SASB vs ISSB: Key Differences Explained

Quick Comparison

What is SASB?

The Sustainability Accounting Standards Board developed 77 industry-specific standards identifying the sustainability topics most likely to be financially material for companies in each industry. Founded in 2011 with an explicit parallel to FASB's role in financial accounting, SASB filled a gap by providing quantitative, comparable metrics tailored to specific sectors — from healthcare delivery to semiconductors to commercial banks.

On average, each SASB standard includes six disclosure topics and 13 metrics for its industry. The metrics are prescriptive: specific units, calculation methodologies, and definitions. This granularity enables direct comparison between companies in the same industry, which was SASB's primary design objective. The standards draw on 26 general issue categories grouped into five sustainability dimensions, with each standard reflecting only the issues financially material to that particular industry.

In 2022, the IFRS Foundation consolidated the CDSB (in January) and the Value Reporting Foundation (in August), which housed the SASB Standards and the Integrated Reporting Framework, to support the newly formed ISSB. The TCFD, whose recommendations IFRS S2 builds on, disbanded in October 2023, and the IFRS Foundation took over monitoring of companies' climate disclosures. SASB Standards continue to be maintained and are explicitly referenced within IFRS S1 as a resource for identifying industry-specific disclosures.

What is the ISSB?

The International Sustainability Standards Board was established by the IFRS Foundation in November 2021 to create a global baseline for sustainability-related financial disclosures. Its inaugural standards, IFRS S1 (General Requirements) and IFRS S2 (Climate-related Disclosures), were issued in June 2023.

IFRS S1 sets out the overall framework: companies must disclose sustainability-related risks and opportunities that could reasonably affect enterprise value, organized around Governance, Strategy, Risk Management, and Metrics & Targets. IFRS S2 provides specific climate requirements built on the TCFD framework. Both standards incorporate SASB's industry-specific approach — IFRS S1 directs entities to consider SASB Standards when identifying relevant sustainability topics and metrics, and IFRS S2 includes industry-based climate metrics derived from SASB.

The ISSB is designed for jurisdictional adoption. Countries adopt or endorse ISSB standards and integrate them into their securities regulations or listing rules, often making compliance mandatory for covered entities. As of April 2026, 28 jurisdictions had adopted them in some form, though not always as a mandate: in May 2026, Brazil's securities regulator (CVM Resolution 244) made its ISSB-based reporting voluntary on a comply-or-explain basis.

Key Differences

1. Relationship: Parent and Component

SASB is now a component of the ISSB ecosystem, not an independent alternative. Think of it as SASB's industry-specific metrics being one input into the broader ISSB architecture. IFRS S1 paragraph 55 requires entities to refer to and consider the applicability of SASB disclosure topics when identifying sustainability-related risks and opportunities, and IFRS S1 also requires them to consider SASB metrics when no ISSB Standard specifically applies. The relationship is hierarchical, not competitive.

2. Architecture

SASB operates through 77 standalone industry standards, each self-contained. The ISSB uses a layered architecture: IFRS S1 provides the general framework applicable to all entities, IFRS S2 provides climate-specific requirements, and industry-based guidance (drawing from SASB) provides sector-level detail. An entity using ISSB applies all three layers; an entity using SASB applies only its industry standard.

3. Topical Breadth

SASB Standards cover multiple sustainability dimensions per industry — environment, social capital, human capital, business model, and leadership/governance — but only where financially material to that industry. ISSB currently has detailed requirements only for climate (IFRS S2), with other sustainability topics covered by IFRS S1's general requirements; it plans to publish proposed nature-related requirements in October 2026. An entity reporting under ISSB may disclose fewer non-climate sustainability topics than a comprehensive SASB implementation would cover, unless the entity determines those topics are financially material under S1.

4. Governance and Risk Management Disclosures

SASB Standards focus on metrics and targets with limited governance or risk management disclosure requirements. ISSB requires detailed governance disclosures (board oversight, management roles), strategy disclosures (business model impacts, scenario analysis), and risk management disclosures (identification, assessment, and management processes). These qualitative disclosures around governance and process are a significant expansion beyond SASB's quantitative focus.

