Asset price volatility and trading volume with rational beliefs

Summary. This paper develops a model of speculative trading in a large economy with a continuum of investors. In our model the investors are assumed to have diverse beliefs which are rational in the sense of being compatible with observed data. We demonstrate the existence of price amplification effects and show that the equilibrium prices can be higher or lower than the rational expectation equilibrium price. It is also shown that trading volume is positively related to the directions of price changes. Moreover, we study how asset price volatility and trading volume are influenced by belief structures, short selling constraints and the amount of fund available for investment.Received: 23 January 2003, Revised: 30 April 2003, JEL Classification Numbers: D84, G12.We are grateful to Professors Mordecai Kurz, Kenneth Arrow, Kenneth Judd, Carsten Nielsen, Maurizio Motolese, Mark Garmaise, Jean-Michel Grandmont, Peter Hammond, Karl Shell, Jan Werner and participants of the Society for the Advancement of Economic Theory (SAET) Conference and Stanford Institute of Theoretical Economics (SITE) Conference for many helpful suggestions. Correspondence to: H.-M. Wu     

The option of joint purchase in vertically differentiated markets

Summary. Within the framework proposed by Mussa and Rosen (1978) for modelling quality differentiation, consumers are assumed to make mutually exclusive purchases. A unique pure strategy equilibrium exists in this case. In this note, we allow consumers to buy simultaneously different variants of the differentiated good. We call this the “joint purchase option”. The paper proposes a detailed analysis of price competition when this option is opened: first, we show that either uniqueness, or multiplicity, or absence of price equilibrium arise, depending on the utility derived from joint purchase relative to exclusive purchase. Second, we characterize these equilibria, whenever they exist. Received: July 25, 2001; revised version: October 21, 2002 RID="*" ID="*" The second author gratefully acknowledges the financial support from Interuniversity Attraction Pole Program- Belgian State- Federal Office for Scientific, Technical and Cultural Affairs under contract PAI 5/26. Correspondence to: X.Y. Wauthy     

Influence of cultural factors on price clustering and price resistance in China's stock markets

This paper builds on prior research by analysing the impact of cultural factors on both price clustering and price resistance in China's stock markets. The results support the presence of cultural factors impacting on price clustering with the digit 8 showing a higher propensity for clustering and the digits 4 and 7 showing a lower propensity in the A‐share market, where stock is denominated in renminbi and traded by mainland Chinese. These results are further supported by an analysis of the B‐share market, where cultural factors have no (or less) impact on the price of Chinese stocks traded by foreign investors in US dollars (or in Hong Kong dollars). A range of measures for price resistance show the digits 0 and 5 to be significant resistance points in the A‐share market. Although digit 8 cannot be considered as a resistance point, its resistance level is highest among the remaining numbers. In conclusion, cultural factors help to explain not only price clustering in the Chinese stock markets but price resistance levels as well, albeit at a weak level.     

中国股市开、收盘波动性的比较研究

利用EGARCH模型,对2000年1月至2007年4月间沪深两市具有代表性的股票及指数的开收盘收益率的波动性进行实证分析,结果表明收益率序列有明显的ARCH效应,其波动性具有显著的非对称性的冲击的持续性;在样本期内,上交所的个股和指数未能观察到开盘波动性高于收盘波动性的现象,而深交所个股在2006年7月实施收盘集合竞价机制之后比较明显地观察到开盘波动性高于收盘波动性的现象。     

沪深权证价格偏离分析

沪深证券市场权证理论价格与权证市场价格的偏离现象主要不是理论定价公式的输入变量误差导致的,而是因为股票收益率与权证收益率之间的相关系数与理论预期不一致,乃至相冲突所导致的。权证理论价格与市场价格偏离的主要原因是在当前的交易制度安排下,由于市场限制(摩擦)抑制了套利交易,导致权证市场投机交易占主导,以致权证市场价格偏离长期均衡水平。     

高资本充足率一定有助于银行体系稳定吗——基于房地产调控的视角

当银行面对房地产价格冲击试图保持一定的资本充足率时,较轻的冲击就可能导致银行不稳定成为一种自我实现的结果,而当银行不维持最低资本充足率时,较为严重的房地产价格下跌才有可能导致银行的不稳定,可见,高资本充足率在一定程度上反而增加了银行体系的不稳定性。在特殊情况下,适当降低银行的资本充足率或补充资本、降低法定存款准备金率等增加银行体系流动性的政策可能是有益的。     

Regulating prices for shifting between service providers

The price that a regulated access provider charges for shifting customers between service providers has significant welfare implications. Typical regulatory approaches to pricing, such as pricing based on fully allocated cost or incremental cost, ignore the characteristics of consumer demand. A theoretical alternative, Ramsey pricing, considers only the elasticity of demand for given products. This paper directs attention to the competitive process. Using US long-distance telephone services as an example, this paper shows how empirical evidence concerning customer acquisition costs, customer switching costs, and churn among service providers can help to inform price regulation.     

Using the economics of platforms to understand the broadband-based market formation in the New Zealand Ultra-Fast Broadband Network

The government of New Zealand is currently building a nation-wide fibre-optics network, a project known as the Ultra-Fast Broadband (UFB) initiative. The UFB network will cover 75 percent of New Zealanders over 10 years and will cost NZD $1.5 billion to the New Zealand government. The technical and economic characteristics of the new network will have a deep impact on the current landscape of the telecommunications markets. Institutional arrangements are in place for the development of the New Zealand's UFB: a government-owned agency, Crown Fibre Holdings (CFH); private investors who jointly with CFH own the Local Fibre Companies (LFCs) which will operate the UFB; and Retail Service Providers (RSP) that will provide end-user services by purchasing wholesale services to the LFCs. Relying on a normative economics approach that uses recent advances in the theory of platform-based markets with cross-network effects – also known as theory of two-sided platforms – the paper proposes a novel view of the way markets over the UFB will unfold. On one hand, the theory is used to explain the rationale behind regulatory decisions already made and their effect on the development of UFB-based markets for contents and services. Such analysis is followed, on the other hand, by the introduction of a simple taxonomy for the RSPs which provides the framework to argue about the most likely scenarios for service deployment and competition to develop over the UFB. The analytical framework reveals that the UFB ecosystem will be fraught with cross-network externalities which are the basis for regulatory decisions already adopted and the source of particular forms of strategic behavior adopted by the UFB-based market innovators.