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Important facts
- What does ESG mean?
- ESG stands for Environment, Social and Governance - three criteria by which companies are assessed for their sustainability performance.
- What is the purpose of ESG ratings?
- ESG ratings help investors to identify sustainable companies and make informed investment decisions.
- Where does the valuation data come from?
- The valuation data comes from annual reports, sustainability reports and publicly accessible sources.
- Which rating agencies are there?
- Well-known rating agencies include MSCI, Sustainalytics, S&P Global and ISS ESG.
- How are ratings presented?
- Ratings are shown as a categorical classification (e.g. AAA to CCC) or as a numerical score (e.g. 0-100).
- Are ESG ratings standardized?
- A uniform standard does not yet exist, which is why different agencies can rate the same company differently.
- What are the benefits of a good rating for companies?
- A good rating is worthwhile for companies, as it facilitates access to sustainable capital and strengthens their public image.
Abstract
ESG stands for environment, social and governance. ESG investments are investment strategies that take these three factors into account alongside financial returns. The aim is to channel capital specifically into companies that operate responsibly and are stable in the long term.
In order to make the sustainability performance of companies comparable, independent rating agencies such as MSCI or Sustainalytics award ESG ratings and scores. These are based on company reports, public data and proprietary analysis models - and help investors to make well-founded, value-oriented investment decisions.
ESG investing offers real opportunities: risk reduction, better long-term performance and a positive social impact. At the same time, there are challenges such as the lack of standardization of ratings and the risk of greenwashing. If you understand the basic principles, you can better classify both - which is exactly what this article is about.
Definition & importance of ESG investments
ESG investments are forms of investment that are geared towards sustainability and take three key factors into account: Environment, Social and Governance. The aim is to reconcile ethical aspects and financial returns.
Companies that are eligible for ESG investments must be convincing in all three areas:
- Environment: sustainable resource management, reduction of CO₂ emissions and responsible treatment of nature
- Social: fair working conditions, human rights and social responsibility
- Governance: transparent corporate management, ethical behavior and clear compliance structures
For investors, this means that their capital flows specifically into companies that are not only economically stable, but also actively contribute to risk mitigation, for example by dealing with regulatory or reputational risks at an early stage.
The growing trend towards sustainable investments reflects the increasing awareness of environmental and social issues in the financial sector. More and more investors are recognizing the added value of a holistic view of investments that takes these aspects into account. It is therefore crucial for investors of all kinds, whether institutional investors or private individuals, to design their portfolios with environmental protection, social responsibility and good corporate governance in mind. Overall, ESG investments and corresponding investment strategies offer an opportunity for investors to invest their capital profitably and make a positive contribution to society at the same time.
The trend is clear: more and more institutional investors and private individuals are integrating ESG criteria into their portfolio strategy - not despite, but because of the long-term return prospects.
Background and origin
ESG investments have become considerably more important in recent years. This form of investment is due to the growing awareness of sustainability issues. In the past, the focus of investments was mainly on financial returns, without much consideration of environmental or social impact. Nowadays, this perspective has changed as more and more people recognize the importance of responsible investing.
The history of ESG investing dates back to the 1960s, when more and more companies began to integrate ethical and social aspects into their business activities. This illustrates a trend towards a more holistic approach to investment decisions. More and more investors are recognizing the long-term value of sustainable investing and are demanding transparency from companies in terms of environmental impact and social responsibility.
Initiatives such as the UN Principles for Responsible Investment (PRI)(on the principles), the Sustainable Development Goals(SDGs) and the Paris Agreement(on the Paris Agreement) make it clear that ESG factors are not only ethically correct, but can also have a positive impact on long-term returns. These sustainable developments have meant that ESG criteria are now a fundamental part of the global financial system.
How ESG investing works
ESG investing, also known as sustainable investing, is an investment strategy that combines financial returns with environmental and social responsibility. Unlike traditional investment strategies, the focus is not exclusively on returns: companies are also evaluated and selected based on their performance in three key areas.
- Environment: How does the company use natural resources? This includes the ecological footprint, the use of renewable energies, the reduction of CO₂ emissions and the responsible use of water and raw materials.
- Social: How does the company treat its employees, suppliers and society? Among other things, working conditions, equal pay, human rights and diversity in the workplace are assessed.
- Governance: How is the company managed and controlled? Transparency, the prevention of corruption, the independence of the Supervisory Board and ethical behavior play a central role here.
