公司所得稅稅率對企業短漏報行為之探討

Abstract

為使稅制達到公平，稽徵機關每年須耗費大量稽徵人力及資源查核營利事業所得稅申報資料，其行動並非為開罰逃漏稅負廠商，而是藉此防杜營利事業逃漏稅負，降低納稅義務人未來逃漏動機，提升租稅遵從程度。過往針對營利事業逃漏或短漏報稅負之研究，由於中小企業課稅資料取得不易，因此大多使用上市上櫃公司所公布之財報為研究資料，因此研究對象及方法受限，故推論較無一般性結論。而在研究稽徵機關政策工具對納稅義務人逃漏之影響，多為理論分析或針對個人實證研究，因此所得稅稅率對廠商短漏報行為之遏阻效果較無一致結論。針對此議題，本研究利用台灣2010年降低營利事業所得稅稅率及促進產業升級條例落日之改革，檢驗公司稅率對其短漏報行為之影響，並使用財政部財政資訊中心建立之營利事業所得稅申報及核定檔，做為研究樣本來源。同時考量有效稅率與公司決策交互影響所產生的內生性問題，因此以工具變數進行兩階段最小平方法估計以避免偏誤。實證結果顯示當公司所得稅稅率下降1%，短漏報稅額下降1.03%，因此公司短漏報行為的下降不但可彌補稅收降低產生的損失，亦可降低稽徵機關在查核資源上的分配，使稽徵效率提升。

In order to achieve fairness in the tax system, the national taxation bureau must spend a large of manpower and resources every year to check the business income tax returns data, it’s not to impose a forfeit for evasion company, but to prevent the company to evade income tax, increase tax compliance.Reviewing the study of tax evasion, tax datas about small and medium enterprises are not easy to obtain, so the inference is less general conclusion.In addition, the study of policy tools about tax rate are mostly theoretical analysis or personal empirical researches, therefore the conclusion of income tax rate to the company under-reported behaviors is not consistent.This study uses Taiwan’s business income tax returns data from 2009 to 2010 and estimates the effect of corporate income tax rate on corporate tax avoidance.Considering that endogenous relationship between the policy of the company and the tax rate, we use the two-stage least squares method with instrumental variable to get over the endogeneity bias.Finally, the results indicate that when the corporate income tax rate decreases by 1%, the under-reported income tax will be reduced by 1.03%. Therefore, the decline of under-reported behavior by company can not only make up for the loss of tax rate, but also reduce the distribution of the national taxation bureau in the audit resources and improve the efficiency of collection.