Japan sustainability reporting rules: SSBJ timetable and who must report

Japan's mandatory sustainability reporting timetable begins with Prime Market companies whose average market capitalisation is at least ¥3 trillion. Their first Sustainability Standards Board of Japan (SSBJ) reports cover financial years ending in March 2027. The threshold is based on an average of the previous five fiscal year-ends, so one unusually high or low valuation does not decide the reporting cohort.

That calculation is the first practical step for reporting teams. A company can be familiar with the SSBJ standards and already publish a sustainability section without yet being required to state compliance with them. Listing market, average market capitalisation and financial year-end determine when the mandatory duty begins.

The timetable then moves through two further cohorts. Companies between ¥1 trillion and ¥3 trillion follow a year later, and those between ¥500 billion and ¥1 trillion follow in the year ending March 2029. Japan has not yet fixed the mandatory start date for the remaining Prime Market companies.

Who must report and when

The Financial Services Agency (FSA) roadmap phases SSBJ reporting across companies listed on the Tokyo Stock Exchange (TSE) Prime Market. The market-capitalisation test uses the average value at the end of the five fiscal years up to the company's most recent year-end. A company listed for fewer than five years uses the years available.

The roadmap is expressed around March year-ends because that is the common Japanese reporting calendar. Companies with a different year-end need to match the rules to their own financial period rather than treating March as a universal filing date.

The five-year average can also place a company in a different cohort from the one suggested by its current share price. Reporting teams should keep the calculation, the underlying year-end values and the listing status with their scope assessment. A later reviewer should be able to see why the company selected its first mandatory year.

Existing sustainability disclosure is not SSBJ compliance

Listed companies in Japan have included a sustainability section in their annual securities reports since financial years ending March 2023. Those disclosures use the familiar governance, strategy, risk management, and metrics and targets structure associated with the Task Force on Climate-related Financial Disclosures.

The SSBJ requirement goes further. An in-scope company must apply the designated Japanese sustainability disclosure standards and state that it has complied with them. It must also identify any transition relief used. A company publishing climate or sustainability information under the earlier securities-report rule should not assume that the same material automatically satisfies the SSBJ standards.

This distinction also affects international comparisons. Japan has adopted standards built from the International Sustainability Standards Board (ISSB) baseline, but the local timetable, filing location and reliefs come from Japanese securities rules. The ISSB, IFRS S1 and IFRS S2 guide explains the baseline; the Japanese rules decide who must use it and when.

What the SSBJ standards cover

SSBJ issued its first standards in March 2025 and revised them in March 2026. The package has three parts:

• Application of the Sustainability Disclosure Standards, which sets the general basis for using the standards;
• General Disclosures, covering material sustainability-related risks and opportunities; and
• Climate-related Disclosures, covering climate-specific governance, strategy, risk management, metrics and targets.

The standards are designed to be functionally aligned with International Financial Reporting Standard S1 (IFRS S1) and International Financial Reporting Standard S2 (IFRS S2) while operating within Japan's reporting system. SSBJ has included Japanese options and transitional provisions where local implementation requires them. A statement that a report is “ISSB aligned” therefore does not replace the need to check the designated SSBJ text.

SSBJ information sits inside the annual securities report

The mandatory disclosures belong in the annual securities report rather than a separate sustainability publication. This places sustainability-related financial information alongside the company's financial statements, risk disclosures and governance information. A standalone sustainability report can still provide additional detail, but it does not displace the statutory filing.

For the first mandatory year and the following year, Japan allows a two-step disclosure route. A company can file its annual securities report without the complete SSBJ information, then add the sustainability disclosures through an amended report by the deadline for its next half-year report.

The relief gives companies more time after the financial statements are completed. It does not remove the reporting obligation or turn the missing information into an optional supplement. Investors receive the financial and sustainability information at different points, so the company should explain the timing clearly and ensure that the amended filing can be reconciled with the original report.

Scope 3 and forecasts require a visible evidence trail

The FSA rules recognise that Scope 3 emissions and forward-looking information rely on estimates, assumptions and information outside a company's direct control. Companies using that information must explain the reasoning process and the internal procedures used to prepare the disclosure.

That requirement changes the work behind the number. A Scope 3 total needs more than an emissions factor and a spreadsheet output. Reporting teams should retain the boundary decision, supplier or activity data, estimation hierarchy, factor source, calculation version and review record. Forecasts and scenario analysis need the same treatment for assumptions and approvals.

These records are likely to span finance, sustainability, procurement, risk and operating teams. The sustainability reporting controls guide sets out how named ownership and retained evidence can connect those systems before the filing is assembled.

Assurance begins one year after mandatory reporting

The FSA roadmap places assurance one year behind each reporting cohort. For the first two assurance years, the required work is limited to specified information rather than the entire SSBJ report. The scope is expected to expand after that initial period.

Assurance providers will have to be registered, and the proposed system is not restricted to one profession. Detailed provider requirements and the later assurance scope remain implementation points to monitor.

A one-year delay does not justify postponing evidence work. The first mandatory filing becomes the comparative and process baseline for the assured report that follows. Weak ownership or undocumented estimates in year one are harder to repair after the reporting cycle has closed.

What reporting teams should settle first

1. Calculate the cohort. Record the last five fiscal year-end market capitalisations, the average and the company's Prime Market status.
2. Confirm the first reporting period. Match the cohort to the company's actual year-end and annual securities report timetable.
3. Map the SSBJ requirements. Separate the mandatory standards from existing voluntary reports and earlier securities-report disclosures.
4. Decide whether to use two-step disclosure. Plan the original and amended filings as one controlled reporting process.
5. Document estimates and forward-looking information. Retain methods, source data, assumptions, review and approval.
6. Prepare for assurance. Identify the first assured year and build traceable evidence during the first mandatory cycle.

The date for smaller Prime Market companies remains open. Those businesses can still use the current standards and cohort rules to map data and controls, but they should not present an unannounced mandatory date as settled.

For companies already inside the timetable, the scope calculation comes before the disclosure checklist. Five year-end values determine the cohort; the cohort determines the first report; and the annual securities report determines where the information becomes a legal filing.

Sources

• Japan FSA: roadmap for sustainability disclosure and assurance
• Japan FSA: final ordinance and public-consultation results
• SSBJ: inaugural sustainability disclosure standards
• SSBJ: revised sustainability disclosure standards, March 2026
• IFRS Foundation: Japan jurisdictional profile
• Feature image: Tokyo Stock Exchange main building by Kakidai, CC BY-SA 4.0