Since 2026, sustainability information has ceased to be merely a disclosure matter for many Taiwan-based Japanese corporate groups. It has instead become a broader management issue that simultaneously affects group reporting timelines, carbon emissions data governance, third-party assurance and external assurance arrangements, and readiness for carbon pricing regimes. In particular, when a Tokyo headquarters has already begun preparing disclosures under the SSBJ Standards—and may even have established its reporting process early through voluntary application—the question of whether a Taiwan subsidiary can directly rely on the headquarters’ version, and whether it can still align that version with local regulatory requirements in time, has become one of the most common practical challenges facing CFOs and ESG leaders.
This issue has gained momentum over the past year not only because sustainability disclosure regimes in both Taiwan and Japan are moving into implementation, but also because both jurisdictions have now entered the era of carbon pricing, albeit through different policy instruments and at different speeds. In Taiwan, the carbon fee has formally taken effect, and an emissions trading system (ETS) has also moved into the pilot-planning stage. In Japan, by contrast, the Global Warming Countermeasures Tax has already long been in place, while emissions trading and related carbon pricing measures continue to advance under the broader policy framework of GX (Green Transformation).
GX can be understood, in simple terms, as Japan’s overarching policy framework for addressing two challenges at once: ensuring stable energy supply and achieving its 2050 net-zero target. It combines fiscal investment, industrial transition support, financial instruments, and carbon pricing mechanisms into a single integrated strategy. Its defining feature is not an exclusive reliance on high charges or punitive measures, but rather a phased approach that first supports corporate transition through investment incentives and institutional design, and then gradually strengthens decarbonization discipline through emissions trading, carbon pricing mechanisms, and clearer price signals.
Against this backdrop, the real issue now facing Taiwan-based Japanese companies is no longer simply whether sustainability disclosures must be made. The more pressing question is whether one and the same set of emissions data can simultaneously support disclosure obligations in both Taiwan and Japan, third-party assurance, and the requirements of carbon pricing mechanisms such as Taiwan’s carbon fee and ETS. If companies continue to respond on the assumption that the Japanese headquarters prepares first and the Taiwan subsidiary merely adjusts afterward, the most likely outcome in practice will not be a mere formatting gap, but duplicated data preparation in both Tokyo and Taipei—potentially requiring supporting working papers, verification steps, and filing processes to be reorganized from the ground up.
1. Why Taiwan and Japan’s Applicability Thresholds and Disclosure Timelines Cannot Be Directly Aligned
The two jurisdictions also apply different underlying logic when determining which entities fall within the scope of sustainability disclosure requirements. Japan uses the average market capitalization over the past five years as its benchmark, whereas Taiwan relies on paid-in capital as of the end of the reporting year. The former is market-based, while the latter is based on statutory capital. As a result, even where a group’s overall scale appears comparable, the parent company and its subsidiary may not enter the disclosure regime in the same year.
For cross-border groups, this difference creates at least three practical consequences:
- Entity becomes subject to regulation first does not necessarily follow the headquarters’ timeline.
- Even when both are described as “FY2026 data,” the actual reporting period and filing deadline may differ.
- Even if the headquarters has already completed a disclosure draft, the Taiwan subsidiary may still need to separately adjust data boundaries, fiscal cut-off points, and filing formats.
| Taiwan–Japan Comparison Table of Sustainability Disclosure Thresholds and Disclosure Timelines__Prepared by S | ||
| Item | Japan SSBJ | Taiwan FSC |
| Indicator | Market capitalization | Paid-in capital (par value basis) |
| Reference Date | 5year average market capitalization, calculated by looking back from the fiscal year-end immediately preceding the applicable year | Paid-in capital as of December 31, the year-end date of the reporting year |
| Applicable Fiscal Year | March year-end (4/1–3/31) | December year-end (1/1–12/31) |
| Phase 1 | ≥JPY 3 trillion (approx. 69 companies) | ≥TWD 10 billion or more (approx. 126 companies) |
| Reporting Year | FY2026 | FY2026 (ROC Year 115) |
| FIRST Disclosure / Filing Timing | June 2027 | By March 16, 2027 |
| Filing of the annual securities report after the shareholders' meeting | Disclosed together with the annual report | |
| Phase 2 | ≥JPY 1 trillion or more (approx. 200+ companies) | ≥TWD 5 billion (approx. 118 companies) |
| Reporting Year | FY2027 | FY2027 (ROC Year 116) |
| Disclosure / Filing Timing | June 2028 | By March 16, 2028 |
| Phase 3 | ≥JPY 500 billion | Less than TWD 5 billion (all remaining listed and OTC companies, approx. 1,694 companies) |
| Reporting Year | FY2028 | FY2028 (ROC Year 117) |
| Disclosure / Filing Timing | June 2029 | By March 16, 2029 |
| ※ Timing note: For Phase 1, the first external disclosure in both Taiwan and Japan falls in 2027; the principal difference lies in the applicable fiscal year. | ||
| ※ At present, the mandatory application roadmap developed by Japan’s Financial Services Agency (FSA) and the SSBJ is intended to apply to companies listed on the Prime Market. | ||
| ※ The mandatory application timeline for Phase 4 under Japan’s SSBJ regime, namely the remaining companies listed on the Prime Market, has not yet been formally announced at this stage. | ||
As the table shows, Japan’s SSBJ framework uses the average market capitalization at the end of the past five fiscal years as the basis for determining applicability, whereas Taiwan uses paid-in capital as of the end of the reporting year. In other words, even where a group’s overall scale appears similar, the parent company and its subsidiary may not fall within the scope of mandatory disclosure in the same year. Which entity becomes subject to regulation first, and which one enters the actual preparation cycle first, does not necessarily follow the headquarters’ timeline.
