Financial leverage and market volatility with diverse beliefs

We study a general equilibrium model of asset trading with financial leverage, where the investors can engage in speculative trading with diverse beliefs about the asset??s fundamental value. We show that an increase in the leverage ratio causes the stock price to rise in the current period through a ??leverage effect??, and will result in more borrowing and more stock purchase that pumps the stock price higher in the subsequent period, known as the ??pyramiding effect??. There can also be a ??depyramiding effect?? when the price falls because lenders issue margin calls and force stock sales, contributing to further stock price plummeting. Price changes from depyramiding effect, however, may not take effect when margin calls are not triggered. We demonstrate that, under certain conditions, decreasing leverage ratios leads to lower stock price volatility, measured by the variation of prices caused by an exogenous shock, when the shock is unanticipated. The influences of dispersion of beliefs and available investment funds on the relation between financial leverage and market volatility are also examined. When the shock is anticipated, we demonstrate that reducing leverage ratios may not lower stock price volatility, which poses an important challenge to future studies on this issue.     

Information Transmission Through Rumors in Stock Markets: A New Evidence

The authors provide new evidence of the influence of false rumors based on Taiwan's stock market. The results indicate significant patterns of abnormal returns and trading volumes surrounding the event day and that the rumors seem to be disseminated in the stock market before appearing in newspapers. The results also indicate asymmetry: Investors hearing a positive rumor about a stock may tend to buy the stock, prompting a price run-up until the rumor dies away, while negative rumors usually have greater and longer negative impacts on stock returns than positive rumors do. The presence of a daily price limit is negatively correlated to the size of abnormal returns and abnormal trading volumes on the event day, and the abnormal trading volumes are more sensitive to the price limit surrounding the event day. Finally, firm managers might receive rumor information earlier and then conduct stock trading before the rumor's announcement.     

Endogenous Firm Objectives

We analyze the behavior of a monopolistic firm in general equilibrium when the firm's decisions are taken through shareholder voting. We show that, depending on the underlying distribution, rational voting may imply overproduction as well as underproduction, relative to the efficient level. Any initial distribution of shares is an equilibrium, if individuals do not recognize their influence on voting when trading shares. However, when they do, and there are no short–selling constraints, the only equilibrium is the efficient one. With short–selling constraints typically underproduction occurs. It is not market power itself causing underproduction, but the inability to perfectly trade the rights to market power.     

KEIRETSU SHAREHOLDING TIES: ANTITRUST ISSUES

Antitrust concern about keiretsu shareholding ties is misplaced and at odds with economic reasoning and with empirical investigation. Holding stock in a trading partner slants the bargaining over product market variables in favor of the trading partner. Divesting such a stock interest accomplishes the reverse. The firm holding shares in a trading partner can credibly threaten to divest should the trading partner behave opportunistically. Divesting withdraws the bargaining advantage that the equity position had conferred. Therefore, a firm may establish a partial equity position in a trading partner to deter opportunism. Additionally, Japanese banks' shareholding in the companies to which they lend resolves agency problems and lowers borrowing costs. Organizing firms into cross-shareholding groups magnifies these favorable effects by assuring that direct shareholding by banks gives rise to indirect shareholding as well. Keiretsu shareholding ties impede U.S. exports to Japan because they lower the keiretsu members' costs of transacting with one another and not because they raise rivals' costs .     

On Pollution Permit Banking and Market Power

We consider a pollution permit market with a large firm and fringe of competitive firms. To smooth compliance towards a long-run emissions goal, firms are initially allocated a stock (i.e., bank) of permits that can be gradually consumed. We first show how the large firm can credibly manipulate the spot market in subgame-perfect equilibrium. Motivated by features observed in the US market for sulfur dioxide emissions, we then show that the introduction of stock transactions has no effects on market power, but that forward trading and incomplete observability of stock holdings do have pro-competitive effects. Both authors are also Research Associates at the MIT Center for Energy and Environmental Policy Research.     

