ESG Performance and Market Reactions to Seasoned Equity Offerings: Evidence on a non-linear relationship and its implications for policymakers and finance actors

This policy brief summarizes new evidence on how stock markets react to environmental, social and governance (ESG) performance when listed firms raise fresh equity capital. The underlying study examines 872 seasoned equity offering (SEO) announcements by 408 U.S. manufacturing firms between 2016 and 2023. Because SEO announcements are typically unexpected and efficiently priced by financial markets, they provide a useful setting for assessing investor responses while reducing reverse-causality concerns that often affect ESG-performance studies. The core finding is that there is no simple linear "more ESG is always better" relationship. Instead, the study documents an inverted U-shaped association for the overall ESG score and, more clearly, for the social pillar in the post-2020 period. Firms with moderate social scores receive the most favorable short-term market reactions, while both lower and higher scores are associated with lower announcement returns. By contrast, environmental scores are negatively associated with short-term market reactions after 2020. The study finds no link between ESG performance and longer-horizon buy-and-hold abnormal returns or SEO underpricing. For policymakers and finance actors, the main message is one of caution. Aggregate ESG scores can hide materially different pillar effects; non-linear patterns matter; and evidence from earlier periods may not travel well to today's market environment. ESG information appears most useful when it is material, credible and interpreted in context rather than treated as a monotonic signal of lower financing risk.