An Empirical Equilibrium Model of a Decentralized Asset Market

I estimate a search‐and‐bargaining model of a decentralized market to quantify the effects of trading frictions on asset allocations, asset prices, and welfare, and to quantify the effects of intermediaries that facilitate trade. Using business‐aircraft data, I find that, relative to the Walrasian benchmark, 18.3 percent of the assets are misallocated; prices are 19.2 percent lower; and the aggregate welfare losses equal 23.9 percent. Dealers play an important role in reducing trading frictions: In a market with no dealers, a larger fraction of assets would be misallocated, and prices would be higher. However, dealers reduce aggregate welfare because their operations are costly, and they impose a negative externality by decreasing the number of agents' direct transactions.     

Endogenous Liquidity and Defaultable Bonds

This paper studies the interaction between default and liquidity for corporate bonds that are traded in an over‐the‐counter secondary market with search frictions. Bargaining with dealers determines a bond's endogenous liquidity, which depends on both the firm fundamental and the time‐to‐maturity of the bond. Corporate default decisions interact with the endogenous secondary market liquidity via the rollover channel. A default‐liquidity loop arises: Assuming a relative illiquid secondary bond market in default, earlier endogenous default worsens a bond's secondary market liquidity, which amplifies equity holders' rollover losses, which in turn leads to earlier endogenous default. Besides characterizing in closed form the full interdependence between liquidity and default for credit spreads, our calibrated model can jointly match empirically observed credit spreads and liquidity measures of bonds across different rating classes.     

Competing Mechanisms in a Common Value Environment

Consider strategic risk‐neutral traders competing in schedules to supply liquidity to a risk‐averse agent who is privately informed about the value of the asset and his hedging needs. Imperfect competition in this common value environment is analyzed as a multi‐principal game in which liquidity suppliers offer trading mechanisms in a decentralized way. Each liquidity supplier behaves as a monopolist facing a residual demand curve resulting from the maximizing behavior of the informed agent and the trading mechanisms offered by his competitors. There exists a unique equilibrium in convex schedules. It is symmetric and differentiable and exhibits typical features of market‐power: Equilibrium trading volume is lower than ex ante efficiency would require. Liquidity suppliers charge positive mark‐ups and make positive expected profits, but these profits decrease with the number of competitors. In the limit, as this number goes to infinity, ask (resp. bid) prices converge towards the upper (resp. lower) tail expectations obtained in Glosten (1994) and expected profits are zero.     

奈特不确定性下的资产及其组合的惰性区间

不确定性是证券市场的基本特征之一,是资产定价和投资者交易行为等研究的主要内容。标准期望效用理论认为投资者具有唯一的资产执行价格,当市场价格高于执行价格时,投资者出售资产;反之,则会购进。然而,源于不确定性的存在,资产的均衡价格或交易价格并非某一确定值而是某一区间;在此区间内,投资者无交易行为,我们称之为资产的惰性区间。本文假定投资者是不确定性规避型,基于可行域上的容度,引入测度奈特不确定性程度的等级参数,研究奈特不确定性下的资产及其组合的惰性区间。基于容度期望效用模型,利用容度代替概率测度表征投资者预期效用,提出奈特不确定性下投资者决策行为的偏好表达式;基于对偶测度构建资产交易的惰性区间,分析奈特不确定性程度与惰性区间的关系;最后,基于Black-Scholes期权定价模型,选择存续期为2008年10月-2011年8月的江铜认购权证和长虹认购权证为研究对象,以其单资产及不同比例资产组合的日收益数据为样本予以实证。结果表明：随着奈特不确定性程度的不断增强（减弱）,资产及其组合的惰性区间不断扩大（缩小）,市场流动性随之下降（上升）;随着奈特不确定性程度的增强,高价格、高波动率的资产及其组合的惰性区间变化更为明显;在适度的奈特不确定性程度范围内,高波动率的资产及其组合的交易相对活跃。研究解释了证券市场上的“非市场参与”之谜和“特质波动率”之谜,说明了证券市场上的“有限市场参与”特征,为资产定价与市场流动性关系的研究提供了参考。     

Strategic Liquidity Provision in Limit Order Markets

We characterize and prove the existence of Nash equilibrium in a limit order market with a finite number of risk‐neutral liquidity providers. We show that if there is sufficient adverse selection, then pointwise optimization (maximizing in p for each q) in a certain nonlinear pricing game produces a Nash equilibrium in the limit order market. The need for a sufficient degree of adverse selection does not vanish as the number of liquidity providers increases. Our formulation of the nonlinear pricing game encompasses various specifications of informed and liquidity trading, including the case in which nature chooses whether the market‐order trader is informed or a liquidity trader. We solve for an equilibrium analytically in various examples and also present examples in which the first‐order condition for pointwise optimization does not define an equilibrium, because the amount of adverse selection is insufficient.     

