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ISO认证能否提升企业价值呢 ?本文研究我国上市公司获得ISO90 0 0质量管理体系和 1 4 0 0 0环境管理体系认证与股票超额回报之间的关系 ,并检验公司规模在ISO认证与股票超额回报之间关系中所起的作用。实证分析表明 :在认证公告日 ,股票市场会产生正的超额回报 ,但是除认证公告日以外其余时间的超额回报和累计超额回报都不显著 ,即使是在认证公告当日 ,股票的超额回报也很小。这说明在我国股票市场上 ,ISO认证能够对股票价格产生影响 ,但影响范围和作用力度很有限。ISO认证对股票超额回报的影响 ,随公司规模增大而下降 ,这与信息假说的理论分析结果相一致。
ISO certification can enhance the value of the enterprise? This paper studies the Chinese listed companies to obtain ISO90 0 0 quality management system and the 2004 environmental management system certification and stock excess returns, and test the scale of the company in the ISO certification and stock excess The role of the relationship between the return. The empirical analysis shows that: on the certification announcement day, the stock market will have a positive excess return, but excess return and accumulated excess return are not significant in the rest of the period except for the certification announcement day. Even in the day of the certification announcement, the excess returns of the stock small. This shows that in China’s stock market, ISO certification can have an impact on stock prices, but the extent of the impact and the role of the intensity is limited. The impact of ISO certification on excess stock returns declines with the size of the firm, consistent with the theoretical analysis of the information hypothesis.