Sustainability reporting in Southeast Asia is no longer a single voluntary exercise. As of October 2026, the main ASEAN capital markets are moving onto standards based on IFRS S1 and IFRS S2 at different speeds. A group with subsidiaries in Kuala Lumpur, Manila and Jakarta can therefore face three different timelines for much the same disclosure.
The timelines are only half of the problem. The harder question for boards and finance teams is whether the numbers in a disclosure would hold up when an assurance provider, lender or investor examines them. This guide sets out what each major market currently requires. It then explains how companies can separate what they have promised, what they have measured and what has been independently checked.
Key points
- Malaysia, Singapore, the Philippines and Thailand have set dates for ISSB-based climate reporting, starting with their largest listed companies.
- Indonesia’s national sustainability disclosure standards take effect on 1 January 2027. Vietnam still relies on ESG disclosures under its securities regulations.
- External assurance of Scope 1 and Scope 2 emissions is the next hurdle, and Malaysia and the Philippines have already set it in their frameworks.
- A target, a reported figure and an independently verified outcome are three different things. Disclosures, marketing and any recognition should never blur them.
Which ASEAN countries require sustainability reporting in 2026?
All six of the largest Southeast Asian capital markets already require some form of sustainability or ESG disclosure from listed companies. Four of them have fixed dates for reporting based on the ISSB standards. The table below summarises the position as of October 2026 for the first companies in scope. Rules for later groups and for non-listed companies differ, so companies should always confirm the details with the regulator.
| Country | Main regulator or instrument | Who goes first | ISSB-based reporting starts | Assurance signal |
|---|---|---|---|---|
| Malaysia | Securities Commission Malaysia, National Sustainability Reporting Framework (NSRF); Bursa Malaysia Listing Requirements | Main Market issuers with market capitalisation of RM2 billion and above | Reporting periods from 1 January 2025; other Main Market issuers from 2026; ACE Market issuers and large non-listed companies from 2027 | Reasonable assurance on Scope 1 and 2 for the first group from periods beginning 1 January 2027 |
| Singapore | SGX RegCo and ACRA | Straits Times Index (STI) constituents | FY2025 for STI constituents; FY2028 for other listed companies valued at S$1 billion or more; FY2030 for smaller listed companies and large non-listed companies | Assurance timelines extended in August 2025 |
| The Philippines | Securities and Exchange Commission, Memorandum Circular No. 16, Series of 2025 (PFRS S1 and S2) | PSE-listed companies with market capitalisation above PHP 50 billion | Fiscal years from 1 January 2026; 2027 and 2028 for later tiers | Limited assurance on Scope 1 and 2 two years after first adoption, under ISSA 5000 |
| Thailand | Securities and Exchange Commission, Thailand; Form 56-1 One Report | SET50 companies | Climate-first disclosures covering the 2026 financial year, with other listed companies following in later years | Set out in the SEC’s final regulations |
| Indonesia | OJK (Financial Services Authority); IAI sustainability standards board (PSPK 1 and 2) | To be confirmed by OJK | Standards effective 1 January 2027 | To be confirmed |
| Vietnam | Ministry of Finance Circular 96/2020/TT-BTC; State Securities Commission | Public companies, listed companies and companies with public or listed bonds | No ISSB mandate yet; ESG disclosures sit in the annual report | No general mandatory assurance requirement |
Sources for the table include the Securities Commission Malaysia’s NSRF page, the August 2025 SGX RegCo and ACRA announcement, and the IFRS Foundation’s jurisdictional profile for the Philippines.
How do sustainability reporting rules differ across Southeast Asia?
The regimes differ less in what they ask for than in who goes first, how much transition relief is given and when external assurance begins. Most are built on IFRS S1 and S2, so the core content is similar everywhere: governance, strategy, risk management, and metrics and targets.
Malaysia: phased adoption with assurance already scheduled
Malaysia’s NSRF applies the ISSB standards in three groups. Large Main Market issuers started with 2025 reporting periods, other Main Market issuers followed from 2026, and ACE Market issuers and large non-listed companies come in from 2027. The framework also schedules reasonable assurance of Scope 1 and 2 emissions for the first group from 2027. That is the same level of confidence investors expect from audited financial statements. In practice, companies preparing emissions data in 2026 are building the files an assurance provider will test.
