Uniqueness of asset prices in an exchange economy with unbounded utility

Summary. This paper studies conditions under which the price of an asset is uniquely determined by its fundamental value – i.e., no bubbles can arise – in Lucas-type asset pricing models with unbounded utility. After discussing Gilles and LeRoy's (1992) example, we construct an example of a two-period, representative agent economy to demonstrate that bubbles can arise in a standard model if utility is unbounded below, in which case the stochastic Euler equation may be violated. In an infinite horizon framework, we show that bubbles cannot arise if the optimal sequence of asset holdings can be lowered uniformly without incurring an infinite utility loss. Using this result, we develop conditions for the nonexistence of bubbles. The conditions depend exclusively on the asymptotic behavior of marginal utility at zero and infinity. They are satisfied by many unbounded utility functions, including the entire CRRA (constant relative risk aversion) class. The Appendix provides a complete market version of our two-period example. Received: January 22, 1996; revised version: February 18, 1997     

房地产泡沫问题研究

自1998年开始，我国住房制度改革逐步深入，特别是随着福利化分房的结束，住房商品化的开始，房地产业进入了持续快速发展的新时期。山东省房地产产业发展迅速，成为影响GDP增长的重要因素。但与此同时，房地产价格也连续快速攀升。本论文以济南市为例，在收集整理大量有关房地产泡沫资料的基础上，得出了自己对于济南房地产市场的判断：总体发展健康，但同时需要进一步加强防范措施避免泡沫的形成。     

Information and adjustment in a local housing market

Existing studies on bubbles have been mainly concerned with investigating the stationarity properties of stock prices and market fundamentals. We develop a new method of testing for bubbles that relates the bubble component of stock prices to the probability of bursting in the context of the Weibull distribution. There were several eruptions and subsequent collapses of seeming bubbles over the past three decades: 1987 (Black Monday), 2000 (information technology (IT) boom) and 2007 (housing market boom). Using US monthly data for the S&P 500 and NASDAQ series, we have found that the S&P 500 series contained an explosive bubble only during the boom of the housing market that occurred before the 2007 global economic crisis, and the NASDAQ market contained an explosive bubble during the surge of stock prices peaking in 1987 and 2007, although our stationarity tests fail to detect the bubbles. No bubble was found in both the S&P and NASDAQ series during the 2000 IT boom. Our evidence corroborates the criticism that the traditional unit root and cointegration tests may not be able to detect some important class of bubbles.     

INEFFICIENT INFORMATION AGGREGATION AS A SOURCE OF ASSET PRICE BUBBLES

This paper presents a new theory of bubbles, or discrepancies between the market clearing price and the fundamental value of an asset. In our setting, Bayesian traders, oriented towards long-term gains, receive private information ('news') and also make inferences from noisy price signals. Price exhibits higher variance than fundamental value (the latter defined as fully-aggregated expected value) especially when news is informative but infrequent. The corresponding bubbles are self-limiting but may exhibit momentum and overshooting. A parametric example, involving the exponential/gamma conjugate families, is provided.
We don't have any penetrating explanations of yesterday's stock market, but we certainly believe that stocks do not fall 86½ points for nothing.
The general case for a drop in the market after its recent record highs is clear enough. The Fed…,… the tax bill.
None of this, though, was any different on Thursday than it was with the market at its peak six sessions ago. News…and rumors yesterday…were certainly negative but scarcely dramatic.
Some market pros believe this kind of a drop is merely the market catching up with what it already knew. We doubt it. Our hunch is that something changed between Wednesday and Thursday, and that eventually we'll learn what it was ( Wall Street Journal Editorial, Friday, September 12, 1986).     

Depth of knowledge and the effect of higher order uncertainty

Summary A number of recent papers have highlighted the importance of uncertainty about others' information in models of asymmetric information. We introduce a notion that reflects the depth of knowledge in an information system. We show how the depth of knowledge can be used to bound the effect of higher order uncertainty in certain problems. We further provide bounds on the size of bubbles in finite horizon rational expectations models where the bounds depend on the depth of knowledge.We thank Dov Samet for pointing out an error in an earlier version.     

Some properties of periodically collapsing bubbles

This paper explores some properties of periodically collapsing bubbles, which are a very popular model in the bubbles literature. We first demonstrate that complicated nonlinear bubbles can be represented as a time-varying parameter linear model of order 1. We demonstrate that the bubbles are explosive and nonstationary. We also derive conditions under which the bubbles are strictly stationary. We also demonstrate that the bubbles cannot be weakly stationary by deriving the tail indices of the strictly stationary distribution.     

Can Markets Learn to Avoid Bubbles?

