高碳排產業公司碳排放與相關事件對公司市值影響之研究

The Effects of Carbon Emission and Related Events on Firm Value

劉議鎂(Yi-Mei Liu)

指導教授 ： 陳坤志

共同指導教授 ： 黃祥宇(Xiang-Yu Huang)

國立臺灣大學/管理學院/會計學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202200952

摘要

近來全球暖化問題日益嚴重，不僅政府紛紛制定監管措施、立下碳中和目標，企業亦投入減碳的行動，展現對環境保護的企業社會責任，不論是將碳資產負債反應於財報中，或是在企業社會責任報告書中說明，可能都是利害關係人會關注的資訊，但一般來說，投資人還是會優先考量短期財務的報酬，是以為了探究投資人如何看待企業碳排放量、進而影響企業價值，本研究以美國高碳排放公司為樣本，探討企業碳排放量與公司價值之關聯性，並透過迴歸模型進行實證分析。另一方面，本研究亦搜集樣本期間(2016 年至 2020 年)內影響企業碳排放監管政策之事件發生時對公司股價造成的影響，並以事件研究法分析市場對有關影響企業碳排放量之事件的反應。

　　研究結果發現企業碳排放量與價值呈現負相關，代表碳排放量越多的企業，其公司價值將會越低，尤其對屬於相對低碳排放產業之企業來說，兩者之負面效果更加明顯，本研究更進一步發現屬於相對低碳排產業之企業，超額碳排放量對其價值的負面影響又較一般碳排放量大。至於事件研究的結果則是說明，當有關加以限制企業碳排放量的事件發生或消息被釋出時，公司股價會有負的異常報酬，反之，當事件或消息為寬鬆企業碳排放量管制時，公司股價會有正的異常報酬。綜上，實證結果反映出投資人視碳排放量為不利於企業價值之因子，同時亦會關注影響企業碳排放量的消息、受事件影響對公司的評價。

關鍵字

碳排放量 ； 公司價值 ； 事件研究

並列摘要

With the severity of global warming, not only do governments make policy concerning controlling carbon emissions and achieving carbon neutrality, but enterprises also devote to reducing carbon emissions and show their responsibility to environment. In order to understand whether and how investors pay attention to a company’s carbon emissions and thus have impact on firm value, the research investigates the relation between carbon emissions and firm value with data from U.S. EPA. On the other hand, we also collect events which might affect the available amount of carbon emissions between 2016 and 2020 to understand whether and how market reacts to certain events.
The result indicates that carbon emissions have negative effect on firm value, i.e., the more carbon emissions the firm releases, the lower the firm value is. Moreover, the negative effect caused by excessive carbon emissions is greater than that caused by basic emissions to company in relative low emission industry. As for the results of event study, we find that company stock price will increase with relaxing carbon emission policy released; while the stock price will decrease with strict carbon emission policy released. In sum, the research shows that investors consider carbon emissions unfavorable to company and also will follow news regarding carbon emissions.

並列關鍵字

carbon emissions ； company value ； event study

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