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What Is the ISSB. And Why Does It Matter for Global Sustainability Reporting?

What Is the ISSB. And Why Does It Matter for Global Sustainability Reporting?

As sustainability reporting becomes a regulatory priority around the world, many organisations are navigating a growing patchwork of standards. Enter the International Sustainability Standards Board (ISSB) — a global effort to bring consistency, clarity, and comparability to how companies report on sustainability and climate-related risks.

A Global Baseline for Sustainability Reporting

The ISSB was established by the International Financial Reporting Standards (IFRS) Foundation to create a unified, investor-focused framework for sustainability disclosures. It launched two foundational standards in 2023:

  • IFRS S1: General Requirements for Disclosure of Sustainability-related Financial Information
  • IFRS S2: Climate-related Disclosures

Together, these standards aim to provide a consistent baseline for sustainability reporting that can be used globally, reducing duplication while allowing room for local requirements or sector-specific disclosures.

Why ISSB Matters

The ISSB’s standards are designed to improve transparency around how sustainability issues affect enterprise value. For investors, regulators, and stakeholders, this means better access to decision-useful information. For companies, it offers a clearer path to compliance and a stronger foundation for aligning with other frameworks — such as CSRD in Europe or the SEC’s proposed rules in the U.S.

Countries Already Adopting the ISSB Standards

Almost 40 jurisdictions, representing 57% of global GDP have already signalled support or are moving toward adoption. These include:

  • United Kingdom – The UK plans to endorse the ISSB standards and integrate them into its sustainability disclosure requirements.
  • Canada – Canada’s new Canadian Sustainability Standards Board (CSSB) is working closely with the ISSB to tailor the standards for national implementation.
  • Australia – The Australian Sustainability Reporting Standards (AASB S1 & AASB S2) were formally approved in September 2024 by the Australian Accounting Standards Board.
  • Japan – Japan’s Financial Services Agency has indicated its intention to use the ISSB as the foundation for future climate disclosure rules.

Other countries, including Brazil, Singapore, and Mexico, are also aligning or considering alignment with the ISSB framework.

ISSB – Interoperability Across Jurisdictions

In 2024, the IFRS Foundation and EFRAG published a joint guidance covering the alignment between the ISSB Standards and ESRS. EFRAG and the IFRS have worked hard to reduce repetition for companies that may be required to report under the CSRD.

The guidance describes the alignment of general requirements and key concepts as well as providing information about the alignment of climate disclosures.

What Should Companies Do Now?

Even in jurisdictions where ISSB standards aren’t yet mandatory, companies should view them as a best-practice foundation for future reporting. Key steps to prepare include:

  • Understand the disclosure requirements under IFRS S1 and S2
  • Undertake a materiality assessment to identify sustainability-related material risks and opportunities
  • Begin assessing internal capabilities and data gaps
  • Align risk management, governance, and strategy disclosures with the ISSB approach
  • Explore technology and platforms that can support ISSB-aligned reporting

Download our free Interactive Non-financial Reporting Checklist. >

How Achilles Can Help

Achilles supports organisations preparing for ISSB reporting with:

  • Comply360° – An AI-powered solution that collects and maps sustainability data across frameworks, including ISSB.
  • Carbon Accounting – Tools and assessments aligned with IFRS S2 and broader sustainability metrics.
  • ESG Audits  – Desktop and site based audits that provide high levels of assurance for companies adopting an OECD-aligned risk-based approach.
  • Supplier Data Management – Validated, audit-ready ESG data from across the value chain.

The ISSB is the foundation for global consistency in sustainability reporting. Getting ready now puts your organisation ahead of the curve. Get started with a non-obligation chat with an Achilles consultant.

Get started with a non-obligation chat with an Achilles consultant.