Curated by: Rubric Advisors
Investing & Markets
ESG Ratings & Scoring Methodologies
Understand how ESG ratings work, why major providers often disagree, and how investors can use, and avoid over-relying on, environmental, social, and governance scores.
ESG Ratings & Scoring Methodologies
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What Are ESG Ratings?
- ESG ratings measure how well a company manages environmental, social, and governance risks
- Agencies pull data from company filings, news, government databases, and direct engagement
- Scores appear as letter grades, numeric scales, or risk categories depending on the provider
- Major providers include MSCI, Sustainalytics, S&P Global, and ISS ESG
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What Are ESG Ratings?
- ESG ratings measure how well a company manages environmental, social, and governance risks
- Agencies pull data from company filings, news, government databases, and direct engagement
- Scores appear as letter grades, numeric scales, or risk categories depending on the provider
- Major providers include MSCI, Sustainalytics, S&P Global, and ISS ESG
Why Ratings Disagree
- Correlations between major raters are surprisingly low, often only 0.4 to 0.6
- Providers define ESG issues differently and weight each factor in their own way
- Data sources vary from company self-reporting to third-party independent data
- A company rated highly by one provider may score poorly with another
Materiality-Based vs. Values-Based Approaches
- Materiality-based ratings focus on ESG factors most likely to affect financial performance
- Values-based approaches judge companies against ethical standards regardless of returns
- SASB identifies industry-specific material issues; GRI takes a broader stakeholder view
- Know which approach a rating uses because it shapes what the score actually measures
Limitations of ESG Scores
- Ratings are backward-looking, assessing current policies and past events, not future direction
- Larger companies with more disclosure resources tend to score higher, creating a size bias
- Combining diverse E, S, and G factors into one score inevitably hides important details
- A fossil fuel company can score high by outperforming peers despite large absolute impact
Controversies and Criticisms
- Critics say ESG ratings have become a box-checking exercise rather than a real measure
- Conflicts arise when rating agencies also sell consulting to the companies they evaluate
- Some studies find weak or inconsistent links between high ESG scores and better returns
- Bundling climate risk with board diversity may dilute focus on either issue
The Push for Standardization
- The ISSB released global sustainability disclosure standards for consistent reporting
- The EU's CSRD mandates detailed ESG disclosure for thousands of European companies
- The SEC adopted climate disclosure rules in 2024, but legal challenges have delayed implementation
- Better disclosure should improve consistency, but full agreement among providers is unlikely
How Investors Should Use ESG Ratings
- Treat ESG ratings as one input, not a definitive judgment of sustainability
- Compare ratings from multiple providers to see where assessments agree or diverge
- Look beyond the headline score at individual E, S, and G pillars for more detail
- Combine scores with research on company strategy, controversies, and forward plans
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