Sustainable investing does not guarantee better returns and does not remove market risk. Anyone claiming otherwise is selling something. Capital is at risk in every approach described here.
The words mean different things
Most confusion about sustainable investing is vocabulary. Four labels get used interchangeably and describe genuinely different strategies.
- Exclusion (negative screening)
- Simply not holding certain sectors — tobacco, weapons, thermal coal. Easy to verify, and the weakest form of influence.
- ESG integration
- Environmental, social and governance factors treated as financial risk factors alongside everything else. The fund may still hold a company you dislike, if the risk is priced.
- Best-in-class
- Holding the better performers within each sector rather than excluding the sector. You may still own an oil company — the one behaving best.
- Impact investing
- Capital deployed to produce a measurable outcome, with the outcome reported. The most demanding, and the smallest category.
Read the holdings, not the name
A fund can carry a sustainability label and hold companies that would surprise you. The holdings list is public. Five minutes reading it beats any amount of brochure.
What the evidence supports
| Claim | What the evidence actually shows |
|---|---|
| "ESG funds outperform" | Mixed and period-dependent. Much apparent outperformance came from sector tilts, particularly away from energy and towards technology. |
| "ESG reduces risk" | Better supported. Governance quality in particular correlates with fewer catastrophic corporate failures. |
| "You sacrifice returns" | Not well supported either. Broad sustainable indices have tracked conventional ones reasonably closely over long periods. |
| "Divesting changes company behaviour" | Weak on its own. Selling transfers the shares to a less concerned owner; engagement and voting have stronger evidence behind them. |
| "Ratings are objective" | No. Different providers score the same company very differently, because they measure different things. |
The honest summary
Sustainable investing is best understood as aligning a portfolio with your values while managing a real category of risk. Treating it as a return-enhancement strategy is where disappointment starts.
Spotting greenwashing
- 1Read the top twenty holdings. If they are the same as a conventional index, the strategy is doing very little.
- 2Check the exclusion list. A specific, published list is a commitment; a vague statement of principles is not.
- 3Look for engagement and voting records. A manager who never votes against management is not engaging.
- 4Compare the fee against a conventional equivalent. A large premium needs to buy something identifiable.
- 5Check which ratings provider is cited, and whether the manager would use a different one if it scored better.
- 6Ask what would cause them to sell a holding. If there is no answer, there is no policy.
Building a portfolio that fits
Decide what you actually care about
Climate, labour practice, governance, weapons. "Everything" is not a specification and produces a portfolio nobody is happy with.
Choose the mechanism
Exclusion for clear lines you will not cross; integration for risk management; impact where you want measurable outcomes.
Keep the diversification
Every exclusion narrows the universe. Excluding a great deal concentrates the portfolio, and concentration is a real risk.
Set the cost ceiling
Decide the maximum premium you will pay over a conventional equivalent, before you look at products.
Review annually
Holdings drift, mandates change, and a fund that fitted three years ago may not now.
Documents you may also need
Sustainable Investing: Myths vs Reality
Six claims made about sustainable investing, examined one at a time, with what the evidence supports and what it does not.
GuidesAlternative Assets: Beyond Equities
Private equity, venture, property, infrastructure and private credit — what each actually is, what you give up to hold it, and who they suit.
InsightsMarket Forecast & Trends
Our standing view on rates, currencies, credit and equities — what drives each, what we watch, and what it means for the decisions in front of you.
This document was last updated on 1 August 2026. We publish the current version here at all times; superseded versions are available on request.
If anything on this page is unclear, write to us and we will explain it.