Double Materiality

Where most first-time assessments go wrong

We've seen about half the first-time CSRD reporters run their double materiality assessment as a single workshop and produce one blended score per topic. The result is a list of "material" sustainability matters with no traceable logic showing whether each topic was included for its impact on people and the environment or for its financial effect on the entity (or both). When the assurance provider asks for that logic (and they will), the file falls apart.

Double materiality is the principle under the CSRD and ESRS requiring an entity to report sustainability information that is material from two distinct perspectives: impact materiality (actual or potential effects of the entity's activities on people or the environment) and financial materiality (sustainability-related risks and opportunities that trigger or could reasonably trigger material financial effects on the entity). ESRS 1.38 governs impact materiality, assessed by severity (scale, scope, irremediable character, and for potential impacts, likelihood). ESRS 1.49 governs financial materiality, assessed by effects on cash flows, access to finance, cost of capital, and asset values.

A sustainability matter needs to be material from only one perspective to require disclosure. The entity documents the assessment in its sustainability statement and, under ESRS 2 IRO-1, discloses the process it followed. An entity identifies its impacts, risks, and opportunities (the IRO assessment) across the sustainability matters covered by the topical ESRS standards. The assurance provider (initially under limited assurance, shifting to reasonable assurance by October 2028) evaluates whether the assessment process and the resulting scope of disclosures are free from material misstatement. ISSA 5000, effective for periods beginning on or after 15 December 2026, provides the global framework for that assurance engagement.

Worked example: Schaefer Elektrotechnik AG

Client: German electronics manufacturer, FY2026, revenue EUR 310M, IFRS reporter, first-time CSRD reporter (large public-interest entity). Schaefer's sustainability team conducts a double materiality assessment across all ESRS topical standards.

Step 1 — Map the value chain and identify IROs

Schaefer maps its upstream supply chain (rare-earth mineral sourcing from certified refiners in three countries), its own operations (two production sites in Bavaria, one in Poland), downstream use and disposal of electronic components, and end-of-life recycling obligations in the EU market. The team identifies 14 potential sustainability matters from the ESRS topic list, covering climate change, pollution, own workforce, and workers in the value chain.

Documentation note: record the value chain mapping alongside the sources consulted (ESRS AR 16 sector guidance, internal procurement data, customer surveys, and peer benchmarking). Include the initial long list of 14 IROs per ESRS 2 IRO-1.

Step 2 — Assess impact materiality

For each IRO, the team scores severity on scale (intensity of the impact), scope (geographic or population breadth), irremediable character (whether the harm can be reversed), and likelihood (for potential impacts only). Schaefer's rare-earth sourcing scores high on irremediable character because environmental contamination at mining sites is difficult to reverse. The team flags four topics as impact-material: climate change (ESRS E1), pollution (ESRS E2), own workforce (ESRS S1), and workers in the value chain (ESRS S2).

Documentation note: record the severity scoring matrix, the threshold applied to distinguish material from non-material, the rationale for each topic assessed as material per ESRS 1.43–44, and the rationale for each topic assessed as not material. For the human rights topics, confirm that severity took precedence over likelihood per ESRS 1.45.

Step 3 — Assess financial materiality

Next, the team evaluates whether sustainability-related risks or opportunities could trigger material financial effects. Schaefer identifies two additional topics as financially material but not impact-material: resource use and circular economy (ESRS E5), because rising input costs for scarce components affect gross margins by an estimated EUR 4.2M per year, and business conduct (ESRS G1), because anti-bribery compliance in three jurisdictions creates a quantifiable legal exposure.

Documentation note: record the financial materiality assessment per ESRS 1.49–52, linking each risk to a cash flow line or balance sheet item. Document the quantitative thresholds used and the evidence supporting the EUR 4.2M margin impact.

Step 4 — Finalise the material topics and determine disclosures

Combining both assessments produces six material topics. For each, Schaefer identifies the applicable ESRS disclosure requirements and datapoints. Ten remaining topics from the initial long list are documented as not material, with reasons.

Documentation note: record the final list of material topics with a cross-reference to the applicable ESRS topical standard. Retain the documentation for topics assessed as not material per ESRS 2 IRO-2. This documentation forms the basis of the assurance provider's evaluation under ISSA 5000.

Schaefer's double materiality assessment produces six reportable topics from an initial list of 14. The assessment is defensible because each topic carries a documented severity or financial-effect analysis traceable to internal data and external benchmarks. At firms like ours, we treat that traceability as the single most important quality of the file. Without it, the assurance provider has nothing to test.

Why it matters in practice

• Teams frequently conduct the impact materiality assessment and the financial materiality assessment as a single undifferentiated exercise, producing a blended score rather than two separate evaluations. ESRS 1.38 and ESRS 1.49 define impact materiality and financial materiality as distinct concepts with different assessment criteria (severity versus financial effect). Collapsing them into one score obscures whether a topic was included for its impact or its financial effect (or both), and leaves the assurance provider unable to trace the logic. This is the finding that generates the most pushback from reporting entities, because separating the two assessments feels like duplicating work. It is not. It is the only way to produce an auditable trail.
• The threshold for "material" is often set without documenting why that threshold was chosen. EFRAG's materiality assessment implementation guidance (IG 1) stresses that the entity must explain the criteria and scales it applied, including the cut-off points separating material from non-material. An undocumented threshold gives the assurance provider no basis to evaluate whether the assessment is reasonable, and it exposes the entity to challenge from regulators reviewing the sustainability statement. We've seen entities SALY the prior-year threshold without reconsidering whether the business or regulatory environment changed. That is a tick box exercise, not an assessment.

Double materiality vs. single materiality (financial materiality only)

The distinction matters because an entity reporting under both IFRS Sustainability Disclosure Standards and ESRS may find topics that are impact-material under ESRS but not financially material under IFRS S1. The auditor providing sustainability assurance must understand which framework drives each disclosure to evaluate whether the scope is complete.

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