The Alphabet Soup: GRI vs SASB vs TCFD vs ISSB vs CSRD, Finally Explained
- 2 days ago
- 11 min read
Open the back of almost any ESG report and you’ll find a small paragraph, usually in tiny font, listing three or four acronyms the company claims to follow. GRI. SASB. TCFD. ISSB. CSRD. It reads like the report is checking boxes on a form nobody explained to you. It isn’t random. Each of these names is a different organization asking a different question, for a different audience, and once you know which question each one is asking, the whole alphabet soup stops being confusing and starts being useful information in its own right.
This article answers three things for each standard: what it actually requires, who actually uses it, and why, and it uses real company disclosures, not hypotheticals, to show it. It builds directly on the anatomy piece in this series. If that article showed you the skeleton of a report, this one explains which rulebook built that skeleton in the first place.
The one question that explains almost everything
Before the details, one distinction does more work than any other: who is the report written for?
Investor-focused standards (SASB, TCFD, ISSB) ask: which sustainability issues could affect this company’s financial performance? This is called financial materiality, sometimes “single materiality.”
Stakeholder-focused standards (GRI) ask: how does this company affect the economy, environment, and people, regardless of whether that affects its share price? This is called impact materiality.
CSRD/ESRS asks both at once. That’s what “double materiality” means in practice: a topic is material if it’s financially material, impact material, or both.
Keep that one distinction in mind. It explains almost every difference you’re about to read.
GRI: The Global Reporting Initiative
What it is? GRI is an independent, Amsterdam-headquartered nonprofit, founded in 1997 in the wake of the Exxon Valdez oil spill, that publishes the GRI Standards, developed by its Global Sustainability Standards Board (GSSB). It’s the oldest of the frameworks in this article, and the most widely adopted worldwide.
What it actually requires? GRI is built from three layers: Universal Standards (apply to every reporting organization, covering governance, strategy, and ethics), Sector Standards (industry-specific, covering areas like oil and gas or mining), and Topic Standards (specific issues like GRI 305 for emissions or GRI 403 for occupational health and safety). A company reporting “in accordance with” GRI has to run a materiality assessment, disclose its most significant impacts, and report using the specific indicators tied to each material topic it identifies.
Who uses it, and why? GRI is voluntary everywhere; no government mandates it directly. Despite that, GRI states its standards are used by more than 14,000 organizations in over 100 countries, and a KPMG survey found 78% of the world’s 250 largest companies by revenue used GRI in their sustainability reporting. Companies gravitate toward GRI because it’s the only major framework built explicitly around stakeholder impact rather than investor risk, which makes it the natural fit for a company whose sustainability reporting is aimed at customers, communities, NGOs, and employees as much as shareholders. KPMG Germany’s own Impact Report, covered in the previous article in this series, maps its material topics against GRI-style stakeholder categories alongside ESRS codes, a common pairing for European companies that want both audiences covered.
Key takeaways
GRI answers “how does this company affect the world,” not “how does the world affect this company financially.”
It’s voluntary but extremely widely adopted, especially outside the US.
Its modular structure (Universal, Sector, Topic) is designed so a company only reports the topic-level detail relevant to what it does.
Since 2022, GRI and the IFRS Foundation have formally worked to make GRI disclosures reusable inside ISSB-based reports, more on that below.
SASB: The Sustainability Accounting Standards Board
What it is? SASB was founded in 2011 with a very different starting question than GRI: not “what does this company impact,” but “what sustainability issues are financially material to this specific industry.” SASB built 77 separate industry standards across 11 sectors, on the logic that water scarcity is financially material to a beverage company in a way it simply isn’t to a software company, so a single universal checklist doesn’t serve investors well.
What it actually requires? A company applying SASB identifies which of the 77 industry standards fits its business (SASB itself assigns industries), then discloses the specific, pre-defined financially material metrics for that industry, no more, no less. It’s narrow by design: SASB doesn’t ask a mining company to report on, say, its data privacy practices, because that’s not the standard’s judgment of what’s financially material to a mining company’s investors.
