ESG investing has gone from niche to mainstream and back to contested — all within a decade. Proponents argue it delivers competitive returns while aligning capital with positive outcomes. Critics argue it underperforms, is riddled with greenwashing, and imposes ideological constraints on portfolio construction.
The evidence is more nuanced than either camp suggests. This guide cuts through the noise to give international investors a clear-eyed view of what ESG is, how it performs, what to watch out for, and how to think about it in practice.
What Is ESG?
ESG stands for Environmental, Social, and Governance — three dimensions along which companies and investments can be assessed beyond traditional financial metrics:
Environmental: Carbon emissions, climate risk, resource use, pollution, biodiversity impact, supply chain environmental impact
Social: Labour practices, employee wellbeing, supply chain labour conditions, product safety, community relations, data privacy
Governance: Board structure and independence, executive pay, shareholder rights, anti-corruption policies, capital allocation discipline, accounting quality
ESG investing uses these factors either to exclude certain investments, to prefer higher-scoring companies, or to integrate ESG factors into financial analysis on the basis that they represent relevant risks and opportunities.
The Performance Question: Does ESG Outperform or Underperform?
This is the question that generates more heat than light. The honest answer is: it depends on the time period and the specific implementation.
2015–2020: ESG appeared to outperform
During this period, ESG portfolios — which tend to underweight fossil fuels, utilities, and resource extraction, and overweight technology and healthcare — benefited from technology outperformance and the underperformance of energy and mining. It was easy to claim ESG outperformed, but much of the apparent alpha was actually a sector bet on technology.
2021–2022: ESG significantly underperformed
The energy price spike following Russia's invasion of Ukraine in February 2022 sent oil and gas stocks surging. ESG portfolios, underweight in energy, significantly underperformed conventional benchmarks during this period. Critics used this period to declare ESG "dead". The reversal exposed how much prior ESG outperformance had been sector-driven rather than fundamental.
2023–2026: Mixed performance
Performance has been more mixed since 2023. Energy sector returns have moderated. Technology has resumed outperformance in AI-driven stocks, benefiting ESG portfolios again. The net picture is that ESG performance versus conventional benchmarks is driven largely by sector rotation rather than any systematic ESG-specific premium.
The academic evidence:
A large body of academic research on ESG finds:
- ESG integration (using ESG data as one input among many) does not systematically reduce returns and may marginally improve risk-adjusted returns by identifying material risks
- ESG exclusion (removing certain sectors) underperforms when excluded sectors outperform — which is unpredictable
- The evidence for a systematic ESG premium (that "good" companies consistently outperform "bad" ones) is weak and contested
The practical conclusion for investors:
Do not expect ESG to systematically outperform conventional investing. The evidence does not support that expectation. Choose ESG for alignment with your values if that matters to you, not because you expect it to generate alpha.
Greenwashing: How to Spot It
Greenwashing is the practice of marketing a fund or product as environmentally or socially responsible when its actual credentials are limited.
Greenwashing scandals that have damaged industry credibility include:
DWS Group: Deutsche Bank's asset management arm faced investigation in Germany and the US after a whistleblower alleged that DWS had overstated the proportion of assets managed under ESG criteria. In 2023 DWS settled with the US SEC for $19 million (then the largest ESG-related penalty the SEC had imposed on an investment adviser); it separately reached a settlement with German prosecutors in 2025.
HSBC Asset Management (2022): Banned by the UK's Advertising Standards Authority from running claims that it was "investing in a net zero future" — the ASA found the claim was misleading given HSBC's broader financing activities.
Multiple fund name changes: A large number of conventional funds were renamed to add "sustainable", "responsible", or "ESG" without material changes to holdings.
How to spot greenwashing:
Check the actual holdings. Many "sustainable" funds still hold fossil fuel companies, defence contractors, and other assets that ESG investors typically intend to exclude. The SFDR classification (below) helps but is not foolproof.