In short, not every profitable company fulfills ESG criteria, and this is the crucial difference to traditional stock selection.
There are various approaches to practical implementation. Many investors use so-called negative screening strategies, in which certain sectors such as weapons, tobacco or coal are generally excluded. Positive screening, on the other hand, involves specifically selecting the companies that perform best in the ESG areas within their sector, the so-called best-in-class approach. There is also the active ownership approach: investors use their voting rights as shareholders to actively encourage companies to act more sustainably.
How can you invest specifically?
Investors have various options for integrating ESG criteria into their strategy:
- ESG ETFs: Passive funds that track a sustainable index - cost-effective, transparent and broadly diversified. Particularly suitable for beginners who want to invest in sustainability in an uncomplicated way.
- ESG funds: Actively managed funds in which experienced fund managers specifically select sustainable companies and regularly adjust the portfolio. Often higher costs, but potentially more precise ESG focus.
- Individual stocks: The individual selection of companies based on their own ESG criteria - requires more time, knowledge and an independent analysis of the available ratings.
- Green bonds: Bonds whose proceeds are used exclusively for sustainable projects such as renewable energies or climate-friendly infrastructure. Particularly popular with investors with a clear focus on measurable environmental impact.
- Impact investing: A particularly targeted form of ESG investing in which investors consciously invest in projects or companies that achieve a concrete, measurable positive social or environmental impact.
Important: Not every product that markets itself as "sustainable" or "ESG-compliant" delivers what it promises. A critical look at the underlying criteria and ratings is therefore essential.
These diverse options allow investors to flexibly adapt ESG investing to their personal preferences, values and risk profile, whether as a simple entry via a broadly diversified ETF or as a targeted individual investment in sustainable pioneers in their sector.
ESG ratings and scores - what are they?
ESG ratings and ESG scores are tools that evaluate and compare companies in terms of their environmental, social and governance performance. They are based on a variety of data sources, including annual reports, sustainability reports, media reports and direct company information. The aim is to give investors a reliable indication of how sustainably and responsibly a company actually operates.
The difference between rating and score is important here:
- ESG rating: A categorical classification, similar to credit ratings. MSCI, for example, uses a scale from AAA (best rating) to CCC (worst rating).
- ESG score: A numerical value, usually on a scale of 0 to 100. Sustainalytics, for example, rates companies based on their risk exposure - the lower the score, the lower the ESG risk.
What do ratings actually do?
A good ESG rating has far-reaching implications, both for investors and for companies themselves:
- For investors: quick comparability of companies within a sector, identification of sustainability risks and basis for ESG-compliant portfolio decisions
- For companies: Improved image among investors and stakeholders, easier access to sustainable capital and a clear incentive to continuously improve their own ESG performance
Independent rating agencies regularly carry out these assessments, making the sustainability performance of companies transparent and comparable for investors.
Important to know: Different rating agencies can rate the same company differently, as there is currently no uniform standard. A company that receives an A rating from MSCI may also have a medium risk level from Sustainalytics. Investors should therefore never rely on just one source.
How does the rating work?
The basis of every ESG rating is systematic data collection and analysis. Rating agencies collect information from various sources and consolidate it into an overall rating. In simplified terms, the process can be divided into four steps:
- Data collection: The agencies collect data from annual reports, sustainability reports, media reports, NGO publications and sometimes also from direct company questionnaires.
- Categorization: The collected data is assigned to the three ESG areas and evaluated based on industry-specific criteria - for example, an energy company is examined more strictly for environmental aspects than a software company.
- Weighting: Each category and each criterion is weighted according to its relevance to the overall picture. In some cases, the agencies differ considerably from one another here.
- Scoring: An overall score or rating is calculated from the weighted individual assessments, which reflects the ESG performance of the company as a whole.
The better a company performs in the areas of environmental protection, social responsibility and corporate governance, the higher its score and the more attractive it becomes for sustainable investors.
ESG rating in practice: the example of Siemens
To understand what an ESG rating looks like in practice, it is worth taking a look at Siemens, one of the most analyzed German companies in the ESG sector.
For the 2025 financial year, Siemens received the top rating of AAA from MSCI, the highest rating on a scale from AAA to CCC. MSCI assesses the extent to which a company is exposed to industry-specific ESG risks and how well it manages them.
