Rethinking the Real Impact of Sustainable Investing

Sustainable investing has changed over the past decade from a specialized approach to a key component of international finance. As I engaged more deeply with both academic literature and practicum work, I began to question a key assumption underlying this trend: does ESG investing genuinely bring about significant real-world change, or does it simply reshape capital allocation without fundamentally altering corporate behavior? In assessing what sustainable finance is actually accomplishing in practice, this distinction between financial signaling and genuine impact has grown in significance.

According to a significant amount of research, investors do react to sustainability signals, but not always in the way we might expect. For instance, Hartzmark and Sussman (2019) offer causal evidence that sustainability ratings have a big impact on fund flows: highly rated funds attract substantial inflows, while poorly rated ones experience outflows. This indicates that ESG information is clearly priced into investor decisions. However, the same study finds no consistent evidence that higher sustainability ratings lead to better financial performance. Taken together, this creates a tension: if ESG attracts capital but does not necessarily improve returns, then investor demand may be driven as much by perception, preferences, or signaling as by fundamentals.

This tension becomes more evident when we look at how investors integrate ESG into decision-making. Edmans, Gosling, and Jenter (2024) demonstrate that most portfolio managers incorporate environmental and social factors primarily to enhance financial returns or manage downside risk, rather than to maximize social impact. In other words, ESG is frequently treated as an input to traditional financial analysis, rather than as an end goal. Even among funds marketed as “sustainable,” few investors are willing or able to sacrifice returns due to fiduciary obligations. This indicates that ESG investing operates within a framework where financial performance remains the primary constraint, potentially limiting its capacity to generate meaningful external impact.

Building on this, the central question is not just whether investors value ESG, but how their actions translate into tangible real-world outcomes. Caldecott et al. (2024) outline three mechanisms through which sustainable finance can influence the real economy: changes in firms’ cost of capital, access to liquidity, and corporate practices. Notably, many ESG strategies, particularly passive approaches based on screening or ratings, do not strongly activate these channels. Merely reallocating capital toward “greener” assets, without influencing how firms are financed or how they operate, may have limited effect. This distinction helps explain why the authors caution against conflating portfolio alignment with actual environmental or social outcomes, a gap increasingly referred to as “impact-washing.”

Reflecting on these findings, I have come to view sustainable investing as a spectrum of strategies with varying levels of effectiveness, rather than as a single unified approach. On one end, ESG ratings and disclosures play an important role in improving transparency and shaping investor expectations. On the other, approaches such as active ownership and engagement appear more directly connected to influencing firm behavior. This distinction also resonates with my practicum experience, where much of the current ESG ecosystem is highly effective at organizing information and guiding capital flows, but continues to evolve in translating these efforts into consistent, measurable real-world outcomes.

Ultimately, this reflection has shifted my perspective from asking whether ESG investing “works” to considering the conditions under which it can be most effective. Sustainable finance has the potential to contribute meaningfully to addressing long-term global challenges, particularly when financial strategies are aligned with mechanisms that influence corporate decision-making. As the field continues to develop, greater clarity around impact pathways and more active forms of investor engagement may further strengthen the connection between financial markets and real-world outcomes. In this sense, ESG investing should be understood as an evolving framework with growing potential, rather than as a finished solution.

References:

1. Hartzmark, Samuel M. and Sussman, Abigail B., Do Investors Value Sustainability? A Natural Experiment Examining Ranking and Fund Flows (March 25, 2019). European Corporate Governance Institute (ECGI) - Finance Working Paper No. 565/2018, Available at SSRN: https://ssrn.com/abstract=3016092 or http://dx.doi.org/10.2139/ssrn.3016092
2. Edmans, A., Gosling, T., & Jenter, D. (2021). CEO Compensation: Evidence from the Field. SSRN Electronic Journal. https://doi.org/10.2139/ssrn.3882361
3. ‌Caldecott, B., Clark, A., Harnett, E. et al. How sustainable finance creates impact: transmission mechanisms to the real economy. Rev World Econ 162, 87–119 (2026). https://doi.org/10.1007/s10290-024-00541-9