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Environmental, Social and Governance (ESG) - Principles and Practice · Sustainability Audit, ESG Rating and Emerging Mandates from Government and Regulators

ESG Ratings and Rating Providers: Methodology and Limits

Updated 11 October 2026 · Fact-checked

An **ESG rating** is an independent opinion on how well a company manages environmental, social and governance risks. A provider collects data, picks material issues, scores and weights them, then converts the result into a score or grade. Investors use it to screen and compare companies. In exams, explain the steps, the providers and the limits.

Understand ESG Ratings and Rating Providers

An ESG rating is an assessment of a company's exposure to ESG risks and how well it manages them. It is produced by an outside provider, not by the company. Investors, lenders and funds use it as one input to decide where to put money and how to engage with a company.

Think of it as a report card for non-financial risk. A financial rating asks whether a company can repay. An ESG rating asks whether weak practices on emissions, labour, safety, data or board conduct could hurt the company's value or reputation.

Most providers follow a similar path. They collect data from company disclosures such as annual reports and BRSR, from public sources like regulators, courts and news, and sometimes from questionnaires. They then identify material issues for each industry. A steel company and a software company face different risks, so the issues and their weights differ. Each issue is scored, the scores are weighted and added up, and the total is shown as a numeric score, a letter grade or a risk category.

A score is the number a provider calculates, for example out of 100. A rating is the final grade or category given on the basis of that score, for example AAA to CCC or Low to Severe risk. In everyday speech the two words are mixed up, but in an answer you should keep them apart. Some providers rate relative to industry peers. Others measure absolute risk, so the same score can mean different things across providers.

Global providers include MSCI ESG Research, which uses a seven-grade scale from AAA to CCC and rates relative to industry peers, and Sustainalytics (a Morningstar company), which gives an ESG Risk Rating measuring unmanaged risk, where a lower score is better. Others include S&P Global, ISS ESG and CDP, which scores climate, water and forests disclosure. In India, agencies such as CRISIL, ICRA, CARE, Stakeholders Empowerment Services and IiAS have offered ESG ratings or scores. In India, ESG rating providers are now regulated by SEBI, which you should study with the topic on SEBI Regulation of ESG Rating Providers.

Ratings have limits. Providers use different methods, so the same company can get very different results. Ratings depend on disclosed data, which can be incomplete or self-reported. Weights involve judgement, and ratings can lag real events. Large companies with more disclosure often score better, which favours size over performance. Treat a rating as an input, never as proof.

Key rules to remember

Weighted ESG score (general form)
ESG score = Σ (issue score × issue weight), where the weights add up to 100%
This is the common logic, not one provider's exact formula. Each provider sets its own issues and weights.
Score versus rating
Score = number calculated; Rating = grade or category assigned from the score
Use this to answer the difference question in one line.
Direction of scales
MSCI: higher grade (AAA) is better. Sustainalytics: lower risk score is better
Do not say a high number is good for every provider.
Pillar build-up
E score + S score + G score, each weighted by industry materiality, gives the overall score
Pillar weights differ by industry.

How to solve ESG Ratings and Rating Providers questions

Use this method for any question on ESG ratings, whether it asks you to explain, compare or critique.

  1. 1Define an ESG rating in one line: an independent opinion on how well a company manages material ESG risks.
  2. 2State the question's focus: how it is built, who provides it, how it is used, or its limits.
  3. 3For methodology, give the sequence: data collection, material issue selection, scoring, weighting, aggregation, grade or score.
  4. 4Name providers with one feature each, for example MSCI's AAA to CCC scale and Sustainalytics' unmanaged risk measure, then Indian agencies.
  5. 5Link to the Indian context: BRSR as a data source and SEBI regulation of rating providers.
  6. 6Give a balanced view: uses for investors and lenders, then limits such as divergence, data gaps and subjectivity.
  7. 7Close with a conclusion that applies to the facts, for example advice to a company or board.

Quickest way: Define, build, name, limit

When to use it: When time is short and the question is a general explain, discuss or critically examine question on ESG ratings.

  1. Write the definition in two lines.
  2. List the five build steps in a short bullet list.
  3. Name two global and two Indian providers with one feature each.
  4. Write three limits and one improvement, such as a standard methodology and SEBI oversight.
  5. End with a one-line conclusion tied to the question.

Common mistakes in ESG Ratings and Rating Providers

  • Treating ESG score and ESG rating as exactly the same thing.

    Websites and news use the terms loosely.

    Fix: Say a score is the calculated number and a rating is the grade or category assigned. Add that practice varies by provider.

