ESRS and ISSB Standards Alignment: A 2026 Preparer's Guide

If your company has EU-regulated entities and operations in jurisdictions adopting ISSB Standards, you are already a dual-framework preparer, whether you planned to be or not. As EY confirms, "a multi-national entity may need to comply with both sets of standards if it has reporting entities in jurisdictions that require compliance with ESRS, and reporting entities in jurisdictions that require compliance with ISSB Standards." This guide tells you exactly what that means in practice: where the frameworks converge, where they diverge, and how to build one data collection process that satisfies both without running parallel workstreams.

Key takeaway: ESRS and ISSB Standards are broadly aligned on climate disclosures, but they are not equivalent. The joint EFRAG-ISSB Interoperability Guidance published on 2 May 2024 is the authoritative reference for dual-framework preparers, and it explicitly states: "This document is not a formal statement of equivalence."

What Is the Difference Between ISSB and ESRS?

The two frameworks share a common architecture but diverge fundamentally on materiality, scope, and assurance. Both use the TCFD four-pillar structure (governance, strategy, risk management, metrics and targets). Both define financial materiality the same way: information that would influence investor decisions. That alignment is real and useful.

The differences, however, are structural:

The materiality gap is the central operational challenge. ESRS requires a double materiality assessment covering both what affects enterprise value (financial materiality) and what the company's activities mean for people and the environment (impact materiality). ISSB requires only the former. This is not a minor technical difference: it changes which topics you must report on, how you scope your value chain analysis, and how you document your assessment.

What Are the 4 Pillars of ISSB?

IFRS S1 and IFRS S2 both require disclosures structured around four content pillars, inherited from the TCFD framework and applied consistently across all sustainability topics:

1. Governance, how the board and management oversee sustainability-related risks and opportunities
2. Strategy, how identified risks and opportunities affect the business model, strategy, and financial planning
3. Risk management, the processes used to identify, assess, prioritise, and monitor sustainability risks
4. Metrics and targets, the quantitative and qualitative measures used to track performance

ESRS uses the same four-pillar structure, which is one of the foundations of interoperability. A disclosure prepared under ESRS E1 Governance requirements will, in most cases, satisfy the equivalent IFRS S2 Governance requirement. The tabular mapping in Section 2 of the Interoperability Guidance shows this paragraph by paragraph.

How Aligned Are IFRS S2 and ESRS E1 on Climate?

Almost all climate-related disclosures required by IFRS S2 are included in ESRS E1. This is the headline finding of the Interoperability Guidance, and it is the strongest basis for building an integrated process. An entity starting with ESRS E1 will, in most cases, have satisfied the substance of IFRS S2.

The catch is directional. Section 4.2 of the Interoperability Guidance lists ESRS E1 disclosures that have no equivalent in IFRS S1 or IFRS S2. These are the incremental ESRS-only requirements that an entity starting with ISSB Standards must add to achieve ESRS compliance. They include specific datapoints on transition plan milestones, energy mix disclosures, and certain physical risk metrics that go beyond what IFRS S2 requires.

KPMG summarises the practical significance well: "Although the guide represented a point-in-time analysis of identified differences and did not include all areas of the standards, it gave companies confidence that the ISSB and EFRAG had agreed on common areas of their climate-related disclosures and highlighted significant alignment." (KPMG, March 2025)

Two specific areas where the frameworks diverge on climate are worth flagging:

• Scope 3 emissions: Both frameworks require Scope 3 disclosure, but ESRS E1 specifies additional contextual requirements around value chain data quality and estimation uncertainty that go beyond IFRS S2's measurement framework.
• Scenario analysis: Both require climate resilience assessment using scenarios, but ESRS E1 is more prescriptive about the scenarios to consider and the disclosure of assumptions. Preparers using ISSB transition relief on scenario analysis in year one should check whether that relief is compatible with ESRS E1 requirements for the same period.

Does Your ESRS Double Materiality Assessment Count for IFRS S1?

Yes, to a large extent, and the ISSB said so explicitly in November 2024. This is the most underutilised piece of guidance in the dual-framework space.