More importantly, even if the first phase in both Taiwan and Japan can be understood as beginning with FY2026 data, that does not mean the two sides can directly share the same set of disclosure content. Many Japanese companies operate on a March fiscal year basis, whereas Taiwan generally follows a December year-end. Combined with differences in disclosure timing, filing formats, and internal review cycles, this means that even where a company seeks to use the Japanese headquarters’ version as the filing working papers for its Taiwan submission, data segmentation, timing adjustments, and format restructuring are often still required.
2. What Does Early Action by the Japanese Headquarters Mean for Taiwan Subsidiaries?
This means that some large Japanese corporate groups may already have begun establishing internal data definitions, emissions boundaries, disclosure workflows, working paper structures, and assurance response protocols even before mandatory application begins. Once the headquarters has completed these preparations, it becomes almost inevitable that overseas subsidiaries will be asked to provide data on a consistent basis and in a consistent format. Even where a Taiwan subsidiary has not yet entered the same disclosure timetable, it may still be required—at the group governance level—to prepare and respond on an accelerated basis.
Accordingly, for Taiwan-based Japanese companies, the real challenge has never been limited to the question of when a regulation formally takes effect. Rather, it lies in when the headquarters begins requesting data, how far those requests extend, and whether the Taiwan side is prepared to deliver information in a verifiable form. This is also why, during the same post-2026 transition period, some companies primarily experience regulatory compliance pressure, while others are dealing more directly with pressures arising from group governance and information integration.
3. Why Disclosure Will No Longer Be Just Disclosure After 2026
In Taiwan, the sustainability-related financial information chapter must be submitted to and approved by the board of directors, and its reporting entity, reporting period, information quality, and the data and assumptions used must remain consistent with the financial statements. In particular, Scope 1 and Scope 2 greenhouse gas emissions information must, in accordance with applicable requirements, be disclosed together with an independent third-party assurance opinion. In Japan, the Financial Services Agency’s official roadmap also contemplates the introduction of mandatory assurance one year after the mandatory application of the SSBJ Standards, indicating that sustainability information will gradually be brought within a more clearly defined external assurance framework.
4. Emissions Data Will Become a Cross-Regime Foundation
In other words, the same emissions data may increasingly be used for multiple purposes: sustainability-related disclosures, third-party assurance, carbon fee calculations, voluntary emissions-reduction plans, and the future design of allowance allocation, compliance, or trading arrangements under an ETS.
This means that the capability companies need to build is not merely the ability to produce data that can be disclosed. They will need data governance capabilities that support verifiability, cross-regime usability, and alignment with financial reporting timelines.
5. Four Priorities for Taiwan-Based Japanese Companies
- Take Stock of the Emissions Data Foundation：Companies should confirm whether the data sources, calculation methodologies, organizational boundaries, and supporting documentation for Scope 1 and Scope 2 emissions are consistent. This helps prevent individual departments from maintaining separate records based on inconsistent definitions or methodologies.
- Develop a Taiwan-Japan Reporting Timeline Matrix：The fiscal years, disclosure milestones, board review dates, assurance work periods, and filing deadlines of the Japanese headquarters and Taiwan subsidiary should be mapped and compared in full. This reduces the risk of discovering only at the final stage that the respective reporting cycles cannot be aligned.
- Integrate Sustainability Information into Financial-Reporting-Grade Processes：Sustainability information can no longer depend solely on a single department compiling information shortly before filing. Companies should progressively establish recurring cross-functional processes for data collection, review, audit trail retention, and approval, using financial reporting as the operational benchmark.
- Plan for External Professional Support Early：During the sustainability disclosure preparation period, companies should look beyond whether their existing financial statement audit framework can simply be extended. They should seek early support from professionals with experience in sustainability disclosures, third-party assurance, and cross-border coordination between Taiwan and Japan.
For Taiwan-based Japanese companies, differences between the Taiwanese and Japanese sustainability disclosure regimes are not merely a matter of mismatched filing timelines. They represent a broader challenge involving group-level data governance, internal coordination, and external assurance arrangements.
What companies need to prepare in advance is not simply the disclosure documentation itself. More fundamentally, they need to establish a data-management framework that is verifiable, usable across multiple regulatory regimes, and capable of responding to both Japanese headquarters’ requirements and Taiwan’s regulatory expectations. As voluntary application, carbon fee regimes, and ETS mechanisms continue to develop, companies that align regulatory requirements, integrate processes, and plan for professional support early will be better positioned to avoid higher rework costs in future reporting, assurance, and cross-regime implementation.