Look at the carbon footprint data. Fund providers are increasingly required to disclose the weighted average carbon intensity of their portfolios. Compare this with a conventional benchmark equivalent.
Check third-party ESG ratings. MSCI, Sustainalytics, and ISS all provide ESG ratings for funds. These ratings do not always agree (different methodologies lead to different conclusions), but significant divergence between self-described ESG credentials and third-party ratings is a warning sign.
Read the SFDR classification (if an EU/Dublin-domiciled fund).
Question the fee. ESG funds frequently charge higher fees than conventional equivalents. If the ESG screening process is not genuinely adding rigour, there is no justification for the premium.
The Different ESG Approaches
ESG is not one thing. There are four meaningfully different approaches:
1. Exclusion (Negative Screening)
The simplest approach: remove companies in certain industries from the investment universe. Common exclusions include tobacco, weapons, adult entertainment, gambling, fossil fuels.
Exclusion is clear and transparent. You know what you are not holding. The trade-off is sector concentration — an exclusion portfolio may be significantly overweight in certain sectors relative to the market.
Exclusion portfolios are not necessarily low-carbon — a portfolio that excludes tobacco but retains oil majors has made a moral choice but not necessarily a climate one.
2. ESG Integration
Rather than excluding sectors, integration applies ESG data as an additional input into financial analysis. The thesis is that ESG factors represent material financial risks (a company with poor governance is a fraud risk; a company with high carbon exposure faces regulatory risk) and should therefore be considered in valuation.
Integration does not necessarily change the composition of the portfolio dramatically. It is designed to identify within-sector leaders and laggards, not to exclude entire industries.
3. Best-in-Class (Positive Screening)
Best-in-class retains exposure across all sectors but tilts towards the highest ESG-rated companies within each sector. An oil company with robust emissions reporting and strong governance ranks higher than one without.
This approach preserves diversification while rewarding better corporate behaviour. It is controversial among committed ESG investors who argue that "best-in-class oil" is still oil.
4. Impact Investing
Impact investing specifically targets investments that generate measurable, intentional positive outcomes alongside financial return. Examples include green bonds (financing renewable energy projects), social housing bonds, microfinance institutions, and private equity backing in clean technology.
Impact investing is the most explicitly values-aligned approach, but access is typically through private markets rather than public funds, meaning higher minimum investments and lower liquidity.
EU SFDR: Article 6, 8, and 9 Explained
The EU Sustainable Finance Disclosure Regulation (SFDR) requires fund managers distributing funds to EU investors to classify their funds under three articles:
Article 6: The fund does not promote environmental or social characteristics and does not have a sustainable investment objective. It may consider ESG risks as financial risks (material risk management) without making ESG claims. Most conventional funds fall here.
Article 8 ("Light Green"): The fund promotes environmental and/or social characteristics, without having a sustainable investment as its core objective. This is the broadest category and covers a wide range of products — from deeply integrated ESG approaches to products that do very little beyond basic exclusions. Article 8 is where much greenwashing has occurred, because the standard is relatively low.
Article 9 ("Dark Green"): The fund has a sustainable investment objective — its goal is specifically to invest in sustainable activities and generate positive environmental or social outcomes. Article 9 funds must measure and report on sustainability outcomes. These are the most stringent ESG products.
Practical guidance:
- Do not assume an Article 8 fund is deeply ESG — it is a heterogeneous category
- Article 9 funds are more rigorous but may also be more concentrated (fewer eligible investments)
- SFDR applies to EU-domiciled funds and UK-marketed funds under UK SFDR equivalent frameworks — check which regime applies to funds you are considering
The Best ESG ETFs for International Investors
(Note: we list fund families rather than specific products, as prices, availability, and fund names change. Always verify current details directly with providers.)
Broad global ESG ETFs:
- iShares MSCI World ESG Screened ETF (BlackRock) — tracks MSCI World with exclusions for weapons, tobacco, thermal coal, controversial industries. Low cost. Article 8.