Sustainalytics, on the other hand, focuses on the level of risk: the model assesses the extent to which a company is exposed to ESG risks and how well it manages them, with exposure and management being assessed separately. Siemens is classified as a company with strong ESG risk management.
What does this example show? Both agencies come to a positive assessment but with a different perspective: MSCI rates the overall performance with a grade, Sustainalytics quantifies the remaining residual risk. For investors, this means that only a comparison of several sources provides a complete picture.
The most common evaluation criteria at a glance:
What exactly is the assessment based on?
CO₂ emissions, energy consumption, water consumption, waste management, biodiversity
Occupational safety, equal pay, supply chain standards, community projects, employee satisfaction
Management Board remuneration, independence of the Supervisory Board, anti-corruption measures, shareholder rights, transparency of reporting
A comparison of the major rating agencies
Three providers dominate the ESG rating market: MSCI, Sustainalytics and S&P Global. Each pursues its own approach, which means that the same company can be rated very differently depending on the agency.
MSCI uses a rules-based methodology and rates companies on a scale from AAA to CCC, relative to their industry peers. It assesses how well a company manages sector-specific ESG risks compared to its peers.
Sustainalytics, on the other hand, measures the absolute ESG risk: the score indicates the extent to which the economic value of a company is jeopardized by ESG factors. Companies are divided into five risk levels: from "Negligible" (0-10) to "Severe" (40+).
S&P Global rates a company's ESG performance relative to its industry peers on a scale of 1 to 100, combining elements of performance measurement and risk assessment.
The central problem: According to MIT researchers, the correlation between ESG ratings from different agencies is only 0.61 on average - in comparison, the correlation between Moody's and S&P for credit ratings is 0.99. This shows that ESG ratings are far less consistent than traditional financial ratings.
For investors, this means that passive investors and index-tracking funds often follow MSCI, while active investors prefer Sustainalytics' absolute risk model. Many institutional investors use both agencies on a complementary basis.
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The limits of the system
Despite its usefulness, ESG assessment has some structural weaknesses that investors should be aware of:
- Lack of standardization: There is no uniform method for calculating ESG scores. Each agency weights criteria differently, which can lead to sometimes contradictory results.
- Data availability: Not all companies - especially smaller or unlisted companies - publish sufficient ESG-relevant data, which limits the quality of the valuation.
- Time lag: Ratings are often based on historical data and may not immediately reflect current developments in the company.
- Subjectivity: The selection and weighting of the criteria ultimately remains a decision made by the respective agency - and is therefore never completely objective.
ESG ratings are a valuable guidance tool, but not an infallible judgment. Investors should consider them as one of several components of their investment decision - not as the sole basis.
How do you improve your score?
Improving the ESG score is not a one-off project, but a continuous process that requires sustainability to be genuinely anchored in the corporate strategy. The first and most important step is transparency: companies that report openly and regularly on their sustainability measures - for example through structured sustainability reports or the disclosure of CO₂ emissions - are generally rated better by rating agencies than those that communicate little.
Transparency is the basic prerequisite. The rule here is: if you don't report, you won't be rated.
At the same time, the concrete implementation of sustainable business practices is also important. This means not only reducing the company's own ecological footprint, but also taking measures in the social sphere, such as actively promoting diversity, improving working conditions along the entire supply chain or introducing clear compliance and anti-corruption guidelines. Such measures have a direct impact on all three ESG dimensions and strengthen the overall rating in the long term.
An often underestimated factor is the involvement of stakeholders. Companies that actively seek dialog with employees, customers, suppliers and investors and incorporate their feedback into their decision-making processes signal to rating agencies that they have a living sustainability culture and not just a superficial external image.
Ultimately, an improved ESG score is not the goal, but the result - namely when sustainability is truly anchored at the core of the company.
Risks and opportunities of sustainable investments
ESG investments offer real opportunities, but if you want to make informed investments, you should also be aware of the risks. Both are part of an honest assessment.
Risks
One of the biggest challenges is that it is difficult to measure: it is often impossible to clearly determine the actual impact that ESG factors have on a company's financial performance. There is also the risk of greenwashing, i.e. deliberately presenting oneself to the outside world as sustainable without actually reflecting this in business practices. Regulatory changes can also disproportionately affect certain sectors or regions and thus influence the performance of ESG-compliant portfolios.
In short: ESG does not protect against market risks and a good rating is no guarantee of financial stability.