Price Volatility and Risk Exposure: On the Interaction of Quota and Product Markets

We consider an industry with firms that produce a final good emitting pollution to different degree as a side effect. Pollution is regulated by a tradable quota system where some quotas may have been allocated at the outset, i.e. before the quota market is opened. We study how volatility in quota price affects firm behaviour, taking into account the impact of quota price on final-good price. The impact on the individual firm differs depending on how polluting it is??whether it is ??clean?? or ??dirty????and whether it has been allocated quotas at the outset. In the absence of long-term or forward contracting, a grandfathering regime??where clean firms are allocated no quotas and dirty firms are allocated quotas for a part of their emissions??minimizes the impact on firm behavior relative to a risk-neutral benchmark.With forward contracts and in the absence of wealth effects initial quota allocation has no effect on firm behaviour. Allowing for abatement does not change the qualitative nature of our results.     

Labour contracts in a stock market economy

In this paper, labour contracts are examined in the context of a general stock market economy where all shareholders are risk averse, and firms act in shareholders interest. The problem considered is whether some firm can offer a wage contract that will make all its shareholders better off. We show by example that, contrary to the arguments in the partial equilibrium framework, it is possible that no such contract will exist, even when there are potential gains to risk sharing. A sufficient condition for the existence of a feasible pareto improving contract is given. It is shown that contract trading will arise provided some firm has no large shareholders.     

Manipulation and the Allocational Role of Prices

It is commonly believed that prices in secondary financial markets play an important allocational role because they contain information that facilitates the efficient allocation of resources. This paper identifies a limitation inherent in this role of prices. It shows that the presence of a feedback effect from the financial market to the real value of a firm creates an incentive for an uninformed trader to sell the firm's stock. When this happens the informativeness of the stock price decreases, and the beneficial allocational role of the financial market weakens. The trader profits from this trading strategy, partly because his trading distorts the firm's investment. We therefore refer to this strategy as manipulation . We show that trading without information is profitable only with sell orders, driving a wedge between the allocational implications of buyer and seller initiated speculation, and providing justification for restrictions on short sales.     

融券制度与内部人寻租——来自准自然实验的经验证据

内部人寻租一直以来是理论与实务界关心的重点,如何有效抑制内部人寻租行为是资本市场的重大课题。本文以内部人交易度量内部人寻租,分析了融券制度对内部人寻租的影响。研究发现:(1)融券制度对内部人寻租有显著抑制作用,并且融券规模越大,内部人寻租越少。(2)相比于国有企业,非国有企业当中融券制度对内部人寻租的抑制作用更加明显。本文还将内部人交易分方向进行回归,结果显示融券制度对内部人寻租的抑制作用主要体现在卖出方向上。本文进一步分析了融券制度影响内部人寻租的路径,发现“竞争效应”和“信息效应”是融券制度影响内部人寻租的两条重要路径。本文考虑了竞争性解释——分析师关注的作用,发现分析师关注并不能影响本文结论的正确性;本文还利用反面事实推断、倾向得分匹配、反向因果检验等方法,确保实证结论的稳健性。本文的研究结果,丰富了内部人寻租的特征及影响因素研究,有利于市场监管部门加强对内部人寻租行为的控制;扩充了有关融券制度的文献,为卖空制度的推行及完善提供理论依据。     

Real and financial effects of insider trading with correlated signals

Summary. In this paper we study the real and financial effects of insider trading in a Static, Kyle-type model. In our model the insider is also the manager of the firm. Hence the insider chooses both the amount of the real output to be produced and the amount of the stock of the firm to trade. The aim of the paper is to study the relationship between financial decisions and real decisions. In particular, we examine how insider trading on the stock market affects the real output and price and how the real decision making affects the financial variables, such as the extent of insider trading, stock prices, and the stock pricing rule of the market maker. In the model, the market maker observes two correlated signals: the total order flow and the market price of the real good. We study the informativeness of the stock price and the effects on insider's profits. We also construct a compensation scheme that aligns the interests of the insider and the firm. Finally, we generalize the pricing rule set up by a competitive market maker and analyze the comparative statics of the model. Received: October 3, 1999: revised version: December 1, 1999     

