What Sustainable Finance Still Gets Wrong

Sustainable finance is often discussed as though its central question is one of alignment: can financial markets support environmental goals without sacrificing the returns? Through this Practicum, I have come to see the question differently. The more pressing issue is not whether sustainability belongs in finance, but how markets are actually processing sustainability once it becomes visible, measurable, and economically relevant. Before this project, I understood sustainable investing primarily through the lens of climate disclosures, ESG ratings, and investor messaging. Engaging with academic literature, however, has pushed me to think more critically about what truly moves capital, which risks remain mispriced, and where investor behavior may still fall short of environmental realities. Sustainable finance, I have learned, is not only about values. It is equally about perception, pricing, and limits of current market signals.

Hartzmark and Sussman (2019) helped me understand just how powerfully investor preferences can shape capital allocation. Using Morningstar’s 2016 sustainability ratings as a natural experiment, they find that funds labeled as low sustainability experienced net outflows exceeding $12 billion, while high-sustainability funds attracted net inflows of over $24 billion. At first glance, these figures confirm a hopeful narrative: investors care, and sustainability labels can redirect capital at scale. Yet, the paper is more nuanced. The authors also find no evidence that highly rated funds outperform low-rated ones, suggesting that investor behavior is driven not only by return expectations, but also by positive affect and non-pecuniary motives. This finding struck me because it reveals that sustainable finance is shaped partly by genuine ethical preference and partly by how sustainability is framed and made legible through existing market infrastructure.

What makes this paper especially valuable for my Practicum work is how it complicates the assumption that market demand for sustainability reflects rational repricing. If investors reward sustainability because it feels safer or more future-oriented, that may still direct money toward better outcomes, but it does not mean markets are measuring environmental value with precision. A sustainability rating can make an issue visible, but visibility is not the same as accuracy. In my practicum, where I am building a financial model for carbon credit transactions, this gap is tangible: the pricing of a credit depends on verification standards and registry frameworks whose rigor varies widely, yet the label of “carbon credit” can lend an impression of uniformity that hides real differences in environmental integrity. Hartzmark and Sussman’s work made me more attentive to the gap between a sustainability signal’s salience and its substantive rigor, which is a gap that shapes how blended finance transactions are ultimately structured and valued.

Giglio, Kuchler, Stroebel, and Zeng (2023) broadened my perspective further by arguing that biodiversity loss constitutes a financially material risk that remains underdeveloped in both academic research and market practice. Crucially, they demonstrate that biodiversity risk and climate risk are only weakly correlated across industries, meaning biodiversity cannot simply be absorbed into existing climate frameworks. They also present evidence that biodiversity risk is already affecting equity prices, while survey data reveals that many market participants believe these risks remain inadequately priced. This paper reshaped how I think about environmental risk categorization. Climate change tends to dominate sustainable investing discussions, but biodiversity loss raises equally serious physical and transition risks for sectors including energy, utilities, real estate, and pharmaceuticals. These are sectors that intersect directly with the infrastructure finance career I am pursuing, and it is striking to consider how few project finance underwriting processes currently incorporate biodiversity exposure as a standalone risk factor.

Taken together, these two papers expose a tension I now see as central to sustainable finance. Hartzmark and Sussman show that investors are willing to move capital in response to sustainability signals, yet Giglio and his coauthors show that an environmentally significant risk can remain only partially priced even when its economic consequences are substantial. The implication is that sustainable finance is not progressing evenly toward better pricing of environmental externalities. Some risks become visible because they are easier to label, rank, and communicate; others remain underpriced because they are complex, slower-moving, or lack standardized measurement. For finance professionals, the challenge extends beyond responding to existing ESG signals. It requires actively identifying what markets may still be missing, whether that means developing biodiversity-adjusted due diligence in project finance, or scrutinizing whether a carbon credit’s price reflects genuine additionality rather than the convenience of a familiar label.   

References

Hartzmark, S. M., & Sussman, A. B. (2019). Do Investors Value Sustainability? Journal of Finance.

Giglio, S., Kuchler, T., Stroebel, J., & Zeng, X. (2023). Biodiversity Risk.