What Is "Materiality" in ESG, and Why It's the Most Important Word in the Whole Report

Aug 25

8 min read

Every article in this series has quietly depended on one word without fully explaining it. The anatomy piece called materiality "arguably the single most important section" of a report and moved on. The alphabet soup piece used it to separate five standards into two camps. It's time to actually open that word up, because once you understand what "material" means and, more importantly, who decided it, you understand why two companies in the same industry can publish reports that barely overlap, both completely compliant with the rules they're following.

Materiality is not a synonym for "important." It's a specific, technical gatekeeping test, and depending on which version of the test a company applies, a topic like biodiversity, data privacy, or supply chain labor practices can either dominate the report or never appear in it at all, both outcomes correct under the rules being followed.

Where the Word Actually Comes From

Materiality didn't originate in ESG. It's a decades-old concept borrowed from US securities law, and understanding its legal starting point makes the ESG versions much easier to follow.

In 1976, the US Supreme Court decided TSC Industries v. Northway, a case about proxy voting disclosure. The Court's test has been quoted in SEC guidance and case law ever since: a fact is material if there is a substantial likelihood that a reasonable investor would consider it important, one that would have significantly altered the total mix of information available to that investor. The SEC later wrote a version of this directly into its rules, at 17 C.F.R. §230.405 and §240.12b-2, and the Supreme Court reaffirmed the same standard in Basic Inc. v. Levinson in 1988.

Notice what this original definition is built around: a reasonable investor, deciding whether to buy, sell, or vote. It says nothing about the company's impact on the world. That single, narrow, investor-centered definition is the direct ancestor of what ESG standards now call financial materiality, and the tension between that original definition and a newer one is exactly what created "double materiality."

Key takeaway: materiality started as a purely financial, investor-protection concept in securities law, decades before anyone used the term in a sustainability context. Every ESG materiality definition you'll encounter is either a direct descendant of that original test or a deliberate departure from it.

Financial Materiality (Single Materiality): "Does This Affect the Company?"

The question it asks: would this sustainability issue reasonably affect this company's financial performance, cash flows, or access to capital?

This is the version used by SASB, by the old TCFD, by the ISSB's IFRS S1 and S2, and it's the version closest to the original SEC/TSC Industries definition. As covered in the previous article in this series, SASB operationalized this by sorting companies into 77 industry-specific standards, on the logic that water scarcity is financially material to a beverage company in a way it simply isn't to a software company. IFRS S1 makes the connection to the legal origin explicit, directing companies to assess whether a sustainability matter could reasonably be expected to affect the entity's cash flows, its access to finance, or its cost of capital over the short, medium, or long term, language that's a close paraphrase of the reasonable investor test.

Under single, financial materiality, a topic that has no plausible financial consequence for the company simply doesn't need to be reported, even if the company's activities affect that topic significantly. This is the version of materiality that produces the leanest reports: only the topics an investor would actually price into a valuation make the cut.

Key takeaway: financial materiality is a filter aimed at investors. A topic gets in only if it could move the company's own numbers, not because the company itself might be affecting the world in a way somebody else cares about.

Impact Materiality (GRI's Approach): "Does the Company Affect This?"

The question it asks: does this company have a significant actual or potential impact on the economy, environment, or people, regardless of whether that impact ever shows up in the company's own financial statements?

This is GRI's definition, and it is deliberately, explicitly independent of financial consequences. GRI 3: Material Topics 2021, effective since 1 January 2023, defines material topics as those that represent an organization's most significant impacts on the economy, environment, and people, including impacts on human rights. GRI's own guidance states plainly that sustainability reporting under GRI is independent of financial materiality considerations, even though an impact may also become financially material later.

GRI sets out a four-step process for identifying material topics: understand the organization's context (activities, business relationships, and the sustainability landscape it operates in); identify actual and potential impacts across operations and the value chain; assess the significance of those impacts, using severity and likelihood; and prioritize the most significant impacts for reporting. GRI 3 also requires the organization to document that process, including its assumptions, the stakeholders it consulted, and the evidence it gathered, specifically so a reader can evaluate how the list of material topics was actually produced rather than simply trusting the final list.

KPMG Germany's report, examined in the anatomy article earlier in this series, reflects this stakeholder-first logic: its material topics, such as consumer and end-user impact, sit alongside its financial and compliance disclosures rather than being filtered out because they don't move KPMG's own bottom line.

Key takeaway: impact materiality is a filter aimed at everyone else, communities, employees, the environment, not investors specifically. A topic gets in because the company's activities matter to the world, even if the world never sends the company an invoice for it.

Double Materiality: Both Questions, Answered Separately, Under One Roof

The question it asks: both of the above, assessed independently, with a topic qualifying for disclosure if it clears either threshold on its own.