Who uses it, and why? SASB is the standard of choice for US-listed companies communicating to investors, and it shows up constantly in SEC filings. Publishing group RELX discloses using the SASB standard specifically written for its assigned sector, Professional and Commercial Services. Aerospace and defense manufacturer Moog Inc. adopted SASB standards specifically “to establish investor-grade ESG protocols and metrics,” publishing its first SASB disclosure for the Aerospace and Defense industry standard in December 2022. Industrial manufacturer IDEX Corporation has aligned its disclosures with SASB’s sector standards since 2021. The pattern across all three: none of them are EU companies under CSRD, all of them frame SASB explicitly as a tool for investors, not the general public.
Key takeaways
SASB’s whole design philosophy is industry-specific financial materiality. It only asks what matters to your industry’s investors.
It’s the standard most associated with SEC filings and US capital markets.
Since August 2022, SASB is no longer independently governed. It was absorbed into the IFRS Foundation, and today it operates as a component referenced inside ISSB standards rather than a fully separate body, though its 77 industry standards are still actively used and cited by name.
TCFD: The Task Force on Climate-related Financial Disclosures
What it is? TCFD was created in 2017 at the request of the G20’s Financial Stability Board, specifically to standardize how companies disclose climate-related financial risk. It’s narrower than GRI or SASB in scope, climate only, but it introduced a four-pillar structure (Governance, Strategy, Risk Management, Metrics and Targets) that later frameworks borrowed wholesale.
What it actually requires, and its unusual status today? TCFD’s four pillars ask a company to disclose: who governs climate risk internally, how climate risk affects strategy under different warming scenarios, how climate risk is identified and managed, and which metrics and targets track it. Here’s the part that surprises people: TCFD no longer formally exists. In July 2023 the Financial Stability Board announced TCFD’s work was complete, and the task force formally disbanded in October 2023, with its monitoring role transferred to the IFRS Foundation. Its recommendations weren’t abandoned, they were fully absorbed into IFRS S2, the ISSB’s climate standard. A company applying IFRS S2 automatically satisfies TCFD; there’s no separate TCFD reporting left to do.
Who uses it, and why it still appears on reports? Despite being formally dissolved, “TCFD-aligned” still appears constantly in 2025 and 2026 reports, largely because so many companies built years of internal reporting infrastructure around its four pillars and the label remains instantly recognizable to investors. IDEX Corporation’s 2024 Sustainability Report explicitly lists “SASB, TCFD and GRI-aligned disclosures” together, using TCFD as shorthand for its climate governance structure even though the task force itself no longer exists to monitor it.
Key takeaways
TCFD is the historical origin of the “governance, strategy, risk management, metrics and targets” structure you’ll see everywhere in climate disclosure.
It formally disbanded in October 2023. What used to be “TCFD reporting” is now legally IFRS S2 reporting.
Companies keep using the TCFD label informally because it’s a recognizable shorthand, not because there’s still an active TCFD standard to comply with.
ISSB (IFRS S1 and S2): The International Sustainability Standards Board
What it is? The ISSB was created by the IFRS Foundation, the same body behind global accounting standards, in November 2021 at COP26. Its explicit mandate was to end the fragmentation of investor-focused sustainability reporting by consolidating the Climate Disclosure Standards Board (CDSB), the Value Reporting Foundation (which housed SASB), and the TCFD’s climate framework into one coherent baseline. It’s the newest standard in this article and, for investor-facing reporting outside the EU, increasingly the most important.
What it actually requires? The ISSB published two standards in June 2023, effective from January 2024: IFRS S1, general requirements for disclosing sustainability-related risks and opportunities that could reasonably affect a company’s cash flows or cost of capital, and IFRS S2, which applies that same logic specifically to climate. IFRS S2 fully incorporates the old TCFD recommendations, and IFRS S1 explicitly directs companies to “refer to and consider the applicability of” SASB’s industry-specific metrics when identifying what’s material. In effect, ISSB is TCFD’s climate architecture plus SASB’s industry-specific detail, reissued as a single global baseline for investors.