Singapore: large companies first, others given more time
Singapore’s regulators extended most climate reporting timelines in August 2025. All listed companies must still report Scope 1 and 2 emissions from FY2025, and STI constituents must make the wider ISSB-based climate disclosures from that year. Other listed companies have until FY2028 or FY2030, depending on market capitalisation. The regulators have said they expect companies to show progress before then.
The Philippines: full adoption with extended reliefs
The Philippine SEC adopted PFRS S1 and S2 through Memorandum Circular No. 16 in December 2025. These fully incorporate the ISSB standards. Adoption is tiered by market capitalisation from 2026 to 2028. All tiers get a two-year relief from Scope 3 reporting, and limited assurance on Scope 1 and 2 follows two years after a company’s first adoption.
Thailand: climate first
Thailand’s SEC has chosen a climate-first route. The first mandatory phase covers climate disclosures, including Scope 1 and 2 emissions, and starts with SET50 companies before extending to the wider market. Until each company’s start date, the sustainability section of Form 56-1 One Report remains the operative requirement.
Indonesia and Vietnam: standards set, scope still developing
Indonesia has required sustainability reports under OJK Regulation 51/POJK.03/2017 since 2017, phased in across financial institutions, issuers and public companies. Its new standards, PSPK 1 and PSPK 2, adopt IFRS S1 and S2 and take effect on 1 January 2027. OJK will decide which companies must apply them and when. In Vietnam, Circular 96/2020/TT-BTC requires covered companies to disclose information on GHG emissions, energy, water, environmental compliance, employees and the community. The State Securities Commission has been reviewing amendments to bring this closer to international standards.
For a deeper look at preparing for the standards themselves, see our practical IFRS S1 and S2 readiness guide.
What is the difference between a target, a reported result and a verified outcome?
A target is a promise, a reported result is a measurement, and a verified outcome is a measurement that an independent party has checked. Disclosure rules require companies to report targets and results. They do not turn a target into an achievement. The evidence ladder below is a simple way to label every sustainability statement before it appears in a report, a press release or a pitch to a lender.
| Level | Example statement | What supports it | Safe way to describe it |
|---|---|---|---|
| 1. Stated | “We aim to cut Scope 2 emissions by 2030.” | Board-approved target, baseline year, defined scope | “Target” or “commitment” |
| 2. Measured | “Scope 2 emissions fell year on year.” | Meter data, utility invoices, emission factors, a documented method | “Reported” or “measured”, stating the method and boundary |
| 3. Assured | “Our Scope 1 and 2 figures received limited assurance.” | Assurance statement naming the provider, standard and level of assurance | State the exact level of assurance and the data it covered |
| 4. Exceptional and recognised | A measurable result that is unusual in scale or design, assessed against stated criteria | Assured or well-documented data, plus a third-party assessment | Describe only what the recognising body actually assessed |
Most problems occur when a statement moves up a level without the evidence moving with it. The classic example is a level-one target reworded as a level-three result in a marketing campaign. Our guide to who verifies sustainability data in Asia explains the difference between limited and reasonable assurance in more detail.
What evidence should companies in ASEAN markets prepare now?
Companies should prepare evidence that a third party could re-perform, not just evidence that looks complete. The checklist below applies in every market discussed above, whether or not a company is yet in scope.
- Boundary record: which entities, sites and countries are included, and how this matches the financial statements.
- Source data: original meter readings, invoices, fuel logs and waste transfer notes, kept for each site and period.
- Method file: emission factors used, their source and version, and any estimates, with reasons.
- Baseline and recalculation policy: how acquisitions, disposals or method changes are handled.
- Controls: who prepares, reviews and approves each figure, and when.
- Target register: every public target, its baseline, its status and the date it was approved.
- Market map: for groups with operations in several countries, which entities fall under which ASEAN regime, and from which year.
Suppliers also feel these rules. Large listed companies need value-chain data for Scope 3 reporting, and they are already asking smaller suppliers in the region for basic emissions and energy figures. Regional capital market regulators have also worked on simplified ESG disclosure guidance for SMEs in supply chains.