One of the most striking results in experimental economics is the ease with which market bubbles form in a laboratory setting and the difficulty of preventing them. This article re-examines bubble experiments in light of the results of an earlier series of market experiments that show how learning occurs in markets characterized by an asymmetry of information between buyers and sellers, such as found in Akerlof's lemons model and Spence's signaling model. Markets with asymmetric information are incomplete because they lack markets for specific levels of product quality. Such markets either lump all qualities together (lemons) or using external indications of quality to separate them (signaling). Similarly, the markets used in bubble experiments are incomplete in that they are lacking a complete set of forward or futures markets, depriving traders of the information supplied by the prices in those markets. Preliminary experimental results suggest that the addition of a single forward market can sometimes mitigate bubble formation and this article suggests more extensive research in this direction is warranted. Market bubbles outside of the laboratory usually are found in markets in which forward and futures markets are either legally restricted or otherwise limited. Experimentation in markets with asymmetric information also indicates that the ability of subjects to learn how to send and receive signals can be enhanced by changing the way that market information is presented to them. We explore how this result might be used to help asset markets learn to avoid bubbles     

Determinants of stock price bubbles

In this paper we propose a cross-sectional model of the determinants of asset price bubbles. Using 589 firms listed on the NYSE, we find conclusive evidence that trading volume and share price volatility have statistically significant effects on asset price bubbles. However, evidence from sector-based stocks is mixed. We find that for firms belonging to electricity, energy, financial, and banking sectors, and for the smallest size firms, trading volume has a statistically significant and positive effect on bubbles. We do not discover any robust evidence of a statistically significant effect of share price volatility on bubbles at the sector-level.     

信息不对称资本市场的实验研究

我们采用经济学实验研究方法构建了信息不对称的实验室资本市场,研究信息是否可以通过市场迅速传递。实验结果表明,在信息不对称的情况下,资本市场是非有效的;市场对信息的传递和价格反应是有条件的而且也是需要时间的;资本市场中的投资者并非完全理性,而是具有认知和行为偏差的普通人,存在过度自信和过度交易的情况;信息不对称还可能引起市场操纵行为,从而导致价格泡沫的形成。     

Modelling the housing market in OECD countries

Recent episodes of housing bubbles, which occurred in several economies after the burst of the United States housing market, suggest studying the evolution of housing prices from a global perspective. We utilise a theoretical model for the purposes of this contribution, which identifies the main drivers of housing price appreciation, such as, for example, income, residential investment, financial elements, fiscal policy and demographics. In a second stage of our analysis, we test our theoretical hypothesis by means of a sample of 18 OECD countries from 1970 to 2011. We employ the vector error correction econometric technique in terms of our empirical analysis, which permits us to model the long-run equilibrium relationship and the short-run dynamics, which also helps to account for endogeneity and reverse causality problems.     

PRODUCE OR SPECULATE? ASSET BUBBLES,OCCUPATIONAL CHOICE,AND EFFICIENCY*

We study the effects of rational asset bubbles in an overlapping‐generations economy where asset trading requires specialized intermediaries and agents freely choose between working in the production or the financial sector. Frictions in the market for deposits create rents in the financial sector that affect agents’ occupational choices. When rents are large, the private gains associated with trading bubbles lead too many agents to become speculators, causing bubbles to lose their efficiency properties. Moreover, if speculation can be carried out by skilled labor only, then bubbles displace skilled workers away from the productive sector and raise income inequalities.     

Tournament incentives and asset price bubbles: Evidence from a field experiment

In this note we show at the example of an experimental stock market, conducted on the occasion of the World Soccer Championship 2010 in South Africa, how tournament incentives might contribute to the formation of asset price bubbles.     

Bubbles in US regional house prices: evidence from house price–income ratios at the State level

We investigate the presence of bubbles in the US house price-income ratio at the State level by applying the recent time series-based econometric test to data from January 1975 to December 2014. We find evidence of bubbles in several States in the 1980s (i.e. California, Hawaii, Massachusetts, New York, etc.), which coincides with some existing studies that investigate housing bubbles or booms and busts using a range of alternative approaches. Our results show the existence of a housing bubble that originates in the early 2000s and collapses in the mid-2000s in more than 20 States and the District of Columbia concluding that the bubbles of the 2000s were more widespread than the 1980s, which is of special interest and importance. Our results seem to be in agreement with the talk given by Alan Greenspan in 2005, who suggest no sign of a nationwide housing bubble but a lot of local bubbles. We also study the importance of the regression model specification with/without an intercept and the regression model with an intercept could lead to false-positive identification of bubbles.     

