• 作者： 陳彥仲
• 作者服務機構： 國立成功大學都市計劃系
• 中文摘要： Vacant housing exists when the number of housing units exceeds the household demand. Theory suggests that an increase in owners' cost of vacant units yields a decrease in the market price. Owners of vacant units reduce prices to avoid the impact of the tax. Vacancy rates would then fall. In this study, we constructed a simultaneous model to estimate the effect of a proposed vacant housing tax on housing price. The model was constructed based on two conditions: housing market equilibrium and the balance of family income and expenditure. Housing market equilibrium is maintained so that the housing price can be obtained, which is a function of family income. The balance of family income and expenditure is also maintained so that family income can be derived as a function of house price. The uniqueness of the solution is examined according to a sufficient condition of the negative dominant diagonal (NDD), and is empirically confirmed. Several sources of reported data on the Taiwan housing market were collected and manipulated to calibrate coefficients in the structural model and to estimate the effects. The estimated results indicate that an ad valorem vacancy tax with a 1% tax rate yields a decrease in the market price of housing ranging from 2.6 to 8.8% in selected study areas.
• 英文摘要： 當市場上住宅所提供之服務無法契合家戶之住宅需求時，即產生空屋。包括新建餘屋、老舊空屋以及因遷徙、季節而存在之臨時性空屋等。從購屋動機加以區分，又可以將之區分為投資性空屋以及因消費動機而形成之自然空屋。若市場存在過高的空屋，無疑是社會資源的浪費。相關文獻研議提高空屋持有者之持有成本將可透過市場機制調節空屋率及市場價格。本研究嘗試建立理論模型以模擬對投資性空屋課征空屋稅時，市場住宅價格之變動情形。模型結構為聯立方程式，包含兩項均衡條件：住宅市場均衡以及家戶所得支出均衡。透過住宅市場均衡條件以求解住宅均衡價格，而此均衡價格將為家戶所得的函數。另外，透過家戶所得支出均衡條件，則可推論家戶之均衡所得為住宅均衡價格的函數。因而構成聯立方程式。本模型之結構式為非線性結構，本研究透過負值優勢對角線（negative dominant diagonal, NDD）之充分條件，對模型是否存在唯一解進行認定。認定結果顯示，理論模型之唯一解並不確定，但就實證資料所校估建立之實證模型則存在唯一解。本研究之實證結果推論，對投資性空屋課征每坪1%之從價稅，則研究地區之住宅價格下降約2.6% 到8.8%之間。
• 中文關鍵字： housing, vacancy rate, vacancy tax, housing price, family income, simultaneous equations, Taiwan
• 英文關鍵字： 住宅，空屋，空屋稅，住宅價格，家戶所得，聯立方程式，臺灣