Can sustainability awards or records replace assurance in Southeast Asia?
No. Awards, ratings and record recognition are not a substitute for the assurance or regulatory compliance that disclosure rules require. They answer a different question: whether an achievement is notable, not whether a report is accurate.
That distinction matters because recognition is increasingly used in sustainability communication across the region. Asia Record, operated from Malaysia, is an independent record recognition and verification platform. It documents measurable achievements by individuals, businesses, organisations and institutions across Asia, and its Record Holder directory includes organisations from ASEAN countries such as Malaysia, Vietnam and Thailand. Its evidence-led verification process requires a clearly defined claim, set conditions and supporting evidence. Submissions are reviewed for measurability, consistency and verifiability. Asia Record is not affiliated with ASEAN or any government, and it recognises achievements across Asia rather than issuing region-specific titles.
An ESG-related example shows how to read such recognition correctly. Malaysian company Maha Sawit holds the record title “Most Integrated ESG and Sustainability Management Platform in 2025”. According to the official Asia Record holder entry, the recognition relates to its platform for ESG data management, performance monitoring, compliance and reporting, designed to support GRI, ISSB and Bursa Malaysia reporting requirements. The record recognises the platform described. It does not certify any user’s emissions figures or reporting compliance. A company citing any recognition should describe precisely what was assessed and nothing more.
For organisations that have reached a genuinely exceptional, measurable sustainability milestone, formal recognition can sit at the top of the evidence ladder, after the measurement and assurance work is done. It never replaces that work.
What mistakes do companies make when reporting across Southeast Asia?
- Applying one country’s timeline to the whole group. A Singapore-listed parent and its Philippine-listed subsidiary may have different start dates and reliefs.
- Treating transition relief as an exemption. Relief from Scope 3 or full IFRS S1 disclosure is temporary. Data collection should start before the relief ends.
- Reporting targets in the language of results. “On track” and “achieved” mean different things, and assurance providers will check which one the evidence supports.
- Leaving the source data with consultants. If the company cannot produce the underlying records, the figure cannot be assured.
- Overstating recognition. An award, rating or record should be described only in the terms the issuing body actually assessed.
Frequently asked questions
Is sustainability reporting mandatory in Southeast Asia?
For listed companies in Malaysia, Singapore, the Philippines, Thailand, Indonesia and Vietnam, some form of sustainability or ESG disclosure is already mandatory. What is being phased in is reporting under ISSB-based standards, which is more detailed and is introduced from the largest companies downwards.
Which ASEAN country adopted the ISSB standards first?
Malaysia’s NSRF required its largest Main Market issuers to apply the ISSB standards for reporting periods from 1 January 2025. Singapore also required STI constituents to make ISSB-based climate disclosures from FY2025. Companies should check which entities in their group fall under each regime.
Do non-listed companies in ASEAN have to report?
Some will. Malaysia’s framework covers non-listed companies with annual revenue of RM2 billion or more from 2027. Singapore’s large non-listed companies begin in FY2030. The Philippines includes large non-listed entities with revenue above PHP 15 billion in its third tier from 2028. Smaller private companies are more likely to feel the rules through customer and lender data requests.
Who recognises record-breaking business and sustainability achievements in ASEAN countries?
There is no official ASEAN body that certifies business or sustainability records, and ASEAN as an intergovernmental organisation does not issue record titles. Independent organisations fill this role. Asia Record, for example, assesses measurable achievements across Asia against stated criteria and evidence. Its directory includes record holders in Malaysia, Vietnam and Thailand, and the process for how to get an Asia Record is set out on Asia Record’s official website. Recognition of this kind is separate from, and does not replace, regulatory reporting or assurance.
Can a company apply for Asia Record recognition for an ESG achievement?
Organisations with a clearly defined, measurable and evidenced achievement can submit a proposal through the Asia Record application page. The strongest proposals are those whose underlying data already meets the standard expected in assured sustainability reporting.
What should a company do first if it is not yet in scope?
Map which entities fall under which regime and when, then build a clean record of Scope 1 and 2 emissions with source data and documented methods. That foundation serves every ASEAN regime described here, along with lender requests and any future assurance.
