Thailand Adopts International Sustainability Reporting Standards for Listed Companies

Key Takeaways

• New Reporting Requirements: Thailand's SEC has adopted sustainability disclosure rules aligned with IFRS S1 and IFRS S2, beginning with information covering 2027.
• Phased Implementation: SET50 companies will report first in 2028, followed by SET100 companies, the wider SET market, and companies and investment vehicles covered by the final phase.
• Transitional Relief: The regulator has introduced five relief measures, including temporary exemptions from certain reporting requirements and flexibility concerning greenhouse gas emissions calculations.
• Independent Assurance: Greenhouse gas emissions disclosures must be verified by assurance providers using internationally accepted standards.
• Regulations Already Effective: Nine regulatory notifications took effect on October 26, 2026, with mandatory reporting obligations introduced according to the phased schedule.

Deep Dive

Thailand's December review of the SET50 Index will determine which companies must comply first with the country's new sustainability reporting requirements. Those included in the index will be required to disclose information covering 2027 under international standards, with their first reports scheduled for 2028.

The Securities and Exchange Commission announced the rules on October 28, establishing a four-year implementation schedule that will eventually cover the country's listed companies and several types of property and infrastructure investment funds. Nine regulatory notifications underpinning the changes had already taken effect two days earlier.

The rules bring Thailand's corporate disclosures into line with IFRS S1 and IFRS S2, the standards issued by the International Sustainability Standards Board (ISSB). They also require greenhouse gas emissions information to undergo independent assurance, a measure the SEC says is intended to improve the reliability of information available to investors.

The regulator has allowed companies time to prepare, particularly for emissions reporting, where information may need to be collected from outside a company's own operations. Five transitional relief measures will ease some of the initial requirements, including a temporary exemption from reporting Scope 3 emissions.

Under the implementation schedule, companies included in the SET50 following the December 2026 index review will report information for 2027 in 2028. Those included in the SET100 following the December 2027 review will enter the framework a year later, reporting information for 2028 in 2029.

The requirements will extend to all companies listed on the Stock Exchange of Thailand (SET), including initial public offerings, beginning in 2029, with reporting scheduled for 2030.

Companies listed on the Market for Alternative Investment (mai) will follow in 2030, along with real estate investment trusts, infrastructure funds, infrastructure trusts, and property funds. Their first reporting period will be 2030, with disclosures scheduled for 2031.

The schedule places the earliest obligations on companies belonging to Thailand's principal stock indexes. By the time the final group enters the framework, the first SET50 companies will have completed several reporting cycles under the new requirements.

The SEC has revised its reporting forms and registration statements to incorporate the ISSB standards. IFRS S1 establishes requirements for disclosing sustainability-related financial information, while IFRS S2 addresses climate-related risks and opportunities.

Both standards are intended to provide investors with information relevant to assessing a company's financial prospects. Their adoption will require affected Thai companies to prepare disclosures according to a common international framework rather than relying solely on existing reporting practices.

Emissions Reporting and Independent Assurance

The SEC has provided five transitional relief measures to accommodate the work involved in preparing the new disclosures. The measures include an exemption from comparative information in the first reporting year, flexibility over reporting timeframes, permission to use equivalent greenhouse gas emissions calculation standards, and temporary relief from Scope 3 emissions disclosure requirements.

Scope 3 emissions are those associated with activities elsewhere in a company's value chain, rather than emissions produced directly by the company or through its purchased energy. They can include emissions associated with suppliers, transportation, and the use of products sold.

Obtaining this information can be difficult because much of it originates outside the reporting company's operations. The temporary exemption gives affected businesses time to develop the systems and data collection arrangements needed to account for those emissions.

The SEC's announcement does not specify how long the Scope 3 exemption will last or provide the full conditions governing each transitional measure.

Companies will also be required to have their greenhouse gas emissions information verified by assurance providers in accordance with internationally accepted assurance standards.

That requirement brings external verification into the disclosure process. Reported emissions figures will need to be supported by information suitable for assurance, making the quality of underlying records and calculation methods an important part of compliance.

The SEC has not specified the required level of assurance in its announcement. It has, however, made clear that independent verification is part of the new reporting framework rather than a voluntary addition.

The changes also affect the documents through which companies report to the regulator. The SEC has prepared revised reporting forms, including Form 56-1 One Report-S, the annual registration statement and annual report, together with a manual covering preparation of the relevant disclosures.

The nine notifications implementing the changes took effect on October 26. Seven were issued by the Capital Market Supervisory Board and two by the Office of the Securities and Exchange Commission. They address securities registration, corporate financial and operating disclosures, and reporting requirements for investment funds and trusts.

The SEC has been conducting training programs for the private sector since 2024 and said it will continue those efforts as companies prepare for implementation. It has also developed disclosure manuals with domestic and international partners.

The first reporting period begins in 2027, but the wider market will enter the framework gradually over the following three years. For companies included in the final phase, the initial disclosures will not be scheduled until 2031. Those businesses will have additional time to prepare, although the regulations establishing their future obligations are already in force.

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