Thailand SEC Introduces Mandatory ISSB Sustainability Reporting Rules Starting 2027

Thailand's Securities and Exchange Commission (SEC) has introduced new sustainability disclosure regulations requiring listed companies to report financial information aligned with the International Sustainability Standards Board (ISSB). Announced on 28 October 2026, the framework will be implemented progressively from the 2027 financial year, beginning with companies included in the Stock Exchange of Thailand's SET50 Index.

The regulations align corporate reporting requirements with IFRS S1, which covers general sustainability-related financial disclosures, and IFRS S2, which addresses climate-related financial information. The SEC issued nine regulatory notifications, which took effect on 26 October 2026, along with updated reporting forms and guidance to help businesses prepare.

 

Phased Implementation Extends Reporting Requirements Through 2031

 

The first phase will apply to companies classified as SET50 constituents during the December 2026 index review. These companies must report sustainability information for the 2027 financial year, with disclosures submitted in 2028. SET100 constituents identified during the December 2027 review will follow, reporting their 2028 information in 2029.

The requirements will subsequently extend to all SET-listed companies, including newly listed businesses, for the 2029 financial year, with reporting in 2030. Companies listed on the Market for Alternative Investment (mai), together with real estate investment trusts, infrastructure funds, infrastructure trusts and property funds, will begin reporting for 2030, with disclosures due in 2031.

 

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Transition Reliefs Provide Flexibility for Companies

 

To support implementation, the SEC has introduced five transition relief measures designed to give companies additional time to develop sustainability reporting capabilities and data systems. These include exemptions from comparative climate-related information during the first reporting year, flexibility in reporting deadlines, permission to use equivalent greenhouse gas calculation standards and temporary relief from disclosing Scope 3 emissions.

The phased approach is intended to reduce the initial compliance burden while enabling companies to strengthen emissions measurement and sustainability reporting processes. By introducing the requirements gradually, the regulator aims to accommodate differences in reporting readiness across larger listed companies, smaller businesses and investment entities.

 

Mandatory Emissions Assurance to Strengthen Disclosure Reliability

 

The SEC will require greenhouse gas emissions information to be verified by assurance providers applying internationally accepted assurance standards. This requirement aims to improve the reliability of emissions data disclosed to investors and the public, supporting more consistent assessments of companies' climate-related performance.

The regulator has also introduced Form 56-1 One Report-S and accompanying disclosure guidance to integrate ISSB-aligned information into corporate reporting. Capacity-building initiatives, including training programs and technical guidance developed with domestic and international partners, will continue to support businesses as they prepare for the new requirements.

 

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Thailand's Adoption Strengthens ISSB-Aligned Reporting in Asian Markets

 

The final rules establish a mandatory reporting framework following earlier consultations and preparations for ISSB adoption. For investors, greater consistency in sustainability disclosures could improve access to comparable information on climate-related financial risks and opportunities across Thai listed companies.

The next stage will focus on companies preparing their reporting systems, emissions inventories and assurance arrangements before their respective implementation dates. Although the regulatory notifications are already in force, mandatory reporting obligations will apply according to the phased schedule, beginning with SET50 companies' 2027 financial information.

 

Source: Securities and Exchange Commission, Thailand