本文利用台灣2010年降低營利事業所得稅稅率之改革，檢驗公司稅率對受雇員薪資之影響。與過去文獻不同之處為，本文考量稅率與公司決策互相影響而產生內生性，因此以工具變數進行兩階段最小平方法以避免產生偏誤。並以綜合所得稅與營利事業所得稅資料對全體受雇員之個體進行分析，而非僅針對上市櫃之公司。最後發現有效稅率下降1% 能提升台灣整體受雇員平均 0.16% 的薪資。而考量個體異質性下，進行次組分析，發現在技術密集產業、大型公司、公司頂層員工所受到的影響較大；而其他產業，中小型公司以及公司基層員工的薪資受到稅率的影響較小，使得政府稅改政策並不如預期提升全民薪資。 / This paper estimates the effect of corporate income tax rate on wage by using the Taiwan Corporate Income Tax Reform of the year 2010 as a natural experiment. Different from the previous literature, we consider the endogenous relationship between the tax rate and the policy of the company. Thus, the two stage least squares method is used to overcome the endogeneity bias. Additionally, our participants include all the individual employees from the data of Individual Income Tax and Corporate Income Tax rather than only the employees of listed company. Our results indicate that a drop of 1% in corporate income tax rate would increase the wage by 0.16%. Furthermore, we test for the heterogeneous firm and worker effects by using subgroup analysis and find the technology-intensive industries, the large companies and the high-classed employees within firm have a greater impact. On the other hand, the non-technology-intensive industries, the small and medium company and the low-classed employees within firms have a smaller impact. Therefore, the Tax Reform didn’t increase the overall wage as expected.

2009年底促產屆滿後，立法院於當年5月將營所稅由25%調降至20%，隔年5月再由20%調降為17%；接續促產的產創條例大幅取消各項投資抵減，期望能改善產業間租稅負擔公平，並藉由營所稅減免來提升員工就業與薪資。本研究使用2006~2013年TEJ資料庫上市櫃公司資料，發現高科技產業的有效稅率在營所稅改革後明顯上升，傳統產業則明顯下降，其他產業幾乎沒有變動。我們因而以其他產業做為控制組，高科技產業和傳統產業分別為兩組實驗組，採DID模型檢驗稅制變動對兩實驗組員工薪資和就業影響。研究結果發現，在薪資方面，高科技產業沒有顯著變化，傳統產業則呈現顯著的下降；在雇用人數上，高科技和傳產雇用皆為不顯著。整體而言，此次政策施行縮小了產業間租稅負擔的差距，但對於增加員工薪資水準及創造中小企業就業機會上效果並不顯著。 / After the termination of Statute for Upgrading Industries at December 31th, 2009, Taiwanese government has reduced the Enterprise Income tax rate from 25% to 17% and, subsequently, kept only R&D tax credit and provided grants to small and medium enterprises that recruit additional employees in the Statute for Industrial Innovation. Using the financial reports of listed companies from 2006-2013, this study examines the impact of enterprise income tax reform in 2010 on the number of hiring and employed wages. Our study first indicates that ETR of high-tech industry gets higher, traditional industry becomes lower, and the remaining industries almost stays the same after the reform. Therefore, we employ companies in the remaining industry as the control group, those in the high tech and traditional industry as the treatment groups, and conduct the analysis using the difference-in-difference estimation method. Our results show that, for the employee’ wage, there’s negative response on traditional industry and no significant change on high-tech industry. In addition, this reform didn’t increase the employee number of small and medium enterprises. This paper points out that, reform of the tax system can change the tax rate of industries, but can’t achieve the expectation of increase in wage and employment of small and medium enterprises.