- Vanguard ESG Global All Cap UCITS ETF — broad global equity with ESG exclusions; one of the lower-cost options in the space
- SPDR MSCI World ESG Leaders UCITS ETF — best-in-class approach within sectors
- UBS MSCI World Socially Responsible UCITS ETF — stricter ESG criteria than many peers
Thematic/climate-specific ETFs:
- iShares Global Clean Energy UCITS ETF — concentrated clean energy exposure; high volatility
- Lyxor MSCI Global Climate Change ESG Filtered UCITS ETF — climate-tilted with ESG screening
- PIMCO Climate Bond UCITS ETF — green bonds; Article 9
Impact/Article 9:
- Triodos Global Equities Impact Fund — actively managed; strict positive screening; higher fee
- Mirova Global Sustainable Equity Fund — impact-oriented active management
For a core ESG allocation:
A combination of a broad global ESG ETF (as core equity) and a green bond or sustainable bond ETF (as fixed income) is a simple, low-cost starting point. Total cost should be under 0.30% per annum for this core.
Sustainable Bonds: Green, Social, and Sustainability
The fixed income market has developed a substantial sustainable finance segment:
Green bonds: Proceeds designated specifically for environmental projects (renewable energy, clean transport, sustainable water). The issuer provides a second-party opinion and annual use-of-proceeds reporting. Government issuers (UK sovereign green bond), supranationals (European Investment Bank), and corporates all issue green bonds.
Social bonds: Proceeds for social benefit projects — affordable housing, healthcare access, education. Grew significantly during COVID-19 as governments raised social bonds to fund healthcare responses.
Sustainability bonds: Combines green and social use of proceeds.
Sustainability-linked bonds (SLBs): Different from the above — these are not use-of-proceeds instruments. Instead, the coupon adjusts (typically rises) if the issuer fails to meet specified sustainability KPIs (e.g., emissions reduction targets). This structure has faced criticism for weak KPIs and self-set targets.
For an investor with fixed income in a portfolio, replacing a portion of conventional bond exposure with green bond equivalents from the same issuers (e.g., UK gilts vs UK sovereign green gilts) provides ESG alignment with minimal financial difference.
What ESG Means for a Portfolio Practically
For most internationally mobile investors adding an ESG dimension to their portfolio, the practical steps are:
Clarify your priority. Are you primarily concerned with avoiding certain industries (exclusion)? With carbon footprint? With governance quality? Different priorities lead to different fund choices.
Replace core equity with an ESG-screened equivalent. A MSCI World ESG Screened ETF is a direct substitute for an MSCI World ETF in portfolio terms — broadly similar sector exposure (with some exclusions), similar costs (slightly higher), similar liquidity.
Do not sacrifice diversification. Very narrow ESG or thematic ETFs (e.g., pure clean energy ETFs) carry significant concentration risk. Use these as satellite positions around a broad core, not as a substitute for core global equity.
Check what you are actually holding. Use a portfolio X-ray tool (Morningstar Portfolio Manager, for example) to see the actual underlying companies and their ESG ratings. You may be surprised by what is in an "ESG" fund.
Ignore the marketing. Virtually every fund manager now has an "ESG story". Judge by actual holdings, methodology, and cost — not the marketing brochure.
How Global Investments Can Help
We help clients integrate ESG considerations into their portfolios in a way that is consistent with their financial objectives, not at the expense of them. We access ESG research from independent sources rather than relying on product provider marketing, and we are transparent about where the evidence is strong and where it is contested.
Contact us to discuss how your investment approach can reflect your values without compromising your financial plan.
Investment values can fall as well as rise. ESG fund performance has varied and is not guaranteed to meet expectations. This article is for informational purposes only and does not constitute regulated financial advice. ESG ratings are the product of specific methodologies that may not align with your personal definition of responsible investing.
This article is for general information only and does not constitute financial, legal or tax advice. Rules, prices and regulations change; verify current requirements with a qualified adviser before acting.