电子商务市场价格离散度的收敛分析

本文运用信息不对称理论和随机鞅理论分别从基于可得信息集和完全信息集这两个角度深入地探讨了资本市场的信息有效性与资源配置最优性和次优性。在理性预期和交易成本为零的假定下,其基本结论有四:一是资本市场(条件)有效等价于事后帕累托最优,资本市场完全有效等价于事前帕累托最优;二是资本市场事后帕累托最优的充要条件是信息强对称;三是资本市场事前帕累托最优的充要条件是信息强对称和信息强完全;四是不满足信息强对称的资本市场一般只能实现事后帕累托次优,而不同时满足信息强对称和信息强完全的资本市场一般只能实现事前帕累托次优。最后,根据上述观点提出了实现资本市场完全有效或事前帕累托最优的对策建议。     

价格信息成本与价格离中现象

该文在Varian(1980)中引入消费者价格信息成本和信息成本的分布,采用Janssen和Moraga(2000)的对称混合策略均衡定义,同时内生化了消费者的信息行为和厂商的定价行为,确定了Varian(1980)中的知情消费者比例,证明了厂商定价正期望利润均衡的存在性.该文证明了,在不完全价格信息条件下,市场普遍存在知情消费者,从而该文加强了Varian(1980)的结论.     

INCOME DISPERSION AND PRICE DISCRIMINATION

Abstract.  This paper analyses the effects of inter-market and intra-market income heterogeneities on output and social welfare under uniform pricing and differential pricing regimes by considering a finite number of markets. We first derive the linear demand curve in each market under plausible conditions, and then show that more markets (and consumers) are excluded under uniform pricing the higher are the inter-market income differences. We also show that adding markets, even of lower income levels than those of existing markets, helps to decrease prices and thus cause more markets to be served. Implications of intra-market income dispersion are also explored.     

THE MORPHOLOGY OF PRICE DISPERSION

This article is a study of the shape and structure of the distribution of prices at which an identical good is sold in a given market and time period. We find that the typical price distribution is symmetric and leptokurtic, with a standard deviation between 19% and 36%. Only 10% of the variance of prices is due to variation in the expensiveness of the stores at which a good is sold, whereas the remaining 90% is due, in approximately equal parts, to differences in the average price of a good across equally expensive stores and to differences in the price of a good across transactions at the same store. We show that the distribution of prices that households pay for the same bundle of goods is approximately Normal, with a standard deviation between 9% and 14%. Half of this dispersion is due to differences in the expensiveness of the stores where households shop, whereas the other half is mostly due to differences in households' choices of which goods to purchase at which stores. We find that households with fewer employed members pay lower prices and do so by visiting a larger number of stores instead of by shopping more frequently.     

HOUSING PRICE AND FUNDAMENTALS IN A TRANSITION ECONOMY: THE CASE OF THE BEIJING MARKET

This article develops a dynamic rational expectations general equilibrium framework that links house value to fundamental economic variables such as income growth, demographics, migration, and land supply. Our framework handles nonstationary dynamics as well as structural changes in fundamentals that are commonplace in transition economies. Applying the framework to Beijing, we find that the equilibrium house price and rent under reasonable parameterizations of the model are substantially lower than the data. We explore potential explanations for the discrepancies between the model and the data.     

中国权证市场高频数据波动特征及其原因分析

权证市场价格的异常波动是投资者和管理层热切关注的问题。研究表明,中国权证市场的价格波动呈现出尖峰厚尾、持久记忆、波动集群的波动特征;而投资者的损失厌恶心理是导致这种异常波动的重要原因。因此,为了减少投资者的投资风险,需要对投资者进行引导教育,同时,完善证券市场的信息披露制度,加强市场监管。     

实验市场中的价格预期

采用4个变化的口头双向拍卖模拟市场(2个先稳定后通胀,2个先通胀后稳定),本研究发现通胀市场中的预期与理性预期假设吻合良好,同时通货预期不受通胀率的影响.相反稳定市场不支持理性预期模型.结合Williams(1987)的研究结果,本研究提示市场设置是影响稳定市场和通胀市场表现差异的主要原因.     

实验市场中的价格预期

采用4个变化的口头双向拍卖模拟市场(2个先稳定后通胀,2个先通胀后稳定),本研究发现通胀市场中的预期与理性预期假设吻合良好,同时通货预期不受通胀率的影响。相反稳定市场不支持理性预期模型。结合Williams(1987)的研究结果,本研究提示市场设置是影响稳定市场和通胀市场表现差异的主要原因。     

INFORMATION AND PRICE DISPERSION: THEORY AND EVIDENCE

Limited information is the key element generating price dispersion in models of homogeneous-goods markets. We show that the global relationship between information and price dispersion is an inverse-U shape. We test this mechanism for the retail gasoline market using a new measure of information based on commuter data from Austria. Commuters sample gasoline prices on their commuting route, providing us with spatial variation in the share of informed consumers. Our empirical estimates are in line with the theoretical predictions. We also quantify how information affects average prices paid and the distribution of surplus in the gasoline market.     

