抑制我国房地产市场过度投机的政策研究

房价的过快上涨引起了社会的普遍关注,如何抑制房价的过度波动成为政府管理的重要目标。从中国房价的实际来看,很多研究者认为是投机推动了房价的较大波动。中国房价的上涨已经无法用价值规律和其他经济学原理来加以解释,很多城市的房价收入比和房屋租售比远远超过国际警戒线,如此离谱的涨幅背后,房地产投机炒作行为功不可没,抑制投机成为关键的手段。利用有关模型,本文分析了投机动力的产生机理,并且研究了房地产市场中过度投机产生的原因,包括投机的进入门槛低,地方政府、住宅房产的特性和不完善的租赁市场等对投机的影响等。根据这些诱因,从防止出现金融危机和削弱投机动力降低投机预期收益的角度,可能的政策组合包括建立和完善保降性住房政策、改革政绩考核指标、完善税制结构、取消预售制度或建立预售款第三方托管制度和完善租赁市场等。     

The impact of speculation on house prices in the United Kingdom

When house prices are expected to rise, the representative house mover has an incentive to secure his purchase price (i.e. exchange contracts) on the ‘new’ house before exchanging contracts on the sale price on his ‘old’ house. If all house-movers adopt this stance, the imbalance between buyers and sellers causes a self-fulfilling speculative price bubble. Transactions costs do not represent a barrier to such speculation in the house market, as such costs can be considered as being sunk costs for first-time buyers and owner-occupiers intending to move for non-speculative reasons. This idea is formalised and empirical evidence is presented which suggests that speculation is a significant determinant of house prices in the United Kingdom.     

Financialization of food. Modelling the time-varying relation between agricultural prices and stock market dynamics

This article studies the correlation of agricultural prices with stock market dynamics. We discuss the possible role of financial and macroeconomic factors in driving this time-varying relation, with the aim of understanding what caused positive correlation between agricultural commodities and stocks in recent years. While previous works on commodity-equity correlation have focused on broad commodity indices, we study 16 agricultural prices, in order to assess patterns that are specific to agricultural commodities but also differences across markets. We show that an explanation based on a combination of financialization and financial crisis is consistent with the empirical evidence in most markets, while global demand factors don’t appear to play a significant role. The correlation between agricultural prices and stock market returns tends to increase during periods of financial turmoil. The impact of financial turmoil on the correlation gets stronger as the share of financial investors in agricultural derivatives markets rises. Our findings suggest that the influence of financial shocks on agricultural prices should decrease as global financial tensions settle down but also that, as long as agricultural markets are ‘financialized’, it might rise again when it is less needed, i.e. in the presence of new financial turmoil.     

Hedging,selective hedging,or speculation? Evidence of the use of derivatives by Brazilian firms during the financial crisis

This paper analyse the use of foreign exchange derivatives by non-financial publicly traded Brazilian companies from 2007 to 2009. Using balance-sheet data on firms’ positions in derivatives and their foreign exchange exposure, the paper verifies the existence of three groups of derivative users: hedgers, selective hedgers – companies that significantly changed the volume of derivatives used during this period, but used them in line with their currency exposure – and active speculators – companies that adopted positions that would have been inadvisable had the aim been to hedge their currency exposure. Selective hedgers and speculators have one similarity: both tried to obtain gains through the continuous process of domestic currency appreciation. Confirming the optimal hedging literature, the paper shows that several firm characteristics are able to explain the use of derivatives and hedging by firms but market timing in the derivative markets is explained solely by firms’ foreign exposure, corporate governance and the macroeconomic environment.     

Informational efficiency: ranking markets

Summary. The paper studies informational properties of three types of imperfectly competitive markets: a one-signal speculative market (OSS market) in which agents have only private information about the fundamental value (v) of the risky asset traded, a two-signal speculative market (TSS market) in which agents have private information about both v and the asset supply, and a market in which agents are endowed with both information about v and shares of the risky asset traded. In this last market (JA market), agents have joint activities: they trade for both speculative and hedging purposes. It is shown that (i) the JA market and the OSS market are the most and the least efficient, respectively, and (ii) the levels of informational efficiency in the three markets are inversely correlated with the intensities with which traders use their private information about the fundamental value of the asset. Received May 28, 1999; revised version: May 28, 1999     

How financial investment distorts food prices: evidence from U.S. grain markets

Convergence between commodity futures prices and the underlying physical assets at each contract's expiration date is a pivotal condition for the market's functioning. Between 2005 and 2010, convergence failed for several U.S. grain markets. This article presents a price pressure‐augmented commodity storage model that links the scale of nonconvergence to financial investment channeled through indices, which are traded in commodity futures markets. The model is empirically tested, using Markov regime‐switching regression analysis. Regression results strongly support the model's predicted link between index investment and the extent of nonconvergence for three grains traded at the Chicago Board of Trade: wheat, corn, and soybeans.     

Devaluation without common knowledge

In an economy with a fixed exchange rate regime that suffers a random adverse shock, we study the strategies of imperfectly and sequentially informed speculators that may trigger an endogenous devaluation before it occurs exogenously. The game played by the speculators has a unique symmetric Nash equilibrium which is a strongly rational expectation equilibrium in the set of all strategies with delay. Uncertainty about the extent to which the Central Bank is ready to defend the peg extends the ex ante mean delay between the exogenous shock and the devaluation. We determine endogenously the rate of devaluation.     

A roller coaster ride: an empirical investigation of the main drivers of the international wheat price

Over the last decade, commodity prices have registered substantial booms and busts marked by extreme volatility. Wheat in particular, one of the main nonoil commodities, has registered a roller coaster in price levels which seems to be inconsistent with supply and demand fundamentals. To acutely investigate the drivers of wheat prices and quantify their impact, a vector error correction model (VECM) has been used. The exogenous variables have been distinguished into four groups: market‐specific factors, broad macroeconomic determinants, speculative components, and weather variables. The quadriangulation of the determinants will enable us to better understand the movements in wheat price and identify the specific role of each component. The results show that a mix of factors are contributing to wheat price movements, including speculation, global demand, and real effective exchange rate.