The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

试论市场经济条件下的经济计划

在商品货币关系广泛存在的情况下,要想恰当有效地按比例分配社会劳动时间,既离不开市场的作用,也离不开计划的作用。这既为资本主义社会的实践所证明,也为社会主义社会的实践所证明。对这个问题进行深层次的分析,可以从生产关系与生产力、上层建筑与经济基础的关系上,从计划与市场的内在统一性上。从计划与市场两种手段的不同特点上找到理论根据。在市场经济条件下,并不排斥计划的作用,但计划工作必须进行改革使之与发展市场经济相适应。     

The division of labour and market structure

Most firms produce most of the time under conditions of substantial economies of scale. The division of labour, according to Adam Smith the mainspring of wealth, is intrinsically an economies of scale phenomenon. Market structure in most industries in characterized by a small number of suppliers and a larger number of customers. I explain this law of small numbers as the equilibrium of two forces: the deconcentration effect of imitation and the market spliting effect of further refinements in the division of labour by innovation. A deconcentrated market creates larger incentives for market splitting (product differentiation) by innovation than a concentrated market. But market splitting raises concentration in the market and it raises the number of different markets in the economy. Before the economies of scale of old products are fully exploited, new products are being offered which again are produced under conditions of economies of scale.     

我国资本市场存在的制度功能缺陷与对策

我国资本市场是在新旧体制转换中建立起来的，先天就存在着制度和市场功能方面的缺陷，亟需要采取有效应对策略以弥补，使我国资本市场的发展走上正常轨道。     

采取网络型的政府市场供给模式应对房价问题

面对不断飙升的房价,从理论界到政策层面对其原因都有不同的解读,但从实践结果来看对房价的治理并不理想。本文在综合分析理论研究与国家调控政策的基础上,认为创新措施采取网络型的政府市场供给模式是解决房价过快上涨的有效途径。文章着重对这一模式进行了分析,并认为此举对缓解供需矛盾、解决市场的信息不对称、市场操控、改变预期、稳定房价等都有非常重要的作用。     

“万村千乡”推广悖论及其解决方案

在农村消费市场存在差异的条件下，全国范围的以行政补贴和市场推广相结合的“万村千乡”推广方式将面临“推广悖论”，即工程的普遍服务职能与企业追求利润的目标之间的冲突，进而可能会造成财政补贴资金的浪费。应在不同区域采用不同的推广策略：发达地区农村，应以企业自主经营为主；具有一定消费市场潜力但企业开拓成本还比较高的地区，应行政补贴和市场推广相结合；尚不具备经营条件的农村地区，应加强基础设施建设，并提高农民收入水平，待时机成熟后再逐步推进。     

Information–driven trading at the Prague Stock Exchange: Evidence from Intra–Day Data

Many observers argue that informed and insider trading is widespread in the emerging financial markets of transition countries, yet rigorous treatment of this issue has been virtually non–existent. The current paper estimates the extent of informed trading on the Prague Stock Exchange (PSE) using intra–day transaction data. Our estimates confirm that the average share of informed trading is equal to 0.32, which is high relative to developed markets and varies considerably among stocks. Using the Easley et al. (1996) approach on the very best segment of the PSE we obtained a high average probability of informed trading. Since data used in this study cover the period after the major attempts to improve market regulations, our results indicate that the PSE needs further strengthening to recover credibility and to become a real source of corporate financing. JEL classification: G14, G15.     

我国企业融资制度的现状及问题

细致分析了我国企业融资制度的现状,在此基础上指出我国企业融资制度存在的问题与缺陷,并提出了一些改善现有企业融资制度缺陷的建议和办法。     

Does a Switch of Budget Regimes Affect Investment and Managerial Discretion of State-Owned Enterprises? Evidence from Italian Firms

We investigate the investment decisions of Italian state-owned enterprises (SOEs) across budget constraint regimes and carry out a natural experiment that exploits a regime switch in 1987. Drawing on the theory of capital market imperfections, we apply an empirical framework for investment analysis to a panel of manufacturing SOEs in competitive industries. We identify parallels between SOEs and widely held, quoted companies afflicted by agency problems, managerial discretion, and overinvestment. We argue that, in the case of SOEs, the soft budget regime increases managerial discretion, facilitates collusion with vote-seeking politicians, and results in wasteful investment. Consistent with our predictions, we find that the regime switch disciplines SOE's investment behavior. Following a hardening of the budget constraint, managers lose discretion to indulge in collusion and overinvestment. J. Comp. Econ., June 2002 30(4), pp. 787–811. London School of Economics and Political Science, Houghton Street, London WC2A 2AE, United Kingdom; and CERIS–CNR, Institute for Economic Research on Firms and Growth, National Research Council, Via Avogadro, 8, 10121 Turin, Italy. © 2002 Association for Comparative Economic Studies. Published by Elsevier Science (USA). All rights reserved.Journal of Economic Literature Classification Numbers: E32, G31, G32, L32, M40.