  • Saying a higher number is always better.

    Students assume all scales work like exam marks.

    Fix: Remember that Sustainalytics measures unmanaged risk, so lower is better, while MSCI AAA is the best grade.

  • Writing one fixed formula for how ratings are calculated.

    Students look for a single formula to memorise.

    Fix: Explain the general weighted approach and state that each provider chooses its own issues, weights and data.

  • Listing providers without any methodology detail.

    Memorising names is easier than understanding features.

    Fix: Attach one feature to each name: scale, relative or absolute approach, or focus area.

  • Ignoring limitations or giving only one-sided praise.

    Students think the topic is only about definitions.

    Fix: Always add divergence between providers, reliance on disclosed data, lag, subjectivity and size bias.

  • Confusing ESG ratings with credit ratings or assurance.

    All three involve an outside opinion on a company.

    Fix: State that an ESG rating opines on ESG risk management, while assurance checks reported data and a credit rating assesses repayment ability.

Worked examples

Example 1

Explain how an ESG rating is built and why two providers may give the same company different ratings. (Answer as for a 10-mark question.)

Show the solution
  1. Provision and definition: an ESG rating is an independent opinion on how well a company manages material ESG risks.
  2. Build: the provider collects data from disclosures, public sources and questionnaires, then selects material issues for the industry.
  3. Each issue is scored, weighted by importance, and added up under environmental, social and governance pillars to get the overall score, which is converted into a grade or category.
  4. Analysis of divergence: providers choose different issues, weights and data sources, and some rate relative to peers while others measure absolute risk.
  5. They also treat missing data differently, for example by estimating or by penalising.
  6. Conclusion: because methods differ, ratings are not directly comparable. A board should read the methodology and not rely on a single rating.

Answer: An ESG rating is built through data collection, material issue selection, scoring, weighting and aggregation. Providers differ in issues, weights, data and relative or absolute approach, so the same company can get different ratings. Compare the methodology before using any rating.

Example 2

Aarav Steels Ltd., a listed company, finds that one provider gives it a low-risk rating while another gives a medium-risk rating. The board asks you, as Company Secretary, how to respond. Advise.

Show the solution
  1. Identify the issue: two providers, two results. This is common because methodologies differ.
  2. Obtain each provider's methodology, the data used and the weights for the steel industry.
  3. Check the data for errors or missing disclosures, for example emissions or safety data, and correct them through proper channels, including BRSR disclosures.
  4. Identify the weak areas that drive the medium-risk result and set targets and board oversight for them.
  5. Avoid claims that overstate the rating in communications, and state which provider and date any rating refers to.
  6. Conclusion: do not choose the better result for marketing. Use both as inputs for improvement and improve disclosure quality.

Answer: The difference is normal because providers use different methods. Review the methodologies, verify and improve the data, address the weak areas under board oversight, and describe ratings accurately without selective use.

Exam tips

  • Answer in the order: definition, build steps, providers, uses, limits, conclusion. It matches how marks are given.
  • Use the scale direction correctly for each provider and name the provider whenever you quote a grade.
  • Link the topic to BRSR and SEBI's regulation of rating providers to show current Indian knowledge.
  • For case questions, apply the facts: name the company's industry and the material issues that matter for it.
  • Never quote numbers for a provider's weights unless the question gives them.

Practice questions from Sustainability Audit, ESG Rating and Emerging Mandates from Government and Regulators

ESG Ratings and Rating Providers in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

ESG Ratings and Rating Providers: frequently asked questions

What is an ESG rating and how is it calculated?

It is an independent assessment of how well a company manages material ESG risks. Providers gather data, choose industry-specific issues, score and weight them, and add them into an overall score that is converted to a grade or category. The exact formula differs by provider.

What is the difference between an ESG rating and an ESG score?

A score is the number calculated from the weighted assessment. A rating is the grade or category assigned from that score, such as AAA to CCC. Many providers and users use the terms loosely, so state your meaning in the answer.

Which ESG rating agencies operate in India?

Global providers such as MSCI, Sustainalytics, S&P Global and ISS ESG cover Indian companies. Indian agencies such as CRISIL, ICRA, CARE, Stakeholders Empowerment Services and IiAS have also offered ESG ratings or scores. ESG rating providers in India are regulated by SEBI.

What are the main limitations of ESG ratings?

Ratings from different providers often differ because of method and weights. They rely on disclosed data that may be incomplete, involve judgement, can lag events, and may favour large companies with more disclosure. Use them as one input only.