Firm‐Size Heterogeneity in the Effects of ESG Disclosure on Firm Value Under Institutional Reform: Evidence From Japan
利用2019-2023年1427家日本上市公司面板数据，研究发现东京证券交易所重组和公司治理准则修订后，ESG披露对企业价值的影响因企业规模而异：改革前大企业受益，改革后仅超大企业仍有正面效应。
ABSTRACT Focusing on firm‐size heterogeneity, this study examines how institutional reform reshapes the effects of environmental, social, and governance (ESG) disclosure on firm value. Using 2019–2023 panel data on 1427 Japanese listed firms (before and after the 2022 Tokyo Stock Exchange reorganization and Corporate Governance Code revision), this analysis investigates how the valuation consequences of ESG disclosure vary across institutional conditions. Correlated random‐effects (CRE) and CRE–two‐stage least squares models using industry‐average ESG disclosure as an instrument show size‐based differences. Before the reforms, ESG disclosure was mainly associated with firm value among large firms, while mid‐sized enterprises tended to experience negative valuation effects. After the reforms, stronger coercive pressures and standardized disclosure requirements weakened valuation benefits for most large firms, with positive effects tending to be confined to only very large firms. Overall, quasi‐mandatory disclosure improves transparency but reduces strategic differentiation, highlighting the need for more proportionate ESG disclosure frameworks.