The ISSB's November 2024 materiality guidance clarified that a company's ESRS double materiality assessment can serve as the starting point for identifying sustainability matters under IFRS S1, because the financial materiality component of the ESRS assessment aligns with ISSB's materiality concept. As KPMG notes: "[The guidance] makes it clear that a company's dual reporting can, to a large extent, make use of its ESRS double materiality assessment to identify sustainability matters under the IFRS Sustainability Disclosure Standards." (KPMG, March 2025)

The practical implication: do not run a separate ISSB materiality assessment from scratch. Instead:

1. Complete the ESRS double materiality assessment in full (both financial and impact dimensions).
2. Extract the financial materiality findings. These map directly to IFRS S1's materiality concept.
3. Document the mapping explicitly so auditors and reviewers can trace the ISSB materiality conclusion back to the ESRS assessment.
4. Check whether any topics are financially material under IFRS S1 that did not surface in the ESRS assessment. This is unlikely but possible, particularly for topics outside the ESRS prescribed set (E1-E5, S1-S4, G1).

The one area where the ESRS assessment cannot substitute for ISSB analysis is impact-only materiality: topics that are material under ESRS because of their impact on people or the environment, but that have no financial materiality for the company. Under IFRS S1, these topics do not require disclosure. Preparers must be clear in their documentation about which disclosures are driven by financial materiality (required under both frameworks) and which are driven by impact materiality (ESRS-only).

For a deeper treatment of the materiality distinction, see Finrep's analysis of whether double materiality is required under IFRS sustainability standards.

Which International Standards Are ESRS Designed to Align With?

ESRS was explicitly designed to achieve a high degree of alignment with ISSB Standards, with a specific focus on climate. The IFRS Foundation, European Commission services, and EFRAG worked together during the development of both sets of standards to maximise interoperability. ESRS also incorporates alignment with GRI Standards for the impact materiality dimension, though GRI is not part of the ISSB framework.

The Interoperability Guidance covers:

• IFRS S1 (general requirements) vs. ESRS 1 and ESRS 2
• IFRS S2 (climate) vs. ESRS E1

It does not cover ESRS E2 (pollution), E3 (water and marine resources), E4 (biodiversity), E5 (circular economy), S1-S4 (social topics), or G1 (business conduct). For these topics, preparers must independently assess whether IFRS S1's general requirements demand equivalent disclosures.

Handling Non-Climate Topics: ESRS E2-E5, S1-S4, and G1

This is the gap that the Interoperability Guidance does not fill, and where most dual-framework preparers are flying blind.

ESRS covers five environmental standards, four social standards, and one governance standard beyond climate. ISSB Standards currently cover only climate (IFRS S2) plus the general requirements in IFRS S1. For every non-climate topic, the question is: does IFRS S1 require equivalent disclosure?

The answer depends on financial materiality. IFRS S1 requires disclosure of all sustainability-related risks and opportunities that are material to investors, regardless of topic. So:

• If water risk is financially material to your business (e.g., a beverage manufacturer in a water-stressed region), IFRS S1 requires disclosure of that risk even though there is no IFRS standard equivalent to ESRS E3. The ESRS E3 disclosures you prepare will largely satisfy IFRS S1's general requirements for that topic, but you must apply IFRS S1's framework (governance, strategy, risk management, metrics) rather than assuming ESRS E3 format is sufficient.
• If a social topic (e.g., own workforce under ESRS S1) is not financially material under IFRS S1's definition, you are not required to disclose it under ISSB Standards, even if ESRS requires it due to impact materiality.
• Conversely, if a topic is financially material under IFRS S1 but falls outside the ESRS prescribed set, ESRS may not require disclosure of it at all (subject to the ESRS materiality assessment).

For industry-specific disclosures, the picture is further complicated by the EC's decision not to develop sector-specific ESRS. As PwC noted in its November 2025 comment letter to the ISSB: "In the absence of an IFRS Sustainability Disclosure Standard, we recommend that the ISSB leverage ESRS metrics to develop industry-specific metrics." (PwC, November 2025) Until that work is done, SASB Standards remain the primary source of industry-specific guidance under IFRS S1.

Transition Relief: What You Cannot Simply Combine

The Interoperability Guidance explicitly flags that transition relief provisions differ between the two frameworks, and does not resolve the conflict. Preparers who assume they can apply both sets of transition reliefs simultaneously risk non-compliance with one or both frameworks.