Opportunities
On the other hand, there are strong arguments in favor of ESG investments. Companies with a credible sustainability strategy are often more resilient to external shocks, be it climate change, regulatory pressure or social change. In the long term, this can lead to a more stable performance. In addition, ESG investments enable investors to actively deploy their capital for positive social change, an aspect that is playing an equally important role to returns for more and more investors.
ESG investing does not mean foregoing returns, but rather combining returns and responsibility.
Advantages and disadvantages of ESG investments
Advantages:
- Positive impact on society and the environment: One of the biggest benefits is the opportunity to promote sustainable change and have a positive impact on environmental and social standards. Through targeted investments, investors can help companies to act more responsibly and make a long-term commitment to sustainability.
- Risk reduction: Another advantage of sustainable investments is risk reduction. By incorporating environmental, social and governance factors into investment decisions, investors can reduce financial risks such as reputational damage or legal problems.
- Improving financial performance: It has been shown that companies that meet the criteria are generally more successful. They have fewer risks and pursue a long-term perspective.
- Increasing demand and social acceptance: The public's growing interest in sustainability and social responsibility is increasing the popularity of sustainable investments. This can lead to higher capital inflows and better returns for these companies.
Disadvantages:
- Evaluation challenges: As there are no standardized methods for evaluating environmental social governance factors, it can be difficult to objectively compare companies and find objective criteria for evaluating sustainability.
- Greenwashing: There is a risk of so-called "greenwashing", where companies disguise their image as sustainable even though they do not actually act accordingly.
- Higher costs: Some sustainable funds have higher fees than conventional funds, as they are often actively managed and require additional analysis and due diligence.
- Transparency gaps: Not all companies communicate in detail about their ESG measures, which makes it difficult to obtain an accurate assessment of their actual performance in this area. For investors who value this openness, ELTIFs (European Long-Term Investment Funds) are recommended: These have a focus on impact (impact investing) and strive to make this traceable.
- Lower returns: In addition, the criteria may sometimes conflict with an investor's financial objectives. Investors may have to compromise on expected returns or exclude certain sectors in order to remain true to their ethical principles.
Conclusion
ESG investments are no longer a niche topic; they are an integral part of modern investment strategies. If you want to combine returns and responsibility, ESG criteria provide a valuable framework for making targeted investments in companies that are stable, transparent and sustainable in the long term.
At the same time, ESG investing requires a critical basic understanding. Ratings are orientation aids, not infallible judgments. Greenwashing exists, as does a lack of standardization. Those who are aware of these limitations can take them into account and ultimately make better decisions.
If you want to start ESG investing now, you should first clearly define your own values and return targets, familiarize yourself with the common rating agencies and make an uncomplicated start with a broadly diversified ESG ETF.
ESG is not a sacrifice of performance, it is a decision about how and in what you invest. And that is ultimately a question that every investor has to answer for themselves.
Frequently asked questions
ESG ratings assess the sustainability performance of companies in the areas of environmental, social and governance. To do this, rating agencies analyze company data, reports and public information to assign an overall grade or score. These ratings help investors to assess the ethical and sustainable practices of companies and make informed investment decisions.
ESG scores are calculated by collecting and analyzing data from company reports, public sources and media coverage. This data is divided into three categories - environmental, social and governance - with different criteria weighted depending on the industry and specific rating agency. The scores are determined by point systems and benchmarking and then validated. Finally, the results are published in a comprehensive report detailing the company's performance.
Sustainability ratings are important for investors as they provide insights into companies' sustainability and risk management practices. They help to identify potential risks from environmental, social and governance issues, leading to better risk mitigation. They also promote sustainable investment strategies by enabling investors to select companies that align with their ethical values. In light of increasing regulatory requirements, ESG ratings also support compliance with necessary transparency standards. Overall, they contribute to long-term value creation and stability in the portfolio.
Companies with high ESG ratings benefit from several advantages, including improved access to capital and more attractive financing conditions, as they are particularly appealing to sustainable investors. They also strengthen their reputation and brand value, which increases the trust of customers and stakeholders. These companies can differentiate themselves from competitors and are often better able to identify and manage risks. In addition, strong ESG practices lead to higher employee satisfaction and retention and contribute to overall long-term stability and competitiveness.
