Who the main ESG rating agencies are, what each measures, how their scoring differs, and why GCC companies need to understand the raters that judge them.
Introduction
A company can be rated AAA by one agency and barely average by another — same company, same year. That is the puzzle of ESG ratings: everyone scores them, no two score them the same way, and the stakes keep rising. For GCC companies seeking international capital or supplying multinational buyers, the raters have become gatekeepers. This article explains who they are, what each measures, and why understanding them matters.
What an ESG rating is
An ESG rating is a rating agency’s assessment of a company’s environmental, social and governance performance or risk, expressed as a score or grade. Investors use them to compare companies; buyers use them to vet suppliers; lenders use them in covenants. The catch — and it is a big one — is that different agencies measure different things in different ways.
The main raters
| Rater | Scale | Emphasis |
|---|---|---|
| MSCI | AAA–CCC | ESG risk relative to industry peers |
| Sustainalytics | Risk score (lower = better) | Unmanaged ESG risk exposure |
| S&P Global (CSA) | 0–100 | Corporate Sustainability Assessment; index inclusion |
| ISS ESG | Rating / score | Governance heritage, broad ESG |
| CDP | A–D | Environmental disclosure (climate, water, forests) |
| EcoVadis | Medal + 0–100 | Procurement / supply-chain sustainability |
Each serves a different audience — which is why “improving your ESG rating” first requires knowing which rating.
There is no single “ESG score.” There is a family of ratings, each asking a different question. The first skill is knowing which one your audience is actually reading.
Which rating matters
The honest answer: it depends on the commercial trigger. MSCI and Sustainalytics dominate institutional investor mandates; S&P CSA drives index inclusion; EcoVadis is the procurement gate for European and multinational buyers; and a sustainability-linked loan names a specific rating in its covenant. For a GCC company, the rating to focus on is the one driving its specific requirement — investment, index, supply chain or financing — not all of them equally.
Where to go deeper
This guide is the starting point for a wider series: why ESG ratings differ between agencies, the EU ESG Ratings Regulation bringing raters under supervision, the changing rating landscape in 2026, and the practical question of how to improve your ESG rating.
How ESGweise helps
ESGweise helps GCC companies understand and improve the ESG ratings that matter to them — diagnosing which rating drives their commercial trigger, running methodology-by-methodology gap analysis, and sequencing genuine improvement. See our ESG Rating Improvement practice and our guide to improving your ESG rating.
Conclusion
ESG ratings are a family of different assessments — MSCI, Sustainalytics, S&P, ISS, CDP, EcoVadis — each measuring different things on different scales for different audiences. A single company can hold very different ratings, which is why understanding the landscape is the first step. For GCC companies facing ratings as commercial gates, knowing which rater matters, and why, is where ESG rating improvement begins.
Frequently asked questions
What is an ESG rating?
An ESG rating is an assessment by a rating agency of a company's environmental, social and governance performance or risk, expressed as a score or grade. Investors, lenders and buyers use ESG ratings to compare companies and inform decisions. Crucially, different agencies measure different things in different ways, so a single company can hold very different ratings from different raters.
Who are the main ESG rating agencies?
The most influential include MSCI (an AAA–CCC scale), Sustainalytics (a risk rating where lower is better), S&P Global through its Corporate Sustainability Assessment (a 0–100 score), ISS ESG, CDP (focused on environmental disclosure, A–D), and EcoVadis (a procurement-focused medal and score). Each serves different audiences and uses a different methodology.
Which ESG rating matters most?
It depends on the commercial trigger. MSCI and Sustainalytics are most cited in institutional investor mandates; S&P CSA matters for index inclusion; EcoVadis is the standard procurement gate for European and multinational supply chains; and a sustainability-linked loan covenant names a specific rating. The rating that matters is the one driving your specific commercial requirement.
Why do GCC companies need to understand ESG ratings?
Because ratings increasingly drive access to capital, index inclusion and supply-chain contracts. As GCC companies seek international investment and supply European and multinational buyers, their ESG ratings become commercial gates. Understanding which raters matter, how they score, and how to improve is now a core part of competing internationally.