囤房稅能降低房價所得比嗎？合成控制法的應用

Can Vacant House Tax Policy Affect Housing Price-Income Ratio? A Synthetic Control Method Approach

2014年6月財政部修正房屋稅條例後，將住家用之非自住稅率由1.2%~2%提高為1.5%~3.6%，並授權地方政府得視所有權人持有房屋戶數訂定差別稅率。桃園市、宜蘭縣等縣市政府亦因此提出各自之囤房稅政策，以求提高房屋持有成本，藉此抑制房價、避免囤房，達成健全房市、落實居住正義之目標。本文整理臺灣地區自2002年至2018年止共17年各縣市之資料，並採用合成控制法（synthetic control method）去模擬合成臺北市、桃園市及宜蘭縣於實施囤房稅政策期間內，若無實施囤房稅政策之反事實數據，再與現實中受囤房稅政策影響之實際數據做分析比較，結果發現桃園市採提高單一稅率方式具有顯著抑制房價效果，而臺北市及宜蘭縣雖均依持有住家用之非自住房屋戶數訂定差別稅率，但仍因兩者政策力道不同，臺北市有明顯抑制房價所得比效果，然而宜蘭縣則疑似力道偏弱而無顯著效果。最後，本文之研究發現可提供各縣市政府於決定囤房稅政策時參考。

In June 2014, the Ministry of Finance amended the Regulations on Housing tax, raising the non-owner-occupied tax rate for residential purposes from 1.2%-2% to 1.5%-3.6%, and authorized local governments to set differential tax rates according to the number of houses held by owners. Therefore, the municipal governments of Taipei City, Taoyuan City, Yilan County and other counties also put forward their own policies on vacant house tax in order to raise the housing holding cost, so as to curb housing prices, avoid housing hoarding, and achieve the goal of perfecting the housing market and implementing housing justice. This paper collates the data of counties and cities in Taiwan for 17 years from 2002 to 2018. The synthetic control method is used to simulate and synthesize the counterfactual data of Taipei City, Taoyuan City and Yilan County during the implementation of the vacant house tax policy. And then make analysis and comparison with the actual data affected by the policy of vacant house tax.
Our results show that the single tax rate increase in Taoyuan City has a significant effect on inhibiting the ratio of housing price to income, while Taipei City and Yilan County set the differential tax rate according to the number of households with non-owner-occupied housing. However, due to their different policy forces, Taipei City has a significant effect on inhibiting the ratio of housing price to income, while Yilan County has a suspected weak force and no significant effect. Finally, the findings of this paper can be used as a reference for municipal governments to decide the policy of vacant house tax.