Who Needs the ESG Score?
How investors are reshaping the relationship between ESG ratings, information and judgement
In 2023, corporate ESG ratings sat joint top of the list of the ESG information sources investors found most useful for investment decisions, chosen by 53 per cent of respondents. In the ERM Sustainability Institute’s 2026 survey they have fallen to sixth, chosen by 31 per cent, behind in-house research, direct engagement with companies, and corporate sustainability reports (ERM Sustainability Institute, 2026, p. 27). Fifty-eight per cent of respondents still use ESG ratings products and services at least once a week, and only a third expect the relevance of ESG ratings to decline over time (ERM Sustainability Institute, 2026, pp. 28, 37). Investors have not walked away from the providers; they appear to be changing what they take from them.
The comparison needs care. The 2026 survey drew on 53 investment professionals against 33 in 2023, and it adds asset owners, private equity, and venture capital to a sample previously dominated by asset managers, banks, and mutual funds (ERM Sustainability Institute, 2026, p. 15). Eighteen per cent of 2026 respondents, largely from private equity and venture capital, never use ESG ratings products, against none in 2023 (ERM Sustainability Institute, 2026, p. 28). The movement between the surveys is suggestive, no more. Underlying third-party ESG data also lost ground, falling from 44 to 33 per cent, so the survey records no simple substitution of data for scores (ERM Sustainability Institute, 2026, p. 27).
The more revealing evidence concerns use. Asked how they employ ESG ratings and their underlying data, 61.5 per cent of respondents said as a basis for further in-house research and 59 per cent as a basis for engagement with companies. Collecting underlying data for proprietary modelling drew 38.5 per cent, and collecting top-level and sub-level scores for investment decisions 28.2 per cent (ERM Sustainability Institute, 2026, p. 31). More than a quarter therefore use final scores directly, and respondents could select several uses; the pattern shows the score most often serving as a starting point for the investor’s own work. One UK asset owner said third-party data would demand a "disproportionate internal resource effort to reproduce" (ERM Sustainability Institute, 2026, p. 19).
If investors still need what ESG rating providers collect, but increasingly wish to decide for themselves what it means, what exactly are they purchasing? The evidence points towards a possible reallocation of evaluative labour. Producing ESG information (collecting, estimating, classifying and standardising it) remains heavily outsourced, while some sophisticated investors keep control of what that information signifies, which indicators matter and how they are weighed. That division of responsibilities is observable today. Whether it is spreading, and whether it is new, the available evidence cannot yet establish: proprietary rating systems such as Amundi’s are not recent inventions, and two surveys of differing composition do not make a trend. The consequences that attach to an external judgement once markets build it into their machinery are where the comparison with credit ratings becomes instructive.