5. Financial Statement Connectivity

ISSB standards require explicit connection between sustainability disclosures and financial statements — publication at the same time as the financial statements, explanations of how the information connects, and data and assumptions consistent with the financial statements to the extent possible. SASB Standards were designed for inclusion in SEC filings but did not prescribe the same degree of financial statement integration the ISSB demands.

6. Jurisdictional Authority

SASB Standards were adopted voluntarily, without regulatory mandate. The ISSB is being adopted into law by national securities regulators. When a jurisdiction adopts IFRS S1 and S2 as issued, considering the SASB-derived industry metrics becomes part of a legal obligation rather than a voluntary commitment, although companies still judge which metrics apply to them.

Which One Do You Need?

SASB remains useful as a practical tool for identifying industry-specific metrics and preparing for ISSB compliance. If your jurisdiction hasn't yet adopted ISSB, SASB provides a well-established set of investor-focused metrics that will transition smoothly to the ISSB framework.

ISSB is the destination. If your jurisdiction has adopted or is adopting ISSB-based requirements, your compliance obligation is to IFRS S1 and S2, with SASB industry metrics informing the industry-specific component. New reporting programs should target ISSB standards directly.

Both, practically speaking. Since SASB feeds into ISSB, using SASB's industry metrics as part of your ISSB implementation is the intended approach, not a redundancy.

Can You Use Both?

They're designed to work together. An entity complying with IFRS S1 and S2 will naturally use SASB industry metrics as part of that compliance. The IFRS Foundation says companies that have used the SASB Standards are well positioned to apply the ISSB Standards; in practice, a SASB reporter transitions by layering on the governance, strategy, risk management, and general disclosure requirements of IFRS S1 and the specific climate requirements of IFRS S2.

For entities not yet subject to ISSB mandates, continuing to report under SASB is a solid interim strategy. The metrics you're already collecting and disclosing will carry forward into ISSB compliance with minimal rework.

Council Fire's Perspective

We tell clients to stop thinking about SASB vs. ISSB as a choice — it's an evolution. If you've been reporting under SASB, you've built a strong foundation of industry-specific, financially material metrics. The ISSB transition adds structure around those metrics: governance frameworks, risk management processes, strategy articulation, and financial statement linkage. It's an expansion of the reporting envelope, not a replacement of its contents.

For organizations that haven't started with either, we recommend going directly to ISSB and using SASB's industry standards as the metric identification tool they were designed to be. The ISSB's adoption momentum makes it the standard that will matter for regulatory compliance, and building your program around SASB alone would leave gaps in governance and process disclosures that ISSB requires.

Frequently Asked Questions

Are SASB Standards being retired?

No. The ISSB has committed to maintaining SASB Standards as a resource for entities applying IFRS S1 and S2. The standards are periodically updated through the ISSB's maintenance process: the ISSB amended them in December 2023 to improve their international applicability (effective for periods from January 1, 2025), and its further proposed amendments, published as exposure drafts in July 2025 and March 2026, were still under review in September 2026. However, SASB's role has shifted from a standalone framework to a component of the ISSB ecosystem.

If I already report under SASB, how do I transition to ISSB?

The IFRS Foundation explains how SASB Standards fit into ISSB reporting in the Accompanying Guidance to IFRS S1 and in its July 2025 educational material on industry-based guidance. The core steps are: (1) continue using your SASB industry metrics as part of the Metrics & Targets pillar, (2) add governance disclosures per IFRS S1, (3) add strategy and risk management disclosures per IFRS S1 and S2, (4) ensure financial statement connectivity, and (5) apply the TCFD-derived climate requirements in IFRS S2.

Do SASB's 77 industry classifications apply under the ISSB?

The ISSB uses the SASB industry classification system (SICS) as the basis for industry-specific guidance referenced in IFRS S1 and the industry-based metrics in IFRS S2. Companies identify their industry under SICS and consider the applicability of the corresponding topics and metrics. The ISSB may evolve the classification system over time, but currently it mirrors SASB's structure.