Greenwashing is the risk that a fund does not own what its name says it owns. It is the biggest risk an impact investor carries because it defeats the purpose of the allocation while leaving every visible signal intact. Returns, tickers and quarterly statements all look normal. Nothing in a fund's reporting announces that the gap exists. The exposure shows up in three places.
You may be paying for differentiation you have not checked. Your portfolio may not produce the real-world outcome you believed you were funding. And the label itself can disappear without a single holding changing — as it has for roughly a third of labeled U.S. sustainable funds since 2023, with no regulation forcing the change. Each of these is checkable at the level of what you own. None of them is visible in a fund name.
The fee question is not how much a sustainable fund charges. It is what the charge buys. A fund that screens a broad index and keeps most of it has changed your holdings very little, whatever it costs. You can measure that yourself in about five minutes.
Two design choices explain the resemblance. The first is exclusion scope. Removing a category of companies from a market-cap-weighted index removes a small share of total market capitalization, so the remainder still tracks the parent closely.
The second is sector-relative scoring. Best-in-class methodologies such as the MSCI ESG Leaders series select the highest-rated companies within each sector and hold sector weights near the parent index — which means every sector stays represented, including the ones an investor may have assumed were screened out. Neither choice is hidden. Both are stated in fund documentation, and neither is visible in the fund's name.
The published research is inconclusive. Black and Kölbel, analyzing 44,220 U.S. equity fund share classes from 2011 to mid-2024, find ESG funds charge gross expense ratios above non-ESG funds — 1.48% against 1.34% — but net ratios 9.5 to 12.7 basis points below them, because fee waivers offset the difference. YCharts, using a different universe, finds the opposite on an asset-weighted basis.
YCharts answered that one directly in August 2022, analyzing MSCI data across nearly 4,900 mutual funds and ETFs. U.S. equity funds marketed as ESG carried an asset-weighted expense ratio of 34 basis points. Funds in the same asset class with above-average ESG ratings but no ESG branding charged 25 basis points. The nine-basis-point difference is what the name costs, separate from what the screen costs. The figures are four years old and the fund universe has shrunk by roughly a third since, so treat the levels as dated and the comparison as the durable part.
The second cost is the one you actually bought the fund to avoid. You made a decision about where your money goes, believed it took effect, and it may not have. Nothing about that failure announces itself. A fund that holds what you were trying not to own performs exactly like a fund that doesn't — quarterly statements, tickers and returns look identical. The gap only appears when you look through the fund to the companies inside it.
That is a reasonable thing to want checked, and it takes a specific kind of data. Ziggma's Global Warming Potential estimates the temperature outcome implied by the emissions trajectories of the companies you own, aggregated to the portfolio level. For reference, the S&P 500 carries a Global Warming Potential of 4.1°C, and the MSCI ACWI 2.5°C. A sustainable fund sitting near its parent index will sit near its parent index's temperature figure too. That single number answers the question a fund name cannot: is this portfolio consistent with the outcome I thought I was funding? If it isn't, you have learned something about your holdings rather than about a marketing claim.
A fund can drop its sustainability label without changing a single holding. That is happening now, at scale, and no regulation is forcing it.
Labeled long-term sustainable mutual funds and ETFs available to U.S. investors numbered 997 as of July 31, 2026 — below a thousand for the first time since around the end of 2020. The count was 1,552 at the end of 2023, 1,383 at the end of 2024, and 1,176 at the end of 2025. Since 2023, 555 funds, share classes and ETFs have been liquidated, rebranded or merged, according to Sustainable Research and Analysis LLC using Morningstar data.
The Names Rule that governs fund names today was adopted in 2001 and has never been amended. It requires an 80% investment policy from funds whose names suggest a type of investment, an industry, or a geography. It does not reach names suggesting a characteristic.
A fund carrying one of those terms has no portfolio-composition obligation attached to its name. The only constraint is Section 35(d) of the Investment Company Act, which prohibits names the SEC finds materially deceptive or misleading. That is an enforcement standard applied after the fact, not a test the portfolio has to pass.
SEC Chair Paul Atkins told the House Financial Services Committee on February 11, 2026 that the Names Rule is among the rules he has directed staff to review for whether they are fit for purpose. The staff FAQ released alongside the extension addresses names containing “money market,” “growth” and “high-yield.” It says nothing about “ESG” or “sustainability.”
The labels are moving on their own, and the implication runs both ways. A fund that has dropped its ESG label may own exactly what it owned before. A fund that has kept one may have changed what it owns. Names and holdings have come apart, and no filing tells you which case you are in.
Regulators have looked, and found the same gap. Four SEC enforcement actions between 2022 and 2024 turned on the distance between what a fund said about its process and what the process actually was. Each firm settled without admitting or denying the findings.
The unit that brought most of these no longer exists. The SEC created its Climate and ESG Task Force in March 2021 and disbanded it in September 2024, saying the expertise developed there now sits across the Division of Enforcement. ESG had already been dropped from the Division of Examinations' 2024 priorities. Enforcement has not stopped — the WisdomTree settlement came a month after the task force closed — but no specialist team is looking for these cases, and the naming rule that would set a testable standard is still years out.
ESG ratings are the tool most investors reach for here, and they answer a different question. An MSCI or Sustainalytics rating estimates how environmental, social and governance factors bear on a company's financial value — risk to the company, and so to the investor who owns it. It does not estimate the company's effect on the world. A company can score well because it manages its exposures competently while the exposures themselves remain intact.
The providers also disagree with each other. Berg, Kölbel and Rigobon put the average pairwise correlation across six major rating agencies at 0.54. Both points are covered in full in our guide to reading an ESG rating and our analysis of whether ESG funds outperform.
A fund label cannot be verified from outside the fund. The companies inside it can. That is the whole of the claim, and it is why Ziggma reports impact at the holding level rather than the fund level.
The Ziggma Impact Score rates a company's effect on the world on a 0–100 scale, in five bands: Harmful, Negative, Mixed, Positive and Profound. It rests on four sub-scores — Climate Action, Resource Use, Fair Labor and Accountability — computed by ACA Ethos. Scores roll up from the companies you own to the portfolio, so a fund's score is the weighted result of its holdings rather than a description of its mandate. That distinction is the point: the score reflects what a fund owns, not what it says.
The Ziggma Controversy Score summarizes documented incidents and disputes attached to a company, on a 0–100 scale where higher indicates more. Separately, ACA Ethos assesses revenue exposure to harm categories, so a company's involvement is measured as a share of revenue rather than recorded as a yes or no. A screened fund holding a company with material revenue in an excluded category will show it here, whatever the fund is called.
Ziggma's Global Warming Potential estimates the temperature outcome implied by the emissions trajectories of the companies in a portfolio. Each holding carries its own figure, and the portfolio figure is the aggregate. For reference, the S&P 500 carries a Global Warming Potential of 4.0°C and the MSCI ACWI 2.5°C. Comparing a fund's figure with its parent index's is a direct read on whether the screen changed the climate outcome or only the name. The same holding-level data drives the ESG and impact stock screener, and it is the raw material for building a greenwashing-free portfolio.
