公司層級隱租稅與賦稅改革

THE EXTENT OF IMPLICIT TAX AT THE CORPORATE LEVEL AND TAX REFORM

本文探討台灣2010年稅制改革對企業隱租稅(implicit tax)的影響。過去文獻多以企業繳納給政府的顯租稅(explicit tax)衡量企業租稅負擔，常忽略享有出稅優惠之企業降低稅前報酬率的隱租稅。 本文採台灣上市櫃公司1999–2017年度資料，同時採間接法與直接法分析。實證結果顯示，首先，稅前報酬率與有效稅率呈正向關係，顯示租稅優惠產生隱租；其次，2010年稅改後，整體企業的隱租稅降低；第三，高科技產業的隱租稅在稅改後顯著降低，符合隱租稅理論預期；第四，稅改後傳統產業的隱租稅，直接法沒有顯著變化，符合預期；第五，直接法發現稅改前高科技產業的隱租稅顯著高於傳統產業，符合高科技產業享有較多租稅優惠；稅改後隱租稅差異縮小，達成2010稅改的政策目的。

This study explores whether Taiwan’s Tax Reform Act of 2010 (TRA2010) affected implicit corporate taxes. The literature mostly uses explicit taxes paid to the government to measure tax burden, whereas the implicit tax, the reduced pre-tax rate of return for enterprises enjoying tax preferences, is often neglected. Applying both direct and indirect methods, this study uses data from TSEC- and OTC-listed companies from 1999 to 2017. Several results emerge: first, pre-tax rate of return is positively related to effective tax rates, indicating that tax preferences induce the implicit tax; second, the implicit tax decreased across industries, especially for high-tech industries, after TRA2010; third, under the direct method, the implicit tax of traditional industries does not show significant difference after TRA2010; and fourth, under the direct method, the implicit tax of high-tech industries is significantly higher than that of traditional industries. Taken together, the results demonstrate that high-tech corporations enjoyed more tax preferences before TRA2010, and that the differences in the implicit tax between the two industries narrowed after TRA2010. Hence, the purpose of TRA2010, to decrease variation in tax preferences across industries, was achieved.