市场分割下中国股市反馈交易实证研究——来自A股、B股和H股市场的经验证据

文章在行为资本资产定价模型(BCAPM)的基础上,通过借鉴Watanabe(2002)的方法,建立了GJR-GARCHM(1,1)-M模型,充分考虑中国股票市场处于分割状态的现状,使用基本覆盖A股、B股和H股市场全部交易历史的市场指数日收盘价数据,对A股、B股和H股市场的反馈交易行为进行研究和比较,结果显示:A股和B股市场都存在显著的正反馈交易效应,反馈交易行为主要取决于波动率水平和市场涨跌两个因素;与成熟股票市场类似,H股和红筹股市场的正反馈交易行为不显著;A股市场的反馈交易行为受市场涨跌因素影响更大,而B股市场的反馈交易行为主要由波动率水平决定;深市比沪市更容易出现正反馈交易者主导市场的现象。文章的研究不仅对行为资本资产定价理论的成立提供了经验性证据,而且对投资经理的实践操作和政策制定者的监管调控都具有一定的参考价值。     

我国证券市场正反馈交易的实证检验

正反馈交易是投资者依据证券t-1期收益高低决定其第t期买卖行为的一种交易策略,这种交易策略广泛存在于世界各国的证券市场中,使证券市场表现出超常的波动性。本文使用上证指数和深证指数对我国证券市场的正反馈交易进行了实证研究,结果显示我国证券市场同样存在显著的正反馈交易现象,这种现象降低了市场的稳定性。     

#br# 融资融券加大了沪深股市波动吗*

融资融券设计初衷是通过融资加强市场流动性和通过融券提供投资者规避价格下跌风险的金融工具，改善由供求关系严重失衡导致市场巨幅震荡的局面，实现资本市场长期稳定的目标。实际操作中，融资融券疏通货币市场和资本市场间的资金流动，撬动巨额资金涌入股市；融资规模扩张过快而融券做空力量薄弱，业务结构发展严重失衡，导致两融业务具有“小冲击、大波动”的金融加速效应，放大了外部冲击引起股价上涨和下跌的幅度。协整回归分析表明，两融业务规模的扩张和收缩对上证指数涨跌具有显著的同向影响。TGARCH事件模型结果进一步证实融资融券从稳定股价到加剧波动的功能变化。随着标的股票扩容和业务常规化，两融业务导致股市投机过度，加剧了沪深两市的资产价格异动，没有达到平抑波动的设计预期。     

投资者保护具有股票流动性效应——来自中国高频交易数据的经验证据

股权分置改革使得股票市场的资源配置功能得到了进一步的发挥,但大股东使用内幕交易等手段侵害中小股东利益的行为也会变得更加突出。在以往的研究中,人们仅关注了投资者保护对关联交易等"利益输送"行为的遏制作用,并没有关注投资者保护对内幕交易等"利益输送"行为的治理效应。事实上,加强投资者保护能够改善信息环境,减少内幕交易行为,这将导致股票流动性的上升和信息不对称程度的下降。这一结论对于股权分置改革后的中国证券市场具有尤为重要的指导意义。     

融资融券交易的市场冲击效应研究——基于中国台湾证券市场的经验与启示

融资融券交易是证券市场的重要组成部分,它的推出会对整个市场产生何种影响是非常值得研究的问题.文章利用中国台湾证券市场的融资融券交易数据,从市场流动性与波动性角度研究融资融券交易对整个市场的冲击效应.研究结果表明,融资买空交易有助于提升整个市场的流动性水平,在一定程度上可以改善市场流动性水平相对不足的状况,但融券卖空交易对市场流动性水平没有显著影响;融资买空与融券卖空交易并未显著影响整个市场的波动性水平.文章建议证券监管部门可以将融资融券交易保证金率作为市场调控工具,通过适时调整保证金率调控整个市场,避免市场出现大幅震荡.     