Investor sentiment,information and asset pricing model

We present an asset pricing model with investor sentiment and information, which shows that the investor sentiment has a systematic and significant impact on the asset price. The equilibrium price's rational term drives the asset price to the rational, and the sentiment term leads to the asset price deviating from it. In our model, the proportion of sentiment investors and the information quality could amplify the sentiment shock on the asset price. Finally, the information is fully incorporated into prices when sentiment investors learn from prices. The model could offer a partial explanation of some financial anomalies: price bubbles, high volatility, asset prices' momentum effect and reversal effect.     

On the Linkages of the Stock Markets of the NAFTA Countries: Fundamentals or Speculative Bubbles?

We analyze whether the linkages between the stock markets of the NAFTA member countries (Canada, Mexico, and the United States) reflect movements in fundamentals or speculative bubbles. To this end, we estimate a state-space model to decompose the stock market indexes of the three NAFTA member countries into fundamentals and speculative bubbles. We analyze the linkages of the three stock markets by means of cointegration techniques. Evidence of cointegration linkages between fundamentals is stronger than evidence of cointegration linkages between speculative bubbles.     

中国股市的理性泡沫

传统理论通常把证券市场的泡沫与投资者的非理性行为混为一谈。近期的研究却表明在一个完全理性的市场中 ,泡沫依然可以出现。本文首先对我国证券市场存在理性泡沫的可能性提出多种理论解释 ,认为下列原因导致了我国证券市场泡沫的存在 :( 1 )上市审批制 ;( 2 )可供投资的证券种类少 ;( 3 )政府的托市行为 ;( 4)卖空机制的缺乏 ;( 5)套利机制缺乏有效性 ;( 6)上市公司很少分红 ,投资者买卖股票只是为了获得买卖差价。其次 ,我们通过分析所得的结果 ,提出应对理性泡沫的政策措施。     

Two-period trading sentiment asset pricing model with information

We present a dynamic asset pricing model with investor sentiment and information, which shows that the investor sentiment plays a systematic and important role in the asset prices and the information is gradually incorporated into prices. The model has an analytical solution to the sentiment equilibrium price. We find that sentiment trading quantity not only increases the market liquidity, but also causes the asset prices' overreaction if the intensity of sentiment demand is more than a constant value. Therefore, the continuing overreactions result in a short-term momentum and a long-term reversal. The model could offer a partial explanation to some financial anomalies such as price bubbles, high volatility, asset prices' overreaction and so on.     

Bubbles as payoffs at infinity

Summary We define rational bubbles to be securities with payoffs occurring in the infinitely distant future and investigate the behavior of bubbles values. We extend our analysis to a setting of uncertainty. In an infinite horizon arbitrage-free model of asset prices, we interpret the money market account as the value of a particular bubble; a similar interpretation holds for other assets related to the state-price deflator and to payoffs on bonds maturing in the distant future. We present three applications of this characterization of bubbles.This paper was circulated under the title Stochastic bubbles in Markov economies. We acknowledge with gratitude numerous conversations with Mark Fisher, the editorial advice of David Levine and the useful comments of anonymous referees. This paper should not be interpreted as reflecting the views of the Board of Governors of the Federal Reserve System or its staff.     

Asset price bubbles in Arrow-Debreu and sequential equilibrium

Summary. Price bubbles in an Arrow-Debreu equilibrium in an infinite-time economy are a manifestation of lack of countable additivity of valuation of assets. In contrast, the known examples of price bubbles in a sequential equilibrium in infinite time cannot be attributed to the lack of countable additivity of valuation. In this paper we develop a theory of valuation of assets in sequential markets (with no uncertainty) and study the nature of price bubbles in light of this theory. We define a payoff pricing operator that maps a sequence of payoffs to the minimum cost of an asset holding strategy that generates it. We show that the payoff pricing functional is linear and countably additive on the set of positive payoffs if and only if there is no Ponzi scheme, provided that there is no restriction on long positions in the assets. In the known examples of equilibrium price bubbles in sequential markets valuation is linear and countably additive. The presence of a price bubble means that the dividends of an asset can be purchased in sequential markets at a cost lower than the asset's price. We present further examples of equilibrium price bubbles in which valuation is nonlinear, or linear but not countably additive.     

FUTURES MARKETS AND BUBBLE FORMATION IN EXPERIMENTAL ASSET MARKETS*

Abstract. We construct asset markets of the type studied in Smith et al. (1988) , in which price bubbles and crashes are widely observed. In addition to a spot market, there are futures markets in operation, one maturing at the beginning of each period of the life of the asset. We find that when futures markets are present, bubbles do not occur in the spot markets. The futures markets seem to reduce the speculation and the decision errors that appear to give rise to price bubbles in experimental asset markets.