax, but filing is still the correct practice if you have assessable income above 60,000 baht from non-salary sources.
Practical Steps for Thai Forex Traders
Step one: Export your trade history from your broker account in CSV or PDF format at the end of each tax year. IC Markets, FxPro, Exness, and other brokers that serve Thai clients all provide this. Step two: Calculate total realized gains and losses. Most trading platforms have a realized P&L summary — use that figure. Step three: Convert the net gain to THB using the BOT’s average reference rate for the year, or the rate on the specific date of each trade if you want precision. Step four: Add the net forex income to your PND 90 form under the appropriate Section 40(8) income category. Step five: Apply personal deductions (standard 60,000 baht personal allowance, plus dependents if applicable) and calculate the net taxable income. Step six: File by March 31.
What This Means for Thai Traders
Two things are making non-filing riskier than before. First, the BOT’s expanded AML monitoring — which now tracks USDT flows and flags large cash deposits — creates a data trail that the Revenue Department can access. Second, Thai banks are increasingly filing currency transaction reports (CTRs) on international transfers, which creates a record that can be cross-referenced with tax filings. If you’re routing significant forex profits through international wire transfers back to Thailand, those flows are visible.
Filing is not just the legal obligation — it’s also protection. A trader who files consistently, even for years with modest profits, has a documented track record that demonstrates compliance. A trader who hasn’t filed and then faces a Revenue Department inquiry has a much more difficult position to explain.
If your forex trading volume is significant and you haven’t been filing, consulting a Thai tax advisor before filing retroactively for prior years is the right move. The Revenue Department does have voluntary disclosure provisions, and coming forward proactively is treated better than being discovered.
