自願性環保資訊揭露對公司價值之影響

本研究旨於探討公司自願揭露環保支出資訊對公司價值的影響，並檢視投資人對不同揭露項目評價的差異。鑒於法令修改後賦予公司較大揭露彈性，本研究以2007年至2010年台灣上市公司為研究樣本。於考量自願性揭露行為可能與公司特性具相關性，本研究採用二階段最小平方法（2SLS）處理樣本自我選擇問題。實證結果顯示，自願性揭露環保支出資訊對公司價值有正向影響，但未發現強制性揭露與公司價值具有關聯性。此外，各項自願性揭露效果不一，並非所有自願性環保支出資訊揭露皆能驅動公司價值，本研究發現，環保支出造成競爭地位變化的資訊對公司價值的影響程度相較於其他揭露項目大，亦即自願性揭露環保支出資訊對公司價值的正向作用主要來自競爭地位影響資訊所致。公司自願揭露更多的環保支出資訊，主要因素為競爭地位變化相關的訊息將可消弭投資人的疑慮，裨益公司價值的提升。

關鍵字

環保揭露資訊；公司價值；自願性揭露；二階段最小平方法

並列摘要

The purpose of this study is to explore the relation between the voluntary disclosures on environmental protection expenditure and firms value, observed the differences of the evaluation of disclosures items of environment by investors. There are more flexible options for firms to disclose the environmental information after the revise of the Act, this study selects the empirical samples from TWSE in the year 2007 to 2009. The firms' voluntary disclosures relate with some characteristics of firms, so the two-stage-least-square (2SLS) is introduced into this study to handle self-selection problem. Finally, this study finds there is significantly positive influence on the voluntary environmental disclosures to the firms, but there is not significantly influence on the mandated environmental disclosures to the firms. Besides, each voluntary disclosure item has different force, some disclosures would have influence value but some would not. This study finds that the competitive position of the disclosure item is more significantly influence value than others, which mean the main influence with firms value from the voluntary environmental disclosure is the item of competitive position. Firms disclose more environmental information voluntarily, especially the item of competitive position, would dispel investors' doubt, and improve the firms value.