企業綠色投資有助于我國企業建立良好的社會聲譽,實現企業的可持續發展。本文試圖從環境稅的角度,探討環境稅對企業綠色投資的邊際效應是正向還是負向?環境稅對企業綠色投資效應是否具有異質性?本文運用我國重污染行業上市公司的2008-2013年的經驗數據,用分位數回歸的研究方法對環境稅的企業綠色投資效應進行了研究。分位數回歸方法相比普通最小二乘法回歸,分位數能夠更全面的描述自變量對于因變量的變化范圍以及條件分布形狀的影響;分位數回歸方法與最小二乘法使用殘差平方和為最小化的目標函數相比,不易受到極端值的影響,估計結果更為穩健。研究發現:環境稅對企業綠色投資的邊際效應為正向并具有異質性,表現在:1從平衡面板的固定效應模型估計結果來看,環境稅對企業綠色投資投資額的影響是正向的,換句話說,在其他因素不變的情況下,隨著環境稅額的不斷提高,企業綠色投資額也會隨之提高;2從面板分位數回歸的估計結果來看,環境稅對企業綠色投資的邊際效應為正向并具有異質性,即低分位企業的環境稅綠色投資效應為正,但并不顯著;高分位企業的環境稅綠色投資效應為正,但呈遞減趨勢;中間分位企業的環境稅綠色投資效應為正,并呈遞增趨勢。本文研究結果的啟示是:1環境稅的出臺具有積極的意義;2環境稅的相關法律制定要注意因企業制宜,考慮企業承擔能力的同時兼顧效率和公平。本文研究結果為環境稅的出臺提供了證據支持、為完善環境稅的設計提供了經驗證據。

Enterprise green investment assists China’s enterprises in improving their environmental sustainability and international reputation. The present article examines the marginal effects on enterprise green investment of China’s environmental tax structure. In particular,it asks: Do environmental taxes have a positive or negative effect on green investment? And,are these green investment effects uniform or heterogeneous across firm categories? Environment tax effects on enterprise green investment are estimated with quantile regression methods,drawing on the companies listed among China’s heavy-pollution industries in the 2008- 2013 periods.For this purpose,the quantile regression method is compared with ordinary least squares regression( OLS). The quantile approach is more flexible than OLS is in representing the effects on the dependent variable of changes in the independent variables. It particular,it allows for the separate influences of conditional distribution shapes on statistical outcomes. Because OLS is comparatively insensitive to regression effects near the extreme values of the data,quantile regression is the more accurate and more robust when effects near the extremes differ from those near the center. In general,it is found that an environmental tax’s marginal effects on enterprise green investment are positive,but differ widely across enterprise sub-samples. In a fixed-effects OLS model,an environmental tax is observed to have a broadly positive impact on enterprise green investment. In other words,holding factors other than the environmental tax constant,enterprise green investment rises continuously with a rise in the environmental tax. In a quantile regression model,the environmental tax also has positive effects on green investment,but in magnitudes that differ across the sub-groups of firms employed in the analysis. And to be specific: 1Among firms with relatively low green investment,the environmental tax’s green investment effects are positive but not significantly different from zero. 2Among firms with very high green investment,the tax’s investment effects are positive and statistically significant,but are rather low,and very low among the very high-green-investment companies. 3Among firms with an intermediate amount of green investment,a green tax ’s green investment effects are not only positive and statistically significant,but are especially large. Furthermore,the effects rise as the larger green-investment companies in this intermediate group are encountered. In summary,the study finds that: 1 The environmental tax has a significantly positive effect on enterprise green investment,especially among firms with currently intermediate amounts of green investment; 2 In structuring environmental taxes,government should consider not only economically efficient pollution control,but factors such as the enterprise’s financial endurance.These conclusions have direct relevance for the environmental taxes soon to be instituted in China.