Environmental, Social, and Governance (ESG) ratings have become a critical input for investors, lenders, and corporate decision-makers. Yet one issue continues to generate confusion and debate across global markets: ESG ratings differ significantly between agencies. A company may score highly with one provider while appearing average or even high-risk under another.

These variations in ESG ratings affect investor decision-making, portfolio construction, risk assessment, and corporate strategy. Understanding why ESG scores are inconsistent across global rating agencies is now essential for anyone using ESG data in 2025 and beyond.

Why ESG Ratings Are Not Consistent Across Global Rating Agencies?

Unlike credit ratings, ESG ratings are not governed by a single global standard. Each agency applies its own methodology, scope, data sources, and interpretation of materiality. This leads to structural differences rather than simple analytical errors.

At a high level, ESG rating divergence reflects different answers to a core question: What does ESG risk or performance actually mean?

How ESG Ratings Differ Between MSCI, Sustainalytics, and S&P?

One of the most common investor questions is why ESG ratings differ between MSCI, Sustainalytics, and S&P. The reason lies in how each agency defines purpose, risk, and impact.

Some agencies focus primarily on financially material ESG risks, asking how environmental or social issues could affect a company’s future cash flows. Others place greater weight on corporate impact on society and the environment, regardless of immediate financial relevance.

In addition, rating agencies differ in:

How they weight environmental, social, and governance pillars
Whether they assess absolute performance or relative industry risk
How they treat controversies and past incidents
The extent to which forward-looking strategy is considered

As a result, ESG scores are not directly comparable across providers, even when evaluating the same company in the same year.

Read more: Climate-Related Risks Explained: What Businesses Must Understand in 2026

The Role of Materiality in ESG Rating Variations

Materiality is one of the biggest drivers of ESG rating divergence. Each agency defines “material ESG issues” differently, often by sector, geography, and business model.

For example, climate risk may dominate scoring for one agency, while labor practices or governance controls may carry greater influence for another. This leads to variations in ESG ratings that reflect analytical priorities rather than inconsistencies in underlying data.

For investors, this means ESG ratings should be viewed as perspectives, not definitive verdicts.

Data Sources and Assumptions Create Rating Gaps

Another major reason ESG scores are not consistent across global rating agencies is data selection. ESG ratings rely on a mix of:

Company disclosures and sustainability reports
Regulatory filings
Media screening and controversy analysis
Third-party datasets and estimates

When companies disclose limited or uneven ESG data, rating agencies fill gaps using assumptions or proxies. Different assumptions produce different scores, even when agencies start with similar information.

This is particularly relevant for companies operating across multiple regions with varying disclosure requirements.

Impact of ESG Rating Differences on Corporate Investment Strategies

The impact of ESG rating differences on corporate investment strategies is increasingly visible. Companies often find themselves responding to multiple ESG expectations at once, sometimes with conflicting priorities.

This has led many organisations to:

Align ESG strategy with multiple rating frameworks rather than one
Focus on improving underlying ESG performance rather than chasing scores
Strengthen disclosure quality to reduce data gaps and misinterpretation
Use internal materiality assessments to guide capital allocation

Instead of optimising for a single rating, companies are shifting toward long-term resilience and risk management.

How Variations in ESG Ratings Affect Investor Decision-Making?

For investors, variations in ESG ratings affect decision-making in several ways:

Portfolio ESG scores can change dramatically depending on the data provider
Risk assessments may differ across asset managers using different ratings
Engagement priorities may shift based on which ESG issues are flagged as most material
Comparability across markets and sectors becomes more complex

Sophisticated investors increasingly use multiple ESG ratings or complement ratings with internal analysis to form a more complete view of risk and opportunity.

What Investors Should Do About ESG Rating Differences?

Rather than treating ESG ratings as absolute measures, investors are advised to:

Understand each rating agency’s methodology and assumptions
Use ESG ratings as screening tools, not final investment decisions
Combine ESG scores with financial analysis and engagement insights
Focus on trends and changes over time rather than single scores

In this context, ESG ratings become inputs into decision-making, not substitutes for judgment.

The Future of ESG Ratings: Convergence or Continued Divergence?

While regulatory frameworks and sustainability reporting standards are becoming more aligned globally, ESG ratings are unlikely to fully converge in the near term. Differences in philosophy, scope, and intended audience will continue to shape how agencies score companies.

What is changing is transparency. Investors and corporates now demand clearer explanations of how ESG ratings are constructed and how scores should be interpreted.

Subscribe to our newsletter for more insights, case studies, and ESG intelligence.

Explore ESG Solutions on our marketplace - OneStop ESG Marketplace.

Keep abreast of the top ESG Events on OneStop ESG Events.

OneStop ESG Educate: Your go-to source for top ESG courses and training programs tailored to your needs.

Stay informed with the latest insights on OneStop ESG News.