SET ESG Ratings 2026: Criteria & FTSE Russell Shift

For nearly a decade, the SET ESG Ratings were the benchmark of corporate sustainability for companies listed on the Stock Exchange of Thailand. From 2026 they are being retired and replaced by FTSE Russell ESG Scores. This guide explains what the SET ESG Ratings measured, how they were assessed, the latest results, and what the shift to a global rating model means for every listed Thai company.

What are the SET ESG Ratings?

The SET ESG Ratings (formerly the Thailand Sustainability Investment, or THSI, list) were an annual assessment run by the Stock Exchange of Thailand to recognise listed companies with strong environmental, social and governance practices. A company that qualified could use the rating in investor communications, and the ratings fed Thailand’s sustainable-investment indices and the growing pool of ESG funds.

How were the SET ESG Ratings assessed?

Assessment was questionnaire-based. Companies completed a detailed sustainability questionnaire, and the SET scored responses across the environmental, social and governance dimensions, with corporate-governance and risk screening applied on top. Qualifying companies received a tiered rating (from AAA down to C). Because the process relied on what companies reported in the questionnaire, preparation and internal data quality largely determined the outcome.

SET ESG Ratings 2025 results

In the 2025 assessment, 265 listed companies qualified for a SET ESG Rating — up from 219 the year before — with higher average scores across all three ESG dimensions. The SET framed the improvement as evidence that Thai issuers were ready for the transition to a global benchmarking model.

Why SET is replacing the ratings with FTSE Russell ESG Scores (2026)

From 2026 the SET will publicly announce FTSE Russell ESG Scores and discontinue the SET ESG Ratings. The change is fundamental, not cosmetic. Where the old ratings were built from a private questionnaire, FTSE Russell scores are derived only from publicly disclosed information — your annual report, your sustainability report and your corporate website. FTSE Russell applies a three-tier structure of 3 pillars, 14 themes and over 300 indicators, with Thai companies assessed on roughly 125 indicators on average. We cover the mechanics in detail in our guide to the SET’s move to FTSE Russell ESG Scores in 2026.

Questionnaire vs public disclosure: the core shift

The most important thing to understand about the transition is where the rater gets its information. The old SET model was a disclosure-to-the-rater model: you filled in a questionnaire, and a strong internal team could present the company well even if its public reporting was thin. The FTSE Russell model is a disclosure-to-the-public model: the rater reads only what any investor can read, and nothing you say privately counts. A company that historically leaned on a well-drilled questionnaire process, without publishing the underlying evidence, can see its score fall even though nothing about its actual sustainability performance has changed.

This reframes the whole exercise. Under FTSE Russell, improving your score is not about answering questions better — it is about ensuring every material practice you already have is publicly documented, in English, in a place the rater looks. Many Thai issuers discover they are doing the work but not disclosing it, and the gap between practice and published evidence is where points are quietly lost.

What changes for listed companies

The single biggest shift is this: you can no longer “manage” your score through a questionnaire. If a data point is not published — clearly, and in English — it does not count. Three consequences follow for every SET- and mai-listed issuer:

• English disclosure now drives the score. FTSE Russell assesses public information; thin or Thai-only disclosure leaves indicators unscored.
• Your annual report and 56-1 One Report become rating documents. The ESG content inside them is read directly by the rater, so quality and completeness matter more than ever.
• Materiality must be defensible. A robust double materiality assessment determines which topics you disclose against — and therefore which indicators you can score on.

How the score connects to IFRS S1/S2 and the 56-1 One Report

The FTSE Russell transition does not sit apart from Thailand’s wider disclosure agenda — it is the rating-facing side of the same shift toward high-quality public reporting. The climate and sustainability content that Thailand is phasing in under the IFRS S1 and S2 standards lands in the same 56-1 One Report that FTSE Russell reads to build your score. In other words, the regulatory filing and the ESG rating are increasingly fed by one body of disclosure. Strong, consistent, bilingual reporting improves both at once; a thin or contradictory disclosure weakens both. Treating IFRS S1/S2 preparation and FTSE readiness as a single programme, rather than two projects, is the efficient path.

How to prepare for the FTSE Russell transition

• Map the FTSE Russell indicators against your current public disclosure and find the gaps.
• Run or refresh a double materiality assessment so your disclosure covers the topics that matter.
• Strengthen the ESG section of your annual report and 56-1 One Report — and publish it in high-quality English, not a rushed translation.
• Ensure every material data point appears in a publicly accessible place: the report, the sustainability report, or the corporate website.
• Treat English-language disclosure as a scored asset, with the same rigour as your financial statements.

The bilingual risk hiding in a global rating model

Because FTSE Russell scores the English-language version of your disclosure, the quality of that English becomes part of your score — not a presentational afterthought. A Thai issuer can do everything right operationally and still lose indicators because a policy is described vaguely in English, a target is worded so it no longer reads as a firm commitment, or a metric is defined differently in the English report than in the Thai original. When the two language versions drift, the rater scores the weaker English text, and the company is marked down for a gap that exists only in translation. Disclosure-grade, ISO 17100 bilingual work — reconciling both versions against one agreed meaning — protects the score you have actually earned.

Frequently asked questions

Are the SET ESG Ratings still valid in 2026? The SET is moving to publicly announcing FTSE Russell ESG Scores from 2026 and discontinuing the SET ESG Ratings. Companies should plan around the FTSE Russell methodology going forward.

Do I need an English sustainability report to score well? In practice, yes. FTSE Russell scores public disclosure, and English is the working language of global ratings and investors. Information disclosed only in Thai is at risk of going unscored.

Where does translation fit in? Your FTSE Russell score is calculated from the public, English-language documents you publish. Disclosure-grade bilingual translation of the annual report, 56-1 One Report and sustainability report is therefore part of the score itself — not an afterthought.

Will our score change even if our practices haven’t? It can. Because the model reads only public disclosure rather than a questionnaire, a company that performs well but publishes little may score lower than before — which is why closing the gap between practice and published evidence is the priority.

Turn disclosure into a higher score

Othello International combines ESG advisory with disclosure-grade bilingual translation built specifically for SET-listed companies — the only combination that addresses both what you disclose and how clearly it reads to a global rater. To benchmark your readiness for the FTSE Russell transition, talk to our team.

Related ESG guides

• Scope 1, 2 & 3 GHG Inventory for Thai Companies (TGO-Aligned)
• Double Materiality Assessment, Explained for Thai Issuers
• SET Moves to FTSE Russell ESG Scores in 2026: What SET-Listed Boards Must Do
• GRI vs SASB vs IFRS S1/S2: ESG Reporting Frameworks Explained (2026)
• 56-1 One Report Deadline 2026: Thailand Filing Dates & Bilingual Requirements

Related Othello services

• Ratings Submissions
• Sustainalytics Engagement
• DJSI / S&P CSA Preparation
• CDP (Climate / Water / Forests)

📘 Free resource: Explore The FTSE 2026 Playbook Library — Othello’s ESG disclosure playbook plus focused editions for Thai banks, energy, property, healthcare, technology and more.

Related services from Othello International

Othello International is a Bangkok-based bilingual (EN↔TH) technical translation and ESG advisory firm. Related specialist services:

• ESG ratings submissions — FTSE, MSCI, S&P, SET
• ESG disclosure translation — IFRS S2, GRI, FTSE-ready
• ESG advisory — ratings, climate, materiality