ON‐THE‐JOB SEARCH AND MORAL HAZARD

We analyze the interaction between intertemporal incentive contracts and search frictions associated with on‐the‐job search. In our model, agency problems call for wage contracts with deferred compensation. At the same time workers do on‐the‐job search. Deferred compensation improves workers' incentives to exert effort but distorts their on‐the‐job search decisions. We show that deferred compensation is less attractive when the value to the worker–firm pair of on‐the‐job search is high. Moreover, the interplay between search frictions and wage contracts creates feedback effects. If firms in equilibrium use contracts with deferred compensation, fewer firms with vacancies enter the on‐the‐job search market, and this in turn reduces the distortions created by deferred compensation. These feedback effects between the incentive contracts used and the activity level in the search markets can lead to multiple equilibria: a low‐turnover equilibrium where firms use deferred compensation, and a high‐turnover equilibrium where they do not. Furthermore, the model predicts that firms are more likely to use deferred compensation when search frictions are high and when the gains from on‐the‐job search are small.     

多基本面下异质交易者竞争及流动性分析

假设风险资产出清价值由多个基本面组成，比较分析了同质与异质信息结构下交易者策略的相互作用及对市场的影响。结果发现：交易者人数增加所导致的竞争会提高市场流动性及市场信息效率，同时对同质交易者产生挤出效应和对异质交易者产生促进效应；异质知情交易者在私人信息质量方面的竞争则会加剧市场信息不对称程度，降低市场流动性；异质交易者间通过信息质量的竞争决定收益分配。理论上，市场流动性存在最佳状态。     

流动性风险、投资者流动性需求与资产定价

依据证券市场的交易特点把投资者面临的市场流动性风险分解为外生和内生流动性风险,并引入流动性需求状态变量随机化了的投资者对证券的持有期限,得出基于流动性风险调整的资产定价模型.模型能够解释实证研究发现的投资者对流动性风险中不可分散的系统性部分要求相应的风险补偿现象.而且模型揭示出,流动性水平和市场流动性风险的补偿要求是投资者的流动性需求紧张程度的增函数,解释了流动性风险溢价的时变性现象.     

流动性供给与日内价格效率——基于中国股票市场的实证研究

本文基于中国A股市场高频交易数据从流动性供给的角度探究提高价格效率的途径，并结合信息交易和市场状态分析流动性供给与日内价格效率的关系。用短期收益的可预测程度来衡量价格效率，用逆势交易比例来衡量流动性供给水平，基于日内分时数据建立面板回归模型对流动性供给与价格效率之间的关系进行实证分析。结果表明，提高流动性供给能够促进日内价格效率的改善，同时较高的机构交易比例和较低的价格波动对流动性供给与价格效率之间的关系有正向促进作用。研究结论对于提高价格效率，稳定和完善市场具有启示作用。     

Sorting and Decentralized Price Competition

We investigate the role of search frictions in markets with price competition and how it leads to sorting of heterogeneous agents. There are two aspects of value creation: the match value when two agents actually trade and the probability of trading governed by the search technology. We show that positive assortative matching obtains when complementarities in the former outweigh complementarities in the latter. This happens if and only if the match‐value function is root‐supermodular, that is, its nth root is supermodular, where n reflects the elasticity of substitution of the search technology. This condition is weaker than the condition required for positive assortative matching in markets with random search.     

