Does stock market index adjustment affect environmental information disclosure? Evidence from China
基于中国沪深300指数调整，研究发现纳入指数显著提升了企业的环境信息披露质量，且这一效应在代理成本较低和法律环境较强的企业中更明显。
This study empirically investigated the effect of adjustment of the China Securities Index 300 (CSI 300) on environmental information disclosure (EID) by index constituents, based on propensity score matching and difference-in-difference approaches. The results showed that the inclusion in the CSI 300 significantly improved the quality of EID by firms. Moreover, this positive impact was more pronounced among firms with lower agency costs and those located in regions with a stronger legal environment. Further testing of the mediating mechanism revealed that becoming an index constituent served to curb opportunistic behavior by managers arising from shortsightedness. Our results were valid after addressing the potential endogeneity between index adjustment and EID and remained unchanged in various other robustness tests. The findings provide support for the positive impact of stock market index adjustment on non-financial information disclosure and have practical implications for decision-making regarding EID in China and other emerging markets.