Han Pham

Job Market Paper

Biodiversity Footprints and the Cross-Section of Stock Returns

Abstract: I study whether firms' negative impact on biodiversity is priced in global equity markets, using firm-level biodiversity footprints for more than 10,000 listed firms across 57 countries. Footprints are highly concentrated in consumer staples, energy, and materials, strongly right-skewed, tightly rank-correlated across environmental pressure channels, and closely tied to firm size and greenhouse-gas emissions, so that a portfolio sorted on the raw footprint is largely a bet on size. Around the 2021 Kunming Declaration, high-footprint firms earn lower abnormal returns on the adoption day, but the event day is not distinguishable from ordinary days once the estimation window is widened. In a long-short strategy, once firms are sorted on their footprint within size quintiles, high-footprint firms outperform low-footprint firms by roughly half a percentage point per month from November 2021 to December 2025, significant at the five percent level in every specification that includes a brown-minus-green carbon factor. Neutralising size exposes a second imbalance: conditional on market capitalisation, high-footprint firms tilt toward value. The premium survives within countries and within sectors, though it is estimated over a single macro cycle.

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Working Papers

Climate Fairness and Growth: Allocating the Remaining Carbon Budget (with Galina Hale, Michael Halling, and Nora Paulus) NBER WP34978  CEPR DP21287  SSRN   

Work in Progress

Subsidies and Household Technology Adoption: Evidence from the Belgian Auto Market (with François Koulischer, Christophe Spaenjers, and Justin Delloye)