Thailand’s Securities and Exchange Commission is developing a phased roadmap for listed companies to report in line with IFRS S1 and IFRS S2. The approved direction is climate-first, beginning with Scope 1 and Scope 2 greenhouse gas emissions and assurance before expanding to the full sustainability baseline.
As of August 9, 2026, the SEC’s latest English-language announcement says relevant regulations and reporting documents are still being amended. Companies should prepare for the approved direction without treating an earlier consultation timetable as final law.
What the SEC has confirmed
Following public consultation, the Thai SEC confirmed these core principles in November 2025:
- Listed companies will move toward IFRS S1 and IFRS S2 reporting.
- Adoption will be phased, with transition relief.
- The initial phase is climate-first.
- Scope 1 and Scope 2 emissions are an early focus.
- Emissions assurance will use qualified providers and internationally accepted assurance standards.
The SEC also revised how companies will be classified. The SET50 cohort refers to constituents identified in the December 2026 index review, and the SET100 cohort refers to constituents identified in the December 2027 review.
The regulator said final amended rules and related documents would be communicated after completion. Reporting teams should monitor the SEC source directly for the operative dates, reporting periods, covered entities, and transition provisions.
Separate current One Report duties from the ISSB transition
Thai listed companies already report sustainability-related information through Form 56-1 One Report. The ISSB roadmap builds on that environment; it does not mean current reporting can stop until the new amendments are final.
Maintain a requirement register with distinct entries for existing One Report obligations, approved ISSB-roadmap principles, draft or consultation proposals, and voluntary or group reporting. Tag each entry by legal status and last verification date.
This prevents two common errors: describing a proposed start date as settled, or postponing current reporting because a future framework is under development.
Build the climate-first layer now
Start by reconciling the reporting entity to financial consolidation and mapping all facilities, operations, and emission sources. A complete Scope 1 and Scope 2 process should identify:
- Source data and accountable operating owners.
- Unit conversions, methods, estimates, and exclusions.
- Emission-factor source and version.
- Preparer, reviewer, and approval evidence.
- Corrections and changes from the previous reporting period.
For purchased electricity, maintain the distinction between location-based and market-based Scope 2 where the reporting methodology requires it. Review renewable electricity instruments for geography, period, ownership, and retirement.
Although the first phase is climate-focused, IFRS S2 also requires governance, strategy, risk management, and metrics and targets. Map climate risks and opportunities to business plans, financial effects, risk registers, scenario analysis, and board oversight.
Treat assurance as a data-design requirement
The SEC’s direction includes emissions assurance from the early phase. That means a company needs more than a plausible total; it needs a reproducible calculation and evidence that controls operated.
Prepare an evidence index and run a mock walkthrough from a disclosed number back to site-level records. Test access, retention, approvals, estimates, consolidation, and change logs. An ISSA 5000 readiness review can organize this work, while the final engagement must follow the Thai rules and accepted assurance standard that apply.
A no-regret plan while rules are finalised
- Confirm the entity’s current index status and monitor the specified future index reviews.
- Assign an owner to track final SEC amendments and update the requirement register.
- Complete an IFRS S1 and IFRS S2 gap assessment.
- Produce a dry Scope 1 and Scope 2 inventory with evidence and review.
- Establish board, disclosure-committee, and assurance-provider milestones.
- Document transition relief only after final rules confirm that it applies.
This work remains useful if dates or cohort details change because it strengthens the reporting system the confirmed policy direction requires.
Information in this article was verified on August 9, 2026. Thailand’s implementing rules were still under development. This overview is general information, not legal advice.
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