Key differences to assess:

• Comparative information: ISSB Standards permit omission of comparative sustainability information in the first year of reporting. ESRS has different transition provisions for comparative data. Check whether applying the ISSB first-year relief creates a gap in your ESRS disclosures.
• Scope 3 emissions: ISSB Standards permit a one-year delay in Scope 3 disclosure in the first year. ESRS E1 has its own phasing for Scope 3 that may not align with the ISSB timeline. If your ESRS first reporting year and your ISSB first reporting year differ, the reliefs may apply to different periods.
• Value chain data: Both frameworks acknowledge the difficulty of obtaining value chain data, but the specific relief provisions and documentation requirements differ.

The practical advice: map your transition relief elections under each framework separately, then check for conflicts before finalising your reporting approach. Do not assume that electing a relief under ISSB Standards automatically preserves your ESRS compliance, or vice versa.

ISSB Adoption: Where Mandatory Compliance Applies in 2026

As of June 2025, 36 jurisdictions have adopted or are taking steps to introduce ISSB Standards, according to the IFRS Foundation's jurisdictional profiles. Of 17 published profiles, 14 target full adoption of ISSB Standards, two target climate-only adoption, and one targets partial incorporation.

ISSB Chair Emmanuel Faber stated in June 2025: "We have seen new jurisdictions joining the initial cohort of ISSB adopters every month, with a total of 36 today."

For preparers assessing mandatory compliance timelines, the key jurisdictions to track include:

• Australia: Australian Sustainability Reporting Standards (ASRS) require mandatory ISSB-aligned disclosures for large entities, with phased implementation underway.
• Hong Kong: HKFRS S1 and S2 finalised, phased implementation in progress.
• Canada: CSDS 1 and CSDS 2 aligned with ISSB Standards (note: adoption currently paused by Canadian Securities Administrators as of mid-2026).
• Japan, Brazil, Chile, Malaysia, Nigeria, and others: Confirmed adoption pathways per IFRS Foundation profiles.

The IFRS Foundation publishes jurisdictional profiles only when a jurisdiction's approach is finalised and no longer subject to consultation, so published profiles represent confirmed decisions rather than proposals. Use the IFRS Foundation's jurisdictional profiles page as your primary reference for mandatory compliance dates by jurisdiction.

For companies in jurisdictions where mandatory adoption has not yet occurred, the IFRS Foundation has published a guide for entities voluntarily applying ISSB Standards to support early adoption and investor communication.

The EU Omnibus Package: What to Plan For Now

The EU Omnibus I package, proposed in February 2025, is still moving through EU legislative process as of mid-2026. It proposes to raise CSRD thresholds, reduce mandatory ESRS datapoints, and delay wave-2 and wave-3 applicability. This directly affects which entities must comply with ESRS and how many datapoints they must report.

The Interoperability Guidance predates the Omnibus proposals and has not been updated to reflect them. Preparers should treat it as potentially requiring revision once Omnibus is finalised.

What is safe to plan for now:

• Wave-1 in-scope entities (large EU public-interest entities already reporting under CSRD) should continue building dual-framework compliance infrastructure. Omnibus does not propose to remove their ESRS obligations.
• Wave-2 and wave-3 entities face genuine uncertainty about whether and when ESRS will apply to them. The pragmatic approach is to continue building data collection capabilities aligned with both frameworks, since ISSB adoption in your non-EU jurisdictions may create mandatory reporting obligations regardless of what Omnibus does to CSRD scope.
• Voluntary reporters in ISSB-adopting jurisdictions should not wait for Omnibus finalisation before beginning IFRS S1/S2 compliance work. The ISSB framework is stable; the ISSB has committed to embedding IFRS S1 and S2 before moving to new standards.

For a detailed analysis of Omnibus impacts on CSRD scope, see Finrep's CSRD reporting guide for US companies with EU operations.

Building a Single Integrated Data Collection Process

The biggest efficiency gain in dual-framework reporting comes from a single data architecture, not two parallel workstreams. Here is a practical sequence for building it:

1. Start with the ESRS double materiality assessment. It is more comprehensive than IFRS S1 requires, so completing it first ensures you have not missed any financially material topics. Extract the financial materiality findings for your IFRS S1 materiality documentation.

2. Map your ESRS E1 data collection to the IFRS S2 paragraph mapping in Section 2 of the Interoperability Guidance. For each datapoint, tag it as: (a) common to both frameworks, (b) ESRS-only incremental, or (c) ISSB-only. This tagging drives your disclosure structure.