Who uses it, and why? ISSB standards are explicitly designed for governments and regulators to adopt into law, unlike GRI or SASB, which are adopted voluntarily by companies. As of early 2026, more than 30 jurisdictions have adopted or are finalizing adoption of ISSB standards, including the UK, Canada, Japan, Australia, Brazil, Nigeria, Singapore, and Chile, with 21 already in effect. Amphenol Corporation, in its FY2025 SEC filing, describes its Sustainability Report as covering board and executive oversight of climate risk “identified in the International Sustainability Standards Board (‘ISSB’) and Climate Scenario Analysis recommendations,” alongside GRI and SASB, a clean real-world illustration of how these standards now sit layered on top of each other in a single report rather than replacing one another cleanly.
Key takeaways
ISSB is the newest, and effectively the successor investor-facing standard: it absorbed TCFD entirely and references SASB directly.
Unlike GRI and SASB, ISSB standards are built to become law when a jurisdiction adopts them, not just a voluntary framework companies opt into.
If you see a company mention “IFRS S1” or “IFRS S2,” you’re looking at the newest generation of investor-focused climate and sustainability disclosure, built on the bones of TCFD and SASB.
CSRD / ESRS: The EU's Mandatory, Double-Materiality Standard
What it is? The Corporate Sustainability Reporting Directive (CSRD) is EU law, not a voluntary framework, and the European Sustainability Reporting Standards (ESRS), developed by EFRAG and formally adopted by the European Commission, are the detailed rulebook that gives CSRD legal teeth. This is the standard covered in depth in the previous articles in this series, so this section focuses narrowly on how it compares to the other four.
What actually makes it different? Two things separate CSRD/ESRS from every other standard on this list. First, it's mandatory law, not something a company opts into, for any company that meets its scope thresholds. Second, it's the only standard that requires double materiality by law: a company must disclose a topic if it's financially material or impact material, covering both the investor-facing and stakeholder-facing questions the other frameworks split apart. That's a large part of why ESRS reports, like Siemens' and Allianz's, tend to be longer and more structurally rigorous than a voluntary GRI or SASB report.
Recent, significant change? CSRD's scope just narrowed substantially. Following the EU's "Omnibus" simplification package, finalized as law on 18 March 2026, CSRD now applies only to EU companies above 1,000 employees and €450 million net turnover, both thresholds required together, a much smaller pool than originally planned. EFRAG's simplified ESRS draft, submitted to the European Commission in December 2025, cuts mandatory data points by roughly 61%. First-time application under the new, simplified rules is expected for financial year 2027. Companies below the new thresholds aren't required to report under CSRD at all, though many will still face pressure from an EFRAG-developed Voluntary SME Standard (VSME) if larger customers or lenders request it.
Who uses it, and why? Every EU company reviewed in this series, Siemens, KPMG Germany, and Allianz, reports under CSRD/ESRS because EU law requires it of them, not because they chose it competitively over GRI or SASB. That's the single biggest structural difference in this whole article: CSRD isn't competing for adoption the way GRI, SASB, and ISSB are. It's compliance.
Key takeaways
CSRD/ESRS is EU law, not a voluntary standard, which makes "why do they use it" a different kind of question than for the other four.
It's the only standard on this list built around mandatory double materiality by law.
Its scope just shrank significantly under the 2026 Omnibus reform: roughly 1,000+ employees and €450 million+ turnover, with first reporting under the simplified rules expected for FY2027.
Why They Overlap, and How Regulators Are Actively Reducing the Overlap
The overlap isn’t an accident, and it isn’t being ignored either. Three concrete relationships explain almost everything you’ll see stacked together in a real report:
TCFD is now fully inside IFRS S2. There’s no separate compliance step. A company applying IFRS S2 has already met TCFD’s requirements by definition, since IFRS S2 was built by directly incorporating TCFD’s four-pillar structure.
SASB is now referenced inside IFRS S1. SASB wasn’t deleted when it joined the IFRS Foundation in 2022, its 77 industry standards are still actively maintained and cited by name, but IFRS S1 now formally directs companies to “refer to and consider” SASB’s industry metrics as the default source of industry-specific detail.