北京市外来人口空间集聚特点,形成机制及其调控对策

外来人口冲击大城市是我国现阶段大城市发展遇到的难题．也是迫切需要解决的问题。本文从宏观分析和微观调查相结合的角度．探讨了北京市外来人口空间集聚的特点、形成机制及其对城市发展的影响．并提出了相应的调控对策思路，     

ESTIMATES OF THE PRICE ELASTICITY OF SWITCHING BETWEEN BRANDED AND GENERIC DRUGS

We estimate price elasticities of switching from branded to generic drugs for two widely used drugs: Prozac and Zocor. We find the price elasticity of switching varies by drug and is between 0.01 and 0.10. While elasticity estimates for Zocor are robust to the inclusion of controls for supply‐side factors, those for Prozac are not. Our results indicate consumers in managed care plans are most responsive to differences in out‐of‐pocket (OOP) cost, and we estimate that a 10% increase in the OOP cost difference between Zocor and generic Simvastatin increases an individual's probability of switching to the generic by approximately 0.3%. This would result in a modest total savings of $36,700 among our sample of 114,218 privately insured Zocor users. Our finding that individuals are relatively unresponsive to the lower prices caused by generic introduction implies that policies targeting supply‐side behavior are likely to have a larger effect on generic uptake than price‐based inducements. If generic‐uptake did occur immediately within the first 18 months after generic introduction, the total savings among individuals and insurance companies within our sample would be approximately $7 million for Zocor and $255,000 for Prozac. (JEL I11, I18)     

PRICE DISPERSION,INFLATION, AND WELFARE*

We examine the implications of inflation for both price dispersion and welfare in a monetary search economy. In our economy, if the degree of buyers' incomplete information about prices is fixed, both price dispersion and real prices are increasing in inflation. As the inflation rate approaches the Friedman rule, both price dispersion and welfare losses vanish. If households choose the number of prices to observe, then the optimal inflation rate may exceed the Friedman rule as inflation induces search and, up to a point, raises welfare by eroding market power.     

CONSUMER SEARCH,PRICE DISPERSION,AND INTERNATIONAL RELATIVE PRICE FLUCTUATIONS*

This article develops a model of consumer search consistent with the evidence of substantial price dispersion and time spent shopping within countries to study international deviations from the law of one price (LOP) and relative price fluctuations. Search frictions lead firms to price discriminate across markets based on the opportunity cost of search, which depends on the local wage. With productivity and taste shocks estimated from the data, deviations from the LOP are as volatile and persistent as in the data. Fluctuations in relative wages, real exchange rates, and the terms of trade are also consistent with the data.     

THE PERFORMANCE AND LONG-RUN CHARACTERISTICS OF THE CHINESE IPO MARKET

Abstract.  We study the short-run and long-run performance of 340 and 409 IPOs, respectively, listed on China's two exchanges from 1996 to 1997. We find that the average underpricing is 127.3%, and that the average market-adjusted cumulative return and buy-and-hold return over the three years after listing are 10.3% and 10.7%, respectively, which are both significantly positive at the 5% level. We then use a cross-sectional analysis to explain the long-run out-performance of Chinese IPOs, and find that firms with lower government ownership, smaller offering sizes, high-tech features and lower initial returns perform better in the long-run.     

OIL PRICE SHOCKS AND STOCK MARKET BOOMS IN AN OIL EXPORTING COUNTRY

This paper analyses the effects of oil price shocks on stock returns in Norway, an oil-exporting country, highlighting the transmission channels of oil prices for macroeconomic behaviour. To capture the interaction between the different variables, stock returns are incorporated into a structural VAR model. I find that following a 10% increase in oil prices, stock returns increase by 2.5%, after which the effect gradually dies out. The results are robust to different (linear and non-linear) transformations of oil prices. The effects on the other variables are more modest. However, all variables indicate that the Norwegian economy responds to higher oil prices by increasing aggregate wealth and demand. The results also emphasize the role of other shocks; monetary policy shocks in particular, as important driving forces behind stock price variability in the short term.     

SPINOFFS AND THE MARKET FOR IDEAS*

We present a theory of entry through spinoffs where workers generate ideas and possess private information concerning their quality. Because quality is privately observed, adverse selection implies that the market can only offer a price that reflects the average quality of ideas sold. Only workers with good ideas decide to spin off, whereas workers with mediocre ideas sell them. Existing firms pay a price for ideas sold in the market that implies zero expected profits. Hence, firms’ project selection is independent of firm size, which can lead to scale‐independent growth. This mechanism results in invariant firm‐size distributions that resemble the data.     

THE MEASUREMENT OF POVERTY WITH GEOGRAPHICAL AND INTERTEMPORAL PRICE DISPERSION: EVIDENCE FROM RWANDA

It is not known to what extent welfare measures result from seasonal and geographical price differences rather than from differences in living standards across households. Using data from Rwanda in 1983, we show that the change in mean living standard indicators caused by local and seasonal price deflation is moderately significant at every quarter. By contrast, the differences in poverty measures caused by this deflation can be considerable, for chronic as well as transient or seasonal poverty indicators. Thus, poverty monitoring and anti-poverty targeting can be badly affected by inaccurate deflation of living standard data. Moreover, when measuring seasonal poverty, the deflation based on regional prices instead of local prices only partially corrects for spatial price dispersion. Using annual local prices instead of quarterly local prices only yields a partial deflation, which distorts the measure of poverty fluctuations across seasons and biases estimates of annual and chronic poverty.