The State of ESG Disclosure in Thailand
265 SET-listed companies now hold an ESG rating — a record. Yet only 18% track their Scope 3 emissions, and just 38% of those disclosing GHG data have it independently assured. As the market moves from SET’s own ratings to FTSE Russell scores in 2026, this is where Thai disclosure actually stands — and where the points are still on the table.
A record year — and the last of its kind
In its final year, SET’s own ESG Ratings covered 265 companies (~70% of SET + mai market cap). The top band nearly doubled year-on-year — a signal of genuine progress, and of a framework being retired at its high-water mark.
SET ESG Ratings 2025 — distribution
AAA rose from 56 (2024) to 102 (2025) as total coverage grew and more mid-caps qualified — read alongside the depth data in section 02 before reading it as uniformly higher quality. The live SET register lists 260 rated securities as of 12 Jul 2026 (99 AAA / 78 AA / 67 A / 16 BBB); the delta to the December announcement reflects delistings since.
The climb: 2022–2025
Where the ratings actually sit — by industry group
| Industry group | Rated / listed | Rated % | of which AAA | Disclose GHG data |
|---|---|---|---|---|
| Agro & Food | 35 / 84 | 42% | 11 | 52% |
| Financials | 33 / 80 | 41% | 13 | 31% |
| Resources (Energy) | 26 / 72 | 36% | 17 | 49% |
| Industrials | 42 / 147 | 29% | 10 | 31% |
| Technology | 19 / 71 | 27% | 7 | 35% |
| Services | 51 / 199 | 26% | 19 | 32% |
| Property & Construction | 41 / 208 | 20% | 19 | 20% |
| Consumer Products | 13 / 70 | 19% | 3 | 24% |
Two patterns the market-wide numbers hide: Agro & Food and Financials lead on rating penetration (~42%), while Property & Construction carries many AAA names yet only 20% of the group discloses GHG data — and Consumer Products trails on both. GHG-disclosure rate (amber) runs well below rating penetration in most groups: the rating is easier to earn than the emissions data behind it.
SET retires its four-band AAA–BBB system and begins publishing FTSE Russell ESG Scores — a continuous 0.0–5.0 scale, disclosed for every assessed company (no more “pass to be listed”). The methodology widens to three pillars, 14 themes and ~125 indicators applied per Thai issuer. The 2025 SET ratings remain the ThaiESG-fund investable universe through December 2026 — so this year’s disclosure carries into next year’s eligibility.
The depth gap beneath the ratings
Coverage is up; depth is not. Three numbers define how far Thai disclosure has to travel before a global methodology scores it on evidence rather than intent.
From the register itself
Just ~32% of all listed companies carry SET’s own “discloses GHG management data” flag — while 68% of ESG-rated companies do. The rated pool is roughly twice as likely to disclose as the market at large; the tail is where the silence sits.
34% of SET main-board companies hold an ESG rating (240 of 702) — but only 9% of mai companies do (20 of 229). The disclosure gap is also a market-segment gap, and it widens as you move down the cap scale.
Among Thailand’s 61 largest listed companies, 80% disclose some GHG data — but only 12% reference TCFD, and barely a third assure their numbers. The pattern is consistent across studies: Thai issuers report best on social and human-rights topics and weakest on environmental — the inverse of most global markets, and precisely the axis FTSE Russell and IFRS S2 weight most heavily.
This is the gap that a rating band hides. A company can hold AA on the retiring SET scale and still lack an assured inventory, a Scope 3 boundary, or a costed pathway — the exact evidence a 0.0–5.0 FTSE score rewards.
The regulatory turn is already dated
The disclosure Thailand does voluntarily today becomes mandatory, assured and globally-benchmarked on a fixed timetable.
The Thai SEC’s ISSB roadmap requires SET50 companies to disclose under IFRS S1/S2 from FY2026 (first reports in 2027): climate-first, with delayed Scope 3 and limited assurance required on Scope 1 & 2. The reliefs themselves concede today’s readiness gap.
SET replaces its own ratings with FTSE Russell ESG Scores, published for every assessed company. Non-disclosure no longer means “unrated” — it means a visible low score, estimated from your absence of data.
ESG disclosure has been mandatory within Form 56-1 One Report on a comply-or-explain basis since FY2021. The structure exists; the evidence behind it is what the next phase tests.
26 Thai companies held SBTi-validated targets by mid-2025, up from 11 at end-2023 (+136%). Validated pathways remain the exception — and the clearest separator between a claim and a credible target.
Six gaps that cost the most points
Across the studies, the same weaknesses recur. None require a new strategy — only disclosure that matches what the company already does.
- 01Scope 3 is the cliff-edge — Disclosure collapses from 41% (Scope 1 & 2) to 18% (Scope 3). Value-chain accounting is the single largest data gap — and the SEC’s own roadmap grants Scope 3 relief, tacitly conceding how few are ready.
