企業發行綠色債券之宣告效果

Abstract

有鑑於近年來氣候環境轉變劇烈，無論是政府、社會大眾或是企業對環境保護的重視程度皆有所增加，故有新興金融工具—綠色債券—的問世。過去許多文獻曾探討一般債券及可轉換債券發行後對公司股價所帶來的影響 (Spiess and Affleck-Graves (1999) ; Mitchell and Stafford (2000) ; Lewis, Rogalski, and Seward (2011))，但對新崛起的綠色債券之宣告效果則著墨不多。本論文研究 2014-2017 年間美國企業所宣告發行的綠色債券，發現債券宣告發行後，短期內並無顯著宣告效果，然股票長期累計超額報酬顯著為負，且跌幅超過 30%，多元迴歸分析也顯示發行綠色債券與宣告後長期累計超額報酬為顯著負相關。我們認為發行綠色債券的資金用途較為受限，再加上其帶來的規範與監督成本，使綠色債券不一定能為公司績效帶來正面效應。此外，綠色企業債券樣本數尚且不多，個別公司股價劇烈波動易影響整體事件之超額報酬。

Witnessed the drastic changes in the climate and environment in recent years, the government, society, and corporations have increased their emphasis on environmental protection. Therefore, green bonds have emerged as an innovative financial instruments. Past literatures have discussed the impact of the issuance of straight bonds and convertible bonds on the company’s stock performance (Spiess and Affleck-Graves (1999); Mitchell and Stafford (2000); Lewis, Rogalski, and Seward (2011)). Since the green bond is a fairly new instrument, very few literatures have discussed its impact. After investigating the green bonds which announced during the period 2014 to 2017 in the United State, we find that the cumulative abnormal return of the announced events is significantly negative in the long run, with less than -30%. Multiple regression analysis also shows that the green bond issuance and the cumulative abnormal return is negatively correlated. We suggest that the limited usage of capital that raised by green bonds, as well as the additional compliance and monitoring costs it brings, may be the reasons why green bonds do not necessarily have a positive effect on firm performance. In addition, the number of green corporate bond samples are relatively small, the sharp share price fall in individual firm can easily affect the abnormal returns overall.