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If you’re still holding LTF units that have been sitting idle since the fund was phased out in 2020, the Thai government has handed you an interesting exit ramp. The Thailand ESG Extra Fund — Thai ESGX — launched its IPO window from 2 May to 30 June 2025, and the swap window may reopen for late-stage participants. The headline benefit: switching your LTF units lets you reclaim up to ฿500,000 in tax deductions, spread across 2025 to 2029.
That’s a real number for anyone in the 25% or 30% tax bracket. But the swap isn’t automatic, and the lock-up rules have teeth. Here’s what you actually need to weigh up before deciding.
What Thai ESGX is, in plain terms
Thai ESGX is a sustainability-themed mutual fund that must keep at least 80% of its NAV in ESG-rated Thai assets, with at least 65% in equities listed on SET or mai that carry an ESG rating. It can also hold sustainable debt and tokenized green assets. Up to 20% can sit in non-ESG Thai stocks to give the fund manager some flexibility.
What makes it different from regular Thai ESG funds is the tax mechanic. There are three separate deduction buckets stacked on top of each other, totaling up to ฿900,000 in a single year for high earners who maximize every category.
The three tax deduction buckets
First, new Thai ESG fund investments give you up to 30% of assessable income, capped at ฿300,000 per year. Second, new Thai ESGX subscriptions during the IPO window give another ฿300,000 deduction on top, completely separate from the regular Thai ESG limit. Third — and this is the switch path — moving existing LTF units into Thai ESGX gives a further ฿500,000 deduction, spread out as ฿300,000 in 2025 and ฿50,000 per year from 2026 to 2029.
The catch on the switch: it’s all-or-nothing. You can’t switch some LTF units and leave the rest. You have to move every LTF unit across every asset management company you hold units with, or the tax benefit doesn’t apply.
The five-year lock-up reality
Switched units must be held for at least five consecutive years from the switch date, calculated day-to-day. If you switched units on 1 June 2025, they unlock on 1 June 2030. Sell earlier and you owe back the tax you saved, plus a 1.5% monthly surcharge from the Revenue Department.
That’s the part most people underestimate. The LTF units you’re moving are already old — most LTFs you’d be holding now are from 2019 or earlier, and you’ve been waiting for them to be useful. Locking them up for five more years just to get a tax break against future income is a real cost, especially if your income trajectory is flat.
When the switch makes sense
Roughly, the switch pays off if all three are true: you have meaningful LTF units (the larger, the better), your annual taxable income is high enough to use the ฿50,000 yearly deduction from 2026-2029 (that requires roughly ฿200,000+ in taxable income at the 25% bracket), and you don’t need the LTF capital for anything in the next five years.
If your LTF balance is under ฿100,000, the math gets thin once you account for the lock-up cost and any redemption fees. And if your income is dropping — say you’re approaching retirement — those future deductions matter less.
What’s happening in 2026
After the 2025 IPO window closed on 30 June 2025, Thai ESGX reopened for general investment in 2026 with the standard ฿300,000 cap, same as regular Thai ESG. The big LTF-switch window with the extended ฿500,000 cap was the 2025 event — but the regular ฿300,000 cap remains usable each year through to 31 December 2026.
If you missed the 2025 LTF switch, you can still invest in Thai ESGX fresh and get the ฿300,000 annual deduction. Worth doing if you’re already maxing out RMF and SSF and want more tax-deductible room.
How to act on this
Check your LTF positions across every asset management company you’ve ever used — SCB, Bualuang, Krungsri, K-Asset, MFC, etc. People often forget about old LTF buys from a decade ago. Total the unit count, then ask your bank or asset manager to model the switch.
If the numbers work, the switch is mechanical: file the transfer request, hold the units for five years, and claim the deductions in your annual filings from 2026 onward. The Revenue Department guidance on Thai ESGX is straightforward, and most banks have dedicated teams for this product because the demand surprised them.
One last note: the off-shore portion of any Thai ESG or ESGX fund usually isn’t currency-hedged. Given the baht’s recent moves against the dollar — USD/THB sat near 32.6 in mid-May 2026 — currency risk on the foreign portion is real. Most Thai ESGX funds keep it under 20% of NAV, but worth checking the prospectus.
