以財稅資料分析台灣不動產稅制公平性

PROPERTY TAXATION IN TAIWAN: AN EMPIRICAL ANALYSIS OF EQUALITY WITH ADMINISTRATIVE TAX DATA

本文使用財政部財稅資料庫2004至2017年之個人資料檔、所得明細檔、財產登錄檔等資料，分析我國不動產交易價值、課稅價值與持有人所得、財富之關係，並探討現有不動產持有稅制之公平性。研究結果顯示現行稅制長期低估不動產課稅現值，且偏離市場價值之現象在高價值物件更為明顯。因此，我國的不動產估價比率（assessment-sales ratio）雖在持有人所得上具微幅累進性，但在資產價值上卻呈現明顯的累退性，即資產價值較高者在持有不動產時，反而享有更多因課稅現值偏低而產生的租稅優惠。我們也發現估價比率對資產價值的累退性僅限於不動產，對不動產持有人之金融資產或間接持有之資產反而具有累進性，這意味著現有稅制較有利將資產配置集中於不動產。我們認為若能縮小課稅現值與市場價值之差距，將能強化稅制公平性並降低經濟效率損失。

We use income tax and wealth data from Taiwan’s Ministry of Finance, from 2004 to 2017, to investigate the incidence of property taxation. Specifically, we focus on the relationships among a property’s market value, its assessed value, and the owner’s income and wealth. Our results show that Taiwan’s property tax system consistently undervalues real estate. The gap between assessed value and market value is especially prominent among high-value properties. As a result, while the assessment-sales ratio is weakly progressive regarding income, it is severely regressive regarding wealth. In addition, since this regressiveness is not evident for financial and other non-property assets, the property tax system provides incentives for people to concentrate their assets on real estate. Closing the gap between property’s assessed and market values would enhance the equity of the tax system and reduce resource allocation distortions.