ESG Reporting Frameworks Compared, GRI vs ESRS vs ISSB vs CDP vs VSME

The main ESG reporting frameworks answer different questions for different readers. GRI reports a company's impacts to everyone, the ESRS are the EU's legal standard under the CSRD, IFRS S1 and S2 (TSRS in Turkey) serve investors, CDP scores climate and water performance for buyers and investors, and the VSME is a short voluntary standard for smaller companies. This article compares them as they stand in October 2026.

Which ESG reporting framework applies to you

For most companies the choice is made by someone else. Law decides if a company reports under the ESRS or TSRS. Customers decide if you answer CDP, EcoVadis or a VSME-based request. GRI is the one framework companies usually pick on their own, often because a bank, investor or tender asks for a report with a GRI content index.

• EU company with more than 1,000 employees and more than EUR 450 million turnover means the ESRS, mandatory from financial year 2027.
• Listed company, bank, insurer or other named financial entity in Turkey above the KGK thresholds means TSRS, mandatory since 2024.
• Supplier to EU customers means VSME-based data, and often CDP or EcoVadis.
• Company seeking finance or publishing a voluntary report usually means GRI, with climate data aligned to IFRS S2.

Comparison table of ESG reporting frameworks

GRI Standards

The GRI Standards are the oldest and most widely used framework for voluntary sustainability reports. The Universal Standards 2021 (GRI 1, GRI 2 and GRI 3) have applied since 1 January 2023. They require a materiality process focused on impacts, a set of general disclosures on the organisation, and topic disclosures for each material topic.

A report can be prepared "in accordance with" GRI, which requires all relevant disclosures, or "with reference to" GRI for a lighter approach. The topic standards are being replaced one by one. GRI 101 Biodiversity applies from 2026, and GRI 102 Climate Change and GRI 103 Energy take effect on 1 January 2027, replacing the old GRI 305 and GRI 302 disclosures and adding transition plan and just transition requirements.

GRI suits companies that want a credible public report without a legal obligation, and companies that need to show impacts to communities, NGOs and lenders. Its weakness is that investors find it less focused on financial effects.

ESRS under the CSRD

The ESRS are the legal reporting standards for companies under the CSRD. After the Omnibus I Directive (EU) 2026/470, only EU companies with more than 1,000 employees and more than EUR 450 million net turnover are in scope, plus non-EU groups with large EU turnover from financial year 2028.

The revised ESRS, published as Delegated Regulation (EU) 2026/1563, apply from financial year 2027. They cut mandatory datapoints by around 61% compared with the 2023 set, but they keep double materiality at the centre. A topic is reported if it matters for the company's impacts on people and the environment, or for its financial position, or both. This makes the ESRS the broadest framework in scope and the most demanding to audit. Our CSRD and ESRS reporting page explains the scope and timeline.

ISSB standards and TSRS

IFRS S1 and IFRS S2 were issued by the ISSB in June 2023 and became effective for annual periods beginning on or after 1 January 2024. They are not mandatory by themselves. Each jurisdiction decides whether to adopt them, and adoption is spreading through capital market regulators.

Turkey adopted them early. KGK published TSRS 1 and TSRS 2 in December 2023, and they apply to listed companies, banks, insurers and other named entities above set thresholds from 2024. The ISSB amended the greenhouse gas requirements of IFRS S2 in December 2025, effective 1 January 2027, and KGK adopted the same changes into TSRS 2 in July 2026.

The ISSB approach uses financial materiality only. It asks what sustainability risks and opportunities could affect cash flows, access to finance and cost of capital. Climate gets the most detail, with scenario analysis, Scope 1, 2 and 3 emissions and industry-based metrics drawn from SASB. See our TSRS and ISSB reporting service for the Turkish scope rules.

CDP

CDP is a disclosure system, not a reporting standard. Companies answer an annual online questionnaire covering climate change, water security and forests, and receive a score from A to D-. Investors use CDP data, and large buyers ask their suppliers to respond through CDP's supply chain programme.

Since 2024 the questionnaire has been aligned with IFRS S2, so a company that has prepared a TSRS 2 or ISSB-based climate disclosure can reuse much of it. The difference is format. CDP asks precise, structured questions with scoring criteria, which rewards verified emissions data, set targets and evidence of action.

Where EcoVadis fits

EcoVadis is not a reporting framework either, but buyers often treat it as one. It is a commercial rating that scores a company on 21 criteria grouped into four themes (environment, labour and human rights, ethics, and sustainable procurement). The analyst scores the documents you upload, not the answers you type.

That makes EcoVadis a test of evidence rather than of disclosure. A company with a GRI report but no records showing policies in action, such as training logs, audit results or supplier assessments, will score lower than expected. The same evidence library that supports an assured ESRS or TSRS report is what lifts an EcoVadis score.

VSME and the EU voluntary standard

The VSME was developed by EFRAG for small and medium-sized companies and published by the Commission as Recommendation (EU) 2025/1710 in July 2025. It has a Basic Module of core metrics on energy, greenhouse gas emissions, pollution, water, waste, workforce, health and safety and corruption, and a second, larger module for companies asked for more detail by banks or investors.

Omnibus I made a version of it legally relevant. The EU voluntary standard, Delegated Regulation (EU) 2026/1560, is based on the VSME and has been in force since 24 September 2026. From financial year 2027, CSRD reporters cannot require more than its Annex II datapoints from value chain companies with 1,000 employees or fewer. For many Turkish suppliers to EU groups, this short list is the realistic target.

How the frameworks fit together

The frameworks overlap more than their names suggest. GRI and EFRAG have published an interoperability index between GRI and the ESRS, and EFRAG and the IFRS Foundation have published guidance on ESRS and ISSB interoperability, particularly for climate. CDP maps to IFRS S2. VSME metrics are a subset of ESRS datapoints.

The practical lesson is to design one data model, not one per framework. Greenhouse gas emissions calculated under the GHG Protocol and ISO 14064-1 feed all five frameworks. Energy, water, waste, headcount, injury rates and anti-corruption data are shared too. What differs is the materiality lens and the narrative around the numbers.

A sensible order for a company starting from scratch is as follows.

1. Build a greenhouse gas inventory for Scope 1 and 2, with a Scope 3 screening.
2. Collect the VSME Basic Module metrics, which nearly every buyer request will include.
3. Answer CDP or EcoVadis if customers ask, reusing the same data and evidence.
4. Prepare a GRI report, or a TSRS or ESRS report if the law requires one, adding materiality and narrative.

Common mistakes when choosing a framework

The most frequent mistake is starting with a glossy GRI report while a legal TSRS obligation or a customer's VSME request is pending. The second is answering each customer questionnaire from scratch, with different emission factors and boundaries, so that figures disagree across CDP, EcoVadis and the annual report.

A third mistake is copying a parent company's double materiality result into a Turkish TSRS report. TSRS uses financial materiality, so the topic list and depth will differ. Our ESG reporting services start with a short scoping exercise that answers which frameworks apply, in which order, and what data you can reuse.