- 學位論文
2017年減稅與就業法案：稅率對研發費用的關係
How Does Corporate Tax Rate Affect Firm R D Expenditure Under the Tax Cuts and Jobs Act of 2017?
摘要
本文以COMPUSTAT涵蓋公司的年資料進行實證分析，使用研發資產比、研發營收比、研發市值比作為衡量公司研發費用的指標，探討2017年減稅與就業法案(Tax Cuts and Jobs Act)後，稅率對企業研發費用的影響。首先，本文依照企業有效稅率與研發費用進行調整後差異中之差異迴歸分析(Modified DID)。其次，考量到研發具有其產業特性，進一步將公司衡量研發費用之指標依據產業中位數進行調整後再採差異中之差異迴歸分析(Modified DID)，檢視在控制其他變數的情況下，減稅及就業法案(TCJA)和企業研發支出是否存在關係。最後本文在上述研究方法下，發現減稅及就業法案(TCJA)後，企業研發費用與稅率的關係並未有立即性的變化。 為了探討不同特性公司面對減稅及就業法案(TCJA)之研發費用影響，本文根據有無廣告費用作為分類準則，將樣本分為兩群進行差異中之差異迴歸分析(Modified DID)，發現無論有無廣告費用，在減稅及就業法案(TCJA)後，稅率與研發之關係同樣未有立即性的變化。整體而言，減稅及就業法案(TCJA)後，稅率和研發費用之負向關係並沒有明顯改變，本文認為是因為企業研發為一長期性的規劃，短期內不容易調整所致。
並列摘要
This paper studies the impact on the relationship between effective tax rate and R D expenditure after the enforcement of Tax Cuts and Job Act (TCJA) in 2017.We collected the company data from COMPUSTAT, and use R D-asset ratio, R D-sales revenue ratio and R D-market value ratio as the companies’ R D expenditure indicators. First of all, this paper used Modified Difference in Differences (Modified DID) to examine the relationship between effective tax rate and R D expenditure before and after TCJA. Next, this paper adjusted R D expenditure with industry median then execute Modified DID again. In these two parts, we analyzed if TCJA would affect the relationship between effective tax rate and R D expenditure under considering control variables. Eventually, we found out that there is negative correlation between effective tax rate and R D expenditure and this correlation would not be affected after the enforcement of TCJA. To explore the correlation between effective tax rate and R D expenditure under different company trait, this paper divided the data in two groups by using advertisement fee or not and use Modified DID again to examine it. We find that no matter with or without advertisement fee, the correlation between effective tax rate and R D expenditure would not be affected. Overall, the empirical results of the sample indicate the correlation between effective tax rate and R D expenditure would not be affected after the enforcement of TCJA. We concluded that is because R D expenditure is a long-term project for companies and it is not easy to be adjusted in short term.