- 02Assurance is thin — Even among large disclosers, only ~38% obtain external assurance on GHG data. Most numbers reach investors unverified — the fastest-eroding source of rater confidence.
- 03Climate lags social & governance — Unusually for a global market, Thai issuers disclose best on human-rights and social, weakest on environmental — with only 12% of the largest referencing TCFD. Climate governance is asserted more than evidenced.
- 04Targets without pathways — With 26 SBTi-validated companies nationwide and 12% TCFD uptake, most “net-zero” claims lack a validated reduction pathway, a rigorous base year, or quantified scenario analysis.
- 05A two-tier market — 34% of SET main-board companies are rated versus just 9% on mai — and only ~32% of listed names carry SET’s GHG-disclosure flag at all. The largest issuers produce comprehensive reports; the long tail is materially behind on both scope and quality.
- 06The bilingual seam — Raters read the English submission; the Thai 56-1 One Report prevails legally. Terminology drift between the two versions — and thin English disclosure — quietly costs points no methodology change will recover.
The top tier proves it’s reachable
Thailand is not short of leaders — the distance is between the leading cohort and the median issuer.
These companies score because they close the same six gaps: assured inventories, Scope 3 boundaries, validated targets, quantified scenarios, and disclosure that reads cleanly in both Thai and English. The methodology change in 2026 does not move the bar for them — it simply makes the distance to everyone else legible.
Method & sources
This brief compiles publicly reported figures. Each is flagged hard (primary regulator / standards body / named study with sample size), reported (credible secondary reporting of a primary figure), or estimate (directional or proxy). We do not publish figures we could not source.
| Finding | Source | Confidence | |
|---|---|---|---|
| SET “List of Thai ESG Securities” register (12 Jul 2026): 260 rated securities (99 AAA / 78 AA / 67 A / 16 BBB); ~32% of listed carry the GHG-disclosure flag; SET 34% vs mai 9% rated; per-industry-group breakdown | SET official register, Othello analysis | hard | link |
| 265 firms rated in 2025; distribution 102/80/67/16; ~70% of SET+mai market cap | ASEAN Exchanges / SET media release, Dec 2025 | reported | link |
| 228 firms rated in 2024 (56/80/71/21) | SET announcement via Kaohoon, Dec 2024 | hard | link |
| 193 firms in 2023 (first year of AAA–BBB bands); 170 THSI in 2022 | SET news / Thailand Business News | reported | link |
| SET retires its own ratings; publishes FTSE Russell ESG Scores (0.0–5.0) from 2026; 2025 ratings define the ThaiESG universe through Dec 2026 | ASEAN Exchanges; Optiwise; SET Sustainability FTSE guidelines | hard | link |
| 41% of SET firms collect Scope 1 & 2 data; 18% track Scope 3 | SET data, reported by Nation Thailand | reported | link |
| 80% of the 61 largest listed firms disclose GHG data; of those only 38% obtain external assurance; 12% reference TCFD | World Bank / Thai SEC / Chronos Sustainability assessment, Dec 2023 (n=61) | hard | link |
| SET50 companies must disclose under IFRS S1/S2 from FY2026 (first reports 2027) — climate-first, delayed Scope 3, limited assurance on Scope 1 & 2 | Thai SEC ISSB roadmap consultation, 2025 | hard | link |
| 26 Thai companies held SBTi-validated targets by Q2 2025, up from 11 at end-2023 | Science Based Targets initiative dashboard | reported | link |
| 13 Thai companies in DJSI World, 26 in DJSI Emerging Markets; ~30 in the S&P Global Sustainability Yearbook | S&P Global CSA, via The Nation | reported | link |
| ESG disclosure mandatory within Form 56-1 One Report on a comply-or-explain basis since FY2021 | Thai SEC | hard | link |
Notes: the rating counts, the per-industry-group breakdown, the ~32% GHG-disclosure flag and the SET-vs-mai split are computed by Othello directly from SET’s official “List of Thai ESG Securities” register (extracted 12 Jul 2026; 260 rated of ~931 listed) — this is primary data. The 265-company figure and the AAA growth are from the December 2025 SET announcement; the small delta to 260 reflects delistings since. The 41% / 18% Scope 1-2-3 depth split is sourced to SET data as reported by Nation Thailand (flagged reported) and measures Scope-level depth, distinct from SET’s binary GHG-disclosure flag. Assurance (38%), GHG disclosure (80%) and TCFD (12%) are from the World Bank / Thai SEC / Chronos assessment of the 61 largest listed companies (Dec 2023) and generalise to that cohort, not the full market.
The market average is 18% on Scope 3. Where does your disclosure actually stand?
We run an FTSE-style Report Card on your latest report — scored against the 2026 methodology, sector-adjusted, with the specific gaps that separate your disclosure from your peers’. One hour, under NDA. Or start free with the self-scorecard.
Related: the flagship State of Thai Corporate Climate Disclosure 2026 report · the sector FTSE 2026 playbooks · the Bilingual Disclosure Handbook · the CFO Handbook