Assessing the Relationship Between Financial Performance, ESG Reporting, and Corporate Value: Evidence from the Portuguese Stock Market

This study examines the relationship between financial performance, ESG reporting, and corporate value. The study uses content analysis of non-financial reports of Portuguese listed corporations from 2019 to 2022 to construct a comprehensive ESG disclosure index, based on GRI standards, as well as the respective environmental, social, and governance sub-indices. Panel regression models are used to investigate whether financial performance increases ESG reporting and whether ESG reporting enhances corporate value, while controlling for firm size, sector, and reputation. The results show that financial performance has no significant impact on ESG reporting. Only firm size seems to positively and significantly impact ESG reporting. This finding supports the prior literature linking larger and more visible firms to higher ESG disclosure levels. Furthermore, the results show that ESG reporting does not significantly impacts corporate value. Instead, corporate value is negatively and significantly affected by firm size. This result suggests that larger and more mature firms may derive comparatively fewer valuation benefits from ESG reporting, in line with recent evidence. Overall, the results suggest that structural firm characteristics (notably firm size) play a more decisive role in shaping ESG reporting and corporate value.