ESG investments entail several risks. The availability and quality of sustainable data often varies, which can lead to inaccurate analyses. Different assessment methods used by rating agencies also make comparability difficult. ESG investments are not free from general market risks and fluctuations. Regulatory changes can also have an impact on the environment. Another problem is greenwashing, where companies exaggerate their sustainability performance.
There are several rating agencies, including household names such as Sustainalytics, MSCI ESG Research, FTSE Russell, Bloomberg ESG Data, Refinitiv, RobecoSAM and ISS ESG. Each agency uses different methodologies and criteria in their assessments, which can lead to slightly different results. While this diversity offers investors a wide choice, it also presents challenges in terms of comparability and interpretation of the ratings. It is therefore important to understand the respective rating approaches of the different agencies in order to make informed investment decisions.
Ratings are usually updated at least once a year, although the frequency can vary depending on the rating agency and industry. Some agencies also offer continuous monitoring to adjust ratings immediately upon relevant events such as new reports or changes in corporate governance. In industries with rapidly changing practices, more frequent updating may be required. Updates also depend on the availability of new data that is incorporated into the ratings. Investors should be aware that a company's ratings can change quickly based on current developments and information.
Companies can actively influence their ESG scores by developing sustainable corporate strategies that include environmental, social and governance goals. Transparent reporting on progress, dialog with stakeholders and raising employee awareness are also important steps towards improving performance. In addition, identified weaknesses should be proactively addressed, for example by investing in environmentally friendly technologies or introducing compliance programs. By taking these measures, companies can not only improve their ratings, but also create long-term value for their stakeholders.
The main criticisms of ratings are their subjectivity and inconsistency, as different rating agencies can deliver different results for the same company. A lack of transparency in the rating methods makes it difficult for investors to understand the results. There is also a risk of greenwashing, where companies exaggerate their ESG performance. Furthermore, ratings are sometimes unable to react quickly enough to current changes. An overemphasis on quantitative data can neglect important qualitative factors, resulting in an incomplete picture of ESG performance. Overall, these challenges require a critical understanding of ratings in order to make informed sustainable investment decisions.
Investors can integrate ratings into their decisions by considering them as part of their due diligence and analyzing the ESG performance of potential investments. Regular assessments of ESG ratings in one's own portfolio and the targeted replacement of investments with low ratings are also useful. Investors can also use special sustainable funds or ETFs to invest in sustainable companies. A long-term approach and active dialog with companies to improve their practices strengthen the integration of ESG criteria. Investors should also be informed about current trends and regulatory developments in order to continuously adapt their strategies.
The main difference between ESG ratings and traditional financial ratings lies in their focus: while financial ratings evaluate a company's economic performance and stability, ESG ratings focus on its environmental, social and governance practices. Financial ratings are mainly based on quantitative metrics such as revenue and profit, while ESG ratings take into account both quantitative and qualitative criteria that have a long-term impact on company performance. In addition, ratings are based on ethical and sustainable investment trends, while traditional ratings primarily focus on short-term financial health. Finally, they reflect different stakeholder expectations, as ESG ratings also focus on social and environmental responsibility.
ESG ratings are currently not standardized, as different rating agencies use different methodologies, criteria and weightings, which can lead to inconsistent results. The terms and criteria are often not clearly defined, which makes comparability difficult. However, there are efforts towards standardization, for example through initiatives such as the Global Reporting Initiative (GRI) and the Sustainability Accounting Standards Board (SASB), as well as regulatory developments. Investors should be aware of the variability and understand the agencies' respective methodologies in order to make informed decisions.
The ratings are forward-looking for the financial sector, as they promote the growing interest in sustainable investments and the integration of environmental and social criteria into investment strategies. They enable a more comprehensive risk assessment that goes beyond traditional financial metrics and help companies to implement responsible practices. Regulatory developments are increasingly demanding transparency with regard to ESG factors, which makes the topic even more relevant. ESG ratings are also driving the development of new sustainable financial products such as funds and ETFs. Overall, the consideration of ESG criteria is recognized as crucial for the long-term success and stability of companies and portfolios.
Alexander Hilmar
LinkedInESG-Compliance Experte · lawcode GmbH
Alexander Hilmar berät Unternehmen bei der Umsetzung von ESG-Compliance, nachhaltiger Berichterstattung und begleitet die Implementierung digitaler Lösungen für rechtssichere Lieferketten. Seine Fachbeiträge auf dem lawcode Blog verbinden regulatorische Tiefe mit praxisnahen Handlungsempfehlungen.