Exchange rate fluctuations in an economy with noise traders

This paper analyzes the stability of the exchange rate in an economy with noise traders. Noise trading is restricted to agents investing in the domestic stock market. The agents pricing foreign exchange hold rational expectations. Monetary policy is affected by the behavior of investors in the domestic stock market and in turn affects fundamental stock evaluations as well as noise trading. We show that when monetary policy affects only fundamentalists bifurcation appears in the exchange rate. When monetary policy also affects noise trading, fixing the exchange rate or switching to a low money growth rule imply stock bubbles converge to zero.     

个人投资者交易行为研究——来自台湾股市的证据

本文基于台湾股市数据,主要研究个人投资者的交易行为。参照Kaniel et al.(2008)构建了个人投资者交易不平衡性指标─净交易,以反映投资者股票交易的强度。采用这种交易不平衡性指标来构建投资组合研究个人投资者的交易行为。首先研究个人投资者交易和股票的收益之间的动态关系从而分析投资者的交易策略,然后研究个人投资者净交易的收益预测能力从而分析个人投资者交易的信息含量。本文研究发现:台湾股票市场的个人投资者采用负反馈的交易策略,并且个人投资者在交易中表现出很强的处置效应;个人投资者在交易中的信息含量不足;个人投资者交易中的盈利主要来自两个方面:过度反应和价格冲击。文章最后给出政策建议。     

动量和反转投资策略在我国股市中的实证分析

本文采用沪深两市1995年前上市的股票作为样本,发现我国股市中也存在明显的动量和反转盈利,且两种效应的强弱与大盘走势相关,当市场为牛市特征时,动量效应明显强于反转效应;当市场为熊市特征时,则反之.经典的CAPM模型无法解释动量和反转盈利的来源,检验表明投资者对不同类型信息的不同反应方式,可以很好解释我国股市中的动量和反转盈利,利用上述检验结果还可以解释我国股市中许多有趣的特征.     

Insider trading legislation and corporate governance

This paper analyzes the impact of insider trading legislation on corporate governance. In a context where large, dominant shareholders can monitor underperforming companies, managers have an incentive to give early warnings about adverse developments to dominant shareholders. This information is effectively a bribe to induce dominant shareholders to sell their stock and refrain from intervention. If insider trading is unregulated, dominant shareholders collude with management at the expense of small shareholders. The optimal regime forces the company to disclose all material information to the market. Private contracting between companies and shareholders leads to optimal insider trading regulation only if initial shareholders can enter a binding commitment, otherwise large shareholders and managers recontract at the expense of small shareholders. Enforcement also matters. European Union legislation requires inside information to be precise. Such a narrow definition creates a grey zone, where information is private but cannot be classified as inside information. As a result the effectiveness of corporate governance and firm value are reduced. Regulation in the US that treats shareholders with a stake exceeding 10% as insiders is potentially harmful.     

Dumping,antidumping duties,and price undertakings

This paper examines which types of firms, from a developed country (DC) or a less developed country (LDC), tend to practice dumping, using a two-market equilibrium analysis of trade in similar products. Specifically, we present a vertical product differentiation model of duopolistic competition between a DC firm and an LDC firm under free trade to show that the DC firm sells a higher-quality product without dumping. In contrast, the LDC firm sells a lower-quality product and practices dumping in the DC market by charging a price lower than the product's price in the LDC's local market. In response to the LDC dumping, the DC government's use of an optimal antidumping duty increases its domestic welfare. The LDC's social welfare may increase if its exporting firm accepts price undertaking rather than dumping. From the perspective of world welfare, defined by aggregating the welfare of the trading countries (DC and LDC), the trade damage measure through imposing antidumping fines on LDC dumping is Pareto-improving compared to free trade (under which dumping takes place) and price undertakings.