GRI and ISSB are being deliberately aligned, not merged. GRI and the IFRS Foundation signed a Memorandum of Understanding in 2022, a joint statement on interoperability in May 2024, and a further joint statement on 26 May 2026 specifically clarifying which disclosures can be reused across both standards (“common disclosures”) versus which serve genuinely different purposes and must be assessed separately (“complementary disclosures”). A concrete example: GRI and the IFRS Foundation have jointly confirmed that GRI 305 (Emissions) and IFRS S2’s GHG emissions requirements are highly aligned, since both are built on the same underlying GHG Protocol, so a company already disclosing Scope 1, 2, and 3 emissions under GRI is largely already positioned to meet IFRS S2’s emissions disclosures without duplicating the work.
CSRD sits on top of, and draws from, all of it. ESRS wasn’t built in a vacuum. It shares substantial DNA with GRI’s impact-materiality thinking and with TCFD’s climate governance structure, layered underneath the EU’s own legal double-materiality requirement, which is why a company reporting under ESRS, like Siemens or Allianz, can often map its material topics back to GRI and TCFD-style categories in the same table, exactly what KPMG Germany’s report does.
Key takeaways
Overlap exists because every newer standard was deliberately built on the last one’s architecture, not created from scratch.
Two absorptions are complete: TCFD into IFRS S2, and SASB into ISSB’s IFRS S1 references.
One alignment is ongoing and formalized: GRI and ISSB remain separate, deliberately, but are actively mapped against each other through joint IFRS Foundation and GRI publications.
CSRD/ESRS is the most demanding because it’s the only one legally requiring both the investor lens and the stakeholder lens at once.
The Cheat Sheet
Standard | Governing body | Primary audience | Materiality type | Mandatory? | Real example |
GRI | Global Sustainability Standards Board (GSSB) | Broad stakeholders | Impact materiality | Voluntary | KPMG Germany |
SASB | IFRS Foundation (formerly independent) | Investors | Financial materiality, industry-specific | Voluntary (referenced by ISSB) | RELX, Moog Inc, IDEX |
TCFD | Disbanded Oct 2023; folded into IFRS S2 | Investors | Financial materiality, climate only | N/A, absorbed | IDEX (legacy label) |
ISSB (IFRS S1/S2) | International Sustainability Standards Board | Investors | Financial materiality | Voluntary globally, mandatory where adopted into law | Amphenol |
CSRD / ESRS | ESRS European Commission / EFRAG | Investors and stakeholders | Double materiality | Mandatory by EU law (in scope) | Siemens, Allianz |
Keep this cheat sheet with you:
If You Only Remember One Thing
Ask two questions about any report you’re reading: is this company legally required to report this way, or did they choose to, and is this framework asking “how does the world affect this company” or “how does this company affect the world,” or both? Once you can answer those two questions for any acronym in the footnotes, the alphabet soup stops being noise and starts telling you exactly what kind of report you’re holding.
References
Global Reporting Initiative (GRI), “How to Use the GRI Standards,” globalreporting.org
GRI and IFRS Foundation, “Facilitating Efficient Reporting When Using the GRI and ISSB Standards,” jointly published 26 May 2026, ifrs.org
IFRS Foundation, “ISSB and TCFD,” ifrs.org/sustainability/tcfd
IFRS Foundation, “IFRS Foundation Welcomes Culmination of TCFD Work and Transfer of TCFD Monitoring Responsibilities to ISSB,” ifrs.org
IFRS Foundation, “ISSB Proposes Comprehensive Review of Priority SASB Standards,” July 2025, ifrs.org
EFRAG, Draft Simplified ESRS and Final Technical Advice to the European Commission, 3 December 2025
European Commission / Council of the European Union, “Omnibus” Directive, in force 18 March 2026
Corporation, Form 10-K and Form ARS, FY2025, sec.gov
IDEX Corporation, Form DEF 14A, FY2025, sec.gov
RELX PLC, Form 20-F, FY2025, sec.gov
Moog Inc., Form DEF 14A, FY2025, sec.gov
Siemens AG, Siemens Impact 2025
KPMG AG Wirtschaftsprüfungsgesellschaft, Our Impact Report, Sustainability Report 2024
Allianz SE, 2025 Group Annual Report, Sustainability Statement
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