Under the newly finalized regulations, mandatory sustainability reporting will roll out in a phased implementation timeline beginning in 2028, reflecting performance and data from the 2027 financial year. The largest enterprises listed on the Stock Exchange of Thailand (SET) will lead the transition, with subsequent waves bringing in progressively smaller public companies, alternative exchange listings, and various investment entities through 2031. This structured rollout is designed to establish a unified, highly comparable baseline of environmental, social, and governance (ESG) data for investors, analysts, and international stakeholders.
The regulatory shift addresses long-standing fragmentation within Thailand’s corporate reporting landscape. Since 2022, the SEC has required listed companies to incorporate information regarding ESG performance, corporate governance, human rights, and greenhouse gas (GHG) emissions into their annual disclosures. However, that framework permitted considerable flexibility, allowing firms to choose among a variety of external reporting frameworks—such as the Global Reporting Initiative (GRI) Standards or the recommendations of the Task Force on Climate-related Financial Disclosures (TCFD). While this earlier approach successfully cultivated baseline corporate awareness and reporting habits, it often resulted in inconsistent methodologies and fragmented datasets that proved difficult for global investors to compare directly.
To resolve these challenges and enhance the international competitiveness of Thai capital markets, the SEC launched a formal public consultation in 2024. The initiative explored transitioning the national disclosure regime toward the unified IFRS sustainability reporting standards. This international movement gained significant momentum following the release of the ISSB’s inaugural standards—IFRS S1, governing general sustainability-related disclosures, and IFRS S2, focusing specifically on climate-related disclosures—in June 2023. Global adoption has since accelerated rapidly, with more than 45 jurisdictions worldwide initiating or implementing formal processes to integrate the standards into their domestic regulatory frameworks.
The implementation schedule established by the Thai SEC is structured across four distinct phases to accommodate varying organizational capacities among market participants. Constituents of the SET50 index, representing the fifty largest companies by market capitalization on the Stock Exchange of Thailand, will be the first to adopt ISSB-aligned reporting, with compliance required in 2028 based on 2027 fiscal year data. They will be followed in 2029 by the remaining SET100 companies. By 2030, the requirement will expand to encompass all other companies listed on the primary SET exchange. The final wave, scheduled for 2031, will bring in companies listed on the secondary Market for Alternative Investment (mai), alongside real estate investment trusts (REITs), infrastructure funds (IFFs), infrastructure trusts (IFTs), and provident funds (PFs).
A critical element of the new regulatory framework is the requirement for greenhouse gas emissions disclosures to undergo rigorous external verification. Under the rules, corporate GHG inventories must be audited and verified by accredited assurance providers in accordance with internationally accepted assurance standards, ensuring high data integrity and reliability for investors who rely on these disclosures for capital allocation and risk assessment.
Recognizing the substantial technical and organizational investments required to build robust enterprise-level data collection systems, the SEC has incorporated a comprehensive suite of transition reliefs into the regulation. These provisions are intended to support companies as they develop their internal capabilities and reporting infrastructure. Among these measures are exemptions from providing comparative historical information during the initial year of climate-related reporting, as well as extended flexibility regarding reporting timeframes. Furthermore, companies will be permitted to utilize equivalent GHG emissions calculation standards during the early stages of adoption and will benefit from a temporary exemption from disclosing Scope 3 value chain emissions during the initial implementation period.
By balancing rigorous global alignment with pragmatic transitional support, the Thai regulator aims to elevate the standard of corporate transparency without overwhelming smaller market participants, positioning the country’s financial ecosystem for sustainable long-term growth.