3. For non-climate ESRS topics (E2-E5, S1-S4, G1), assess financial materiality under IFRS S1. Topics that are financially material require IFRS S1-compliant disclosures using the four-pillar structure. Topics that are impact-material only are ESRS-only disclosures.

4. Check SASB Standards for your industry. IFRS S1 requires preparers to refer to SASB Standards when identifying material sustainability topics. Cross-reference SASB metrics against your ESRS datapoints to identify any ISSB-required industry-specific disclosures not covered by ESRS.

5. Map transition relief elections separately for each framework, then reconcile conflicts before finalising your reporting approach.

6. Align sustainability data with financial statement assumptions. Both ESRS and ISSB Standards require connectivity between sustainability disclosures and financial statements, including consistent use of assumptions, discount rates, and scenario inputs. PwC's connectivity guidance (updated January 2026) addresses this requirement in detail.

7. Determine assurance requirements by jurisdiction. ESRS requires limited assurance with a pathway to reasonable assurance. ISSB Standards leave assurance to jurisdictions. If your ISSB-jurisdiction regulator requires assurance, confirm that your assurance provider is familiar with both frameworks and that the scope of their engagement covers both sets of requirements.

Assurance and Presentation: The Two Gaps No One Talks About

Assurance obligations differ and cannot be assumed to overlap. ESRS mandates limited assurance on sustainability reporting, with a regulatory pathway to reasonable assurance. ISSB Standards leave the assurance question entirely to individual jurisdictions. For a preparer in, say, Australia (mandatory ISSB) with EU subsidiaries (mandatory ESRS), the assurance requirements may differ in scope, standard, and timing. Engage your assurance provider early to map the combined assurance scope.

Presentation requirements also diverge. ESRS requires sustainability information in the management report, a prescribed location within the annual report. ISSB Standards allow more flexibility, requiring disclosures alongside financial statements but not mandating a specific document location. If you are producing a single sustainability report intended to satisfy both frameworks, confirm that the document structure and location satisfy the ESRS management report requirement and that the ISSB-jurisdiction regulator accepts that format.

FAQ

Can we satisfy IFRS S2 by reporting under ESRS E1? Almost entirely, yes. Almost all IFRS S2 requirements are included in ESRS E1. However, Section 3 of the Interoperability Guidance identifies specific items an ESRS preparer must check to confirm IFRS S2 compliance, and Section 4.2 lists ESRS E1 requirements with no IFRS S2 equivalent. Read the guidance directionally: it is not a blanket equivalence determination.

Does the Interoperability Guidance cover ESRS E2-E5 and S1-S4? No. The guidance covers only climate (IFRS S2 vs. ESRS E1) and general reporting requirements (IFRS S1 vs. ESRS 1 and ESRS 2). For all non-climate ESRS topics, preparers must independently assess IFRS S1 requirements based on financial materiality.

Is the Interoperability Guidance still current given the Omnibus proposals? It is the authoritative reference, but it is a point-in-time document published on 2 May 2024. The guidance itself notes that future amendments to ESRS or ISSB Standards may change the analysis. Omnibus proposals are not yet reflected in it. Treat the guidance as the current best reference while monitoring Omnibus finalisation.

What does the ISSB's Transition Implementation Group (TIG) do? The TIG discusses implementation questions in a public forum and informs the ISSB about practical challenges. Unlike the IFRS Interpretations Committee, it does not publish formal interpretive guidance. TIG discussions are public and can inform your implementation approach, but they do not have the status of authoritative guidance.

When does mandatory ISSB compliance apply to us? It depends entirely on your jurisdictions. The IFRS Foundation's jurisdictional profiles (published only when adoption decisions are final) are the most reliable reference. As of June 2025, 36 jurisdictions have adopted or are taking steps to adopt ISSB Standards.

Should we start with ESRS and layer on ISSB, or vice versa? For entities with mandatory ESRS obligations, start with ESRS. The double materiality assessment is more comprehensive, and ESRS E1 covers almost all of IFRS S2. Use the Interoperability Guidance to identify the incremental ISSB requirements you need to add. For entities with mandatory ISSB obligations but no current ESRS requirement, start with IFRS S1/S2 and use the Interoperability Guidance in the Section 4 direction to identify what ESRS E1 would require on top.

For the full IFRS S1 and S2 disclosure checklist, see Finrep's IFRS S1 and S2 Disclosure Checklist for Preparers (2026).