The Data Foundation an SSBJ Filer Needs Before FY2027

Japan’s first mandatory sustainability disclosures are filed inside the annual securities report, and that report is due within three months of the fiscal year end. For a company closing its books on 31 March 2027, the filing lands in June 2027. The information in it has to be collected across the whole fiscal year that began in April 2026.

That is the part teams underestimate. The deadline is a reporting deadline. The work is a collection problem, and collection cannot be done retroactively for a year that has already been lived.

What is already fixed

The SSBJ issued three standards on 5 March 2025: the Universal Standard on application, Theme Standard No. 1 on general disclosures, and Theme Standard No. 2 on climate. All three were revised on 13 March 2026 (SSBJ).

The obligation itself comes from securities law rather than from the standards. Cabinet Office Ordinance No. 5 of 2026 was promulgated and took effect on 20 February 2026. Prime-listed companies with an average market capitalisation of ¥3 trillion or more disclose under SSBJ for fiscal years ending on or after 31 March 2027. Companies at ¥1 trillion and above follow from fiscal years ending on or after 31 March 2028 (Deloitte Japan). A third tier at ¥500 billion is set out for 2029 in the FSA’s roadmap, and the sequence is laid out in our SSBJ roadmap.

So the first cohort has one fiscal year of collection left, and that year is running now.

The report is a view. The dataset is the thing.

Most SSBJ readiness work starts from the document: which disclosures are required, what the sections will say, who drafts them. That work is real, and it is second. What an assurance provider tests is not the prose. It is whether a number in the filing can be traced back to something that existed before the filing was written.

Four properties of the underlying dataset decide that. None of them are software questions.

An entity master that reconciles to the consolidation

IFRS S1 paragraph 20 requires sustainability disclosures to cover the same reporting entity as the related financial statements (IFRS S1), and the SSBJ Universal Standard carries the same requirement into Japanese practice.

Ask a sustainability team for its reporting scope and you usually get a list of sites. Ask the consolidation team and you get a list of legal entities. These are different objects, and only the second one reconciles to anything an auditor holds.

An entity master is that second list, maintained as data. For each legal entity: its consolidation treatment, its country, its own fiscal year end, its functional currency, and one named person who owns its numbers. Overseas subsidiaries with a December year end are the row that breaks first, because their data has to be aligned to the parent’s period before it can be added to anything.

Where the two lists diverge, the finance list wins. We have written separately on where the boundaries actually pull apart, and it is worth settling before any collection template goes out.

Boundary rules written down once, per scope

IFRS S2 paragraph 29(a) requires emissions to be measured in accordance with the Greenhouse Gas Protocol Corporate Standard (2004) unless a jurisdictional authority or an exchange requires otherwise, and it requires Scope 1, Scope 2 and Scope 3 to be disclosed separately. It also requires location-based Scope 2 emissions plus information about the contractual instruments a reader needs to understand them, and disclosure of the measurement approach, inputs and assumptions used (IFRS S2).

Read as a data requirement rather than a disclosure requirement, that paragraph says something narrow. Every entity in the master needs a recorded answer to three questions. Does its energy use enter Scope 1 and 2, or does it belong in Scope 3? Which contractual instruments apply to its purchased electricity? What method was used, and what were the assumptions?

Write the rule once, apply it across the master, and record the exceptions as exceptions. Teams that instead decide entity by entity, inside a spreadsheet, produce a number nobody can reproduce a year later, including themselves.

Emission factors carry a version and a date

An emission factor is not a constant. In Japan it is a published, dated, utility-specific value that changes every year.

The Ministry of the Environment publishes basic and adjusted emission factors for each electricity retailer under the calculation, reporting and disclosure system established by the Act on Promotion of Global Warming Countermeasures. The set for fiscal 2024 was published on 9 January 2026 (Ministry of the Environment). The SSBJ has also issued implementation guidance, dated 11 June 2026, on disclosing under the climate standard when emissions have been measured by the method that system prescribes (SSBJ).

The operational consequence is that a factor stored as a bare number is not usable evidence. Each factor needs its source, its vintage year, its publication date, and the period over which it was applied. When a factor set is revised mid-preparation, that record is what tells you which rows have to be recalculated and which do not.

The same applies to any factor library bought from a vendor or lifted from an industry database. If you cannot say where a factor came from and which version it was, you cannot defend the number built on top of it.

Evidence that survives someone else asking

Assurance follows disclosure by one year. For the first tier that means fiscal years ending on or after 31 March 2028, at limited assurance, and we have set out the expected sequence and scope separately.

The practical test is simple to state and uncomfortable to pass. Pick any figure in the draft filing. Can you produce, in a few minutes, the source document behind it, the person who entered it, the person who reviewed it, the date of each step, and any change made after the first entry?

An evidence trail is that record, created at the moment of collection. Reconstructed afterwards, it is neither evidence nor a trail. This is the reason the annual questionnaire model fails under assurance even when its arithmetic is correct. A spreadsheet returned by email in May contains a number and nothing else.

What the transitional relief buys, and what it does not

The ordinance carries genuine relief for the first two years of application. Companies may use two-stage disclosure, omitting the SSBJ information from the annual report and filing it through an amended report by the following half-year report deadline. The disclosure guidelines extend safe-harbour treatment to Scope 3 figures, so a disclosure made on a reasonable basis and described specifically does not attract misstatement liability (Deloitte Japan). The Universal Standard also permits comparative information to be omitted in the first year of application.

Every one of these moves a document deadline. None of them moves the collection year. The data for the fiscal year ending March 2027 is generated during that fiscal year, whether or not the disclosure about it arrives in June or later.

Where to start

Get the consolidation schedule and turn it into a table. One row per legal entity, with treatment, country, fiscal year end and a named owner. Send nothing out until this exists.

Decide the scope rule centrally and publish it. One page, applied to the whole master, with exceptions listed by entity and reason.

Version your factor library. Source, vintage, publication date, applied period. Retire the untraceable factors now rather than in the assurance walkthrough.

Change the collection cadence to match the financial close. Quarterly collection alongside the financial close produces four sets of contemporaneous evidence in a year. One annual survey produces none.

Test one number end to end. Choose a single Scope 2 figure from a mid-sized overseas subsidiary and walk it from the filing back to the invoice. Whatever breaks in that walk is the actual state of the foundation.

Everything else in an SSBJ programme sits on these. Standards can be read in an afternoon. A dataset with an entity master, a written rule, versioned factors and contemporaneous evidence takes a fiscal year to produce, and there is one of those left.

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Check where you stand. The free SSBJ readiness check takes about three minutes and scores the dimensions an assurance provider will actually test: socious.io/ssbj-check.

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