Double materiality is the standard behind CSRD and its detailed rulebook, ESRS. It isn't a blend or an average of the other two; it's a requirement to run both tests and report a topic if it passes either one. ESRS 1, as implemented through EFRAG's official Implementation Guidance 1 (finalized May 2024), defines the two dimensions precisely: impact materiality concerns the undertaking's actual or potential, positive or negative impacts on people or the environment, connected to its own operations and its value chain, while financial materiality applies when a sustainability matter triggers or could reasonably be expected to trigger material financial effects on the company's development, financial position, performance, cash flows, access to finance, or cost of capital. A topic is material under ESRS if it clears either bar, and EFRAG notes the two frequently overlap, since a material impact on people or the environment often generates a financial risk or opportunity in its own right, just not always, and not always on the same timeline.

Each dimension has its own specific test. For impact materiality, ESRS 1 asks about severity, meaning the scale of the impact, its scope, and how irremediable it is, together with the likelihood the impact occurs; for a potential negative human rights impact, severity takes precedence over likelihood, meaning a severe but less likely human rights impact can still be material. For financial materiality, ESRS 1 asks about the magnitude of the potential financial effect, its likelihood, and the time horizon involved, short-term (within a year), medium-term (one to five years), or long-term (beyond five years).

This is why Allianz's materiality process, covered in the anatomy article, surfaced biodiversity as material specifically because of its investment and insurance portfolios: biodiversity loss creates a plausible financial risk to Allianz's underwriting and asset management business (financial materiality) and Allianz's investment decisions have a real effect on biodiversity outcomes (impact materiality). Under a single, GRI-only impact lens, biodiversity might have been included anyway. Under a single, SASB-style financial lens, it likely would only appear if Allianz's own analysts judged it a pricing risk. Under double materiality, it gets a formal seat regardless of which lens got there first.

Key takeaway: double materiality doesn't ask "which lens is right." It asks both questions independently and keeps any topic that survives either one, which is exactly why ESRS-based reports tend to be longer and structurally more rigorous than a report built on a single materiality standard.

Why This One Word Explains the Whole Series So Far

Go back to the anatomy article's central claim: three companies, Siemens, KPMG Germany, and Allianz, produced three genuinely different lists of material topics, even though all three are reporting in roughly the same regulatory environment. That wasn't inconsistency. It was three different materiality assessments, run on three different businesses with three different value chains, correctly producing three different answers.

This is also the mechanism behind greenwashing accusations that turn out to be more complicated than they first appear. A company that never mentions a topic a critic thinks it should address isn't necessarily hiding something; it may have run a materiality assessment and genuinely concluded, under whichever standard it follows, that the topic doesn't clear the bar. The place to check that claim isn't the topic itself, it's the materiality assessment's documented methodology, exactly the disclosure GRI 3 and ESRS 1 both require a company to publish alongside its list of material topics.

Key takeaway: materiality is the gate everything else in a report passes through. Metrics, targets, policies, and case studies only exist in a report for topics that already cleared this test, which means the materiality section isn't background information, it's the decision that produced the rest of the document.

How to Read a Materiality Section Like You Know What You're Looking For

A short, practical checklist for the next report you open:

Find the word "single" or "double." If the report doesn't say, check which standard it claims to follow (this series' previous article covers how to spot that quickly). GRI alone signals impact materiality. SASB, TCFD, or ISSB alone signals financial materiality. CSRD or ESRS signals double materiality by law.
Look for the process, not just the results. A credible materiality assessment names its steps: how impacts were identified, who was consulted, how severity or financial magnitude was scored. If a report shows only a finished matrix with no description of how it was built, that's a real gap, not a stylistic choice, since both GRI 3 and ESRS 1 require the process itself to be disclosed.
Check which stakeholders were actually consulted. ESRS and GRI both expect engagement with affected stakeholders, not just internal management judgment. A materiality assessment run entirely by the sustainability team, with no external input listed, is weaker evidence than one that names specific stakeholder groups or engagement methods.
Notice topics that appear in only one dimension. Under double materiality, a company will sometimes disclose that a topic is impact material but not financially material, or vice versa. That distinction, when a report makes it explicit, is usually a sign of a rigorous rather than a performative assessment.
Re-check the list year over year. GRI 3 explicitly expects organizations to review their material topics each reporting period, since a topic's significance can change as the business or its value chain changes. A material topic list that's identical, word for word, three years running is worth a second look.

References

TSC Industries, Inc. v. Northway, Inc., 426 U.S. 438 (1976)
Basic Inc. v. Levinson, 485 U.S. 224 (1988)
US Securities and Exchange Commission, Rule 405 (17 C.F.R. §230.405) and Rule 12b-2 (17 C.F.R. §240.12b-2)
Global Reporting Initiative, GRI 3: Material Topics 2021, effective 1 January 2023, globalreporting.org
Global Reporting Initiative, GRI 1: Foundation 2021
EFRAG, ESRS 1: General Requirements
EFRAG, Implementation Guidance 1 (IG 1): Materiality Assessment, finalized May 2024, efrag.org
European Commission, Directive (EU) 2026/47 (the detailed Omnibus Directive), in force 18 March 2026
IFRS Foundation, IFRS S1: General Requirements for Disclosure of Sustainability-related Financial Information
Siemens AG, Siemens Impact 2025
KPMG AG Wirtschaftsprüfungsgesellschaft, Our Impact Report, Sustainability Report 2024
Allianz SE, 2025 Group Annual Report, Sustainability Statement