REAL ESTATE MARKET OF A BRAZILIAN METROPOLIS: SUSTAINED GROWTH OR SPECULATIVE BUBBLE?

ABSTRACT Purpose: To analyze the real estate sector of a Brazilian metropolis in the recent period of great valuation of the asset in the country and to investigate if there are signs of a speculative bubble in this market. Originality/gap/relevance/implications: This article presents a version of the Case-Shiller Index, which describes the evolution of the relationship between house prices and rental prices and uses models in order to identify if the rise in property prices rests on good economic fundamentals. Key methodological aspects: The approach is quantitative and involves the construction of the price-rent index, unit root test with an instrument that allows structural break with trend (Innovation Outlier Model) and analysis of cointegration using estimates of a Vector Error Correction Model (VECM). Summary of the results: The results do not favor the interpretation that the real estate market rests on solid economic fundamentals. On the contrary, the evolution of the price-rent index and the lack of causal relationship of rents to prices towards long-term equilibrium are suggestive of the existence of a speculative bubble. Key considerations/conclusions: The results support authors who are critical to the efficient market hypothesis (EMH) and suggest that the relative increase in property prices stems only from the belief that their selling price will be higher in the future. It is therefore foreseeable a decrease of real prices of housings, with equity losses for the participants in that market.

【摘要】
研究目的：针对巴西某大都市房地产板块在该国近期资产大幅升值周期内的表现展开分析，并探究该市场是否存在投机泡沫（speculative bubble）相关迹象。
原创性/研究缺口/研究价值/研究意义：本文提出了一种凯斯-席勒指数（Case-Shiller Index）变体，该指数可刻画房价与租金的关系演变，并通过模型识别房价上涨是否依托稳健的经济基本面。
核心方法论层面：本研究采用定量研究方法，具体包括构建房价-租金比指数、采用允许带趋势结构突变的检验工具——创新异常值模型（Innovation Outlier Model）——开展单位根检验（unit root test），以及借助向量误差修正模型（Vector Error Correction Model，VECM）的估计结果开展协整分析。
研究结果概要：研究结果并不支持“房地产市场依托稳健经济基本面”这一解读。反之，房价-租金比指数的走势，以及租金与房价之间缺乏指向长期均衡的因果关系，均暗示投机泡沫的存在。
关键思考与结论：本研究结果支持那些对有效市场假说（efficient market hypothesis，EMH）持批判态度的学者的观点，表明房价的相对上涨仅源于市场参与者认为未来住房售价将更高的预期。因此可预见住房实际价格将出现下跌，该市场参与者将面临资产净值损失。