期现货市场订单流动性层面的“遛狗效应”——基于交易量刻度的高频交易数据研究

在多层次资本市场的大发展趋势下,建立有效的衍生品-现货互补对冲机制是完善金融市场的基本要求。期货-现货体系为投资者提供套期保值风险对冲功能对期货与现货合约的紧密联系程度提出非常高的要求,这不仅应体现在价格上,更应微观的体现在交易过程的订单流动性中。若在任何情形下,订单流动性的趋同能够立刻反应在两类金融证券中,那么异常的基差风险就很难发生,股指期货与现货之间将存在健康的"遛狗效应"。本文以期货现货合约的高频交易数据为基础,构建期货和现货合约的订单流动性,并通过期现货订单流动性传染互动模型的合理性检验期现货合约之间是否在微观订单流动性层面在平常交易日存在紧密的"遛狗效应"。在高频数据模型构建中,使用成交量刻度的衡量方法,并说明了其较时间刻度的优势。在实证研究中,本文使用股指期货和沪深300指数现货的高频交易数据,证明了我国股指期货和现货之间在平常交易日中存在紧密的"遛狗效应"。     

基于流动性风险的资本资产定价模型

在现有的资产定价理论基础上,研究了考虑流动性风险因素的风险资产定价问题。首先在无套利下对流动性风险进行定价,得到流动性风险的市场价格,进而给出了无风险资产和风险资产的有效前沿。再从风险构成的角度给出了流动性风险的测度和市场价格,推导出两种形式的基于流动性风险的资本资产定价模型(以相对量表示风险的LBCAPM和以绝对量表示风险的LBCAPM)并揭示了资产期望回报的形成过程。最后,介绍了定价模型的应用前景。     

卖空制度、流动性与信息不对称问题研究———香港市场的个案

应用香港市场的案例, 研究了引入卖空制度后个股的交易活跃程度、流动性、波动性与信息不对称的变化, 提出了噪声交易者假说, 即引入卖空制度后重要的变化是噪声交易者会出于对更高亏损可能的担心而退出交易或变得谨慎.实证结果发现:引入卖空制度会带来交易活跃程度下降、流动性下降以及信息不对称水平升高.同时, 通过对知情交易概率(PIN)的分析发现, 在引入卖空制度后, PIN值确实呈现出显著升高的趋势, 而使其升高的因素就是噪声交易者参与程度降低.噪声交易者假说较好地解释了上述现象.     

中国股市总流动性与资产定价关系实证研究

我们建立了一个包含市场风险和两种流动性风险的三因素资产定价模型,研究中国股市总的市场流动性风险是否在资产定价中得到了反映,其中流动性风险包括用协方差度量的市场收益对总流动性的敏感性风险和用方差度量的总流动性的波动性风险。研究结果表明,中国股市不仅存在显著的市场风险溢价,而且存在显著的流动性风险溢价,而流动性风险中市场收益对总流动性的敏感性风险对资产定价的影响更为显著。     

FINANCIAL FRAGILITY,LIQUIDITY, AND ASSET PRICES

We define a financial system to be fragile if small shocks have disproportionately large effects. In a model of financial intermediation, we show that small shocks to the demand for liquidity cause either high asset‐price volatility or bank defaults or both. Furthermore, as the liquidity shocks become vanishingly small, the asset‐price volatility is bounded away from zero. In the limit economy, with no shocks, there are many equilibria. However, if banks face idiosyncratic liquidity shocks, then the only equilibria that are robust to the introduction of small aggregate risk involve stochastic consumption as well as volatile asset, prices. (JEL: D5, D8, G2)     

PUBLIC DEBT UNDER LIMITED PRIVATE CREDIT

There is a conventional wisdom in economics that public debt can serve as a substitute for private credit if private borrowing is limited. The purpose of this paper is to show that, while a government could in principle use such a policy to fully relax borrowing limits, this is not generally optimal. In our economy, agents invest in a short‐term asset, a long‐term asset, and government bonds. Agents are subject to idiosyncratic liquidity shocks prior to the maturity of the long‐term asset. We show that a high public debt policy fully relaxes private borrowing limits and is suboptimal. This is because agents expecting such a policy respond by investing less than is socially optimal in the short asset which can protect them in the event of a liquidity shock. The optimal policy is more constrained and it induces a wedge between the technological rate of return on the long asset and the rate of return on bonds. In such a regime, agents subject to liquidity shocks are also borrowing constrained, and this expectation of being borrowing constrained induces them to invest the optimal level in the short asset.     

融资流动性与市场流动性

市场流动性刻画市场的交易能力,融资流动性反映投资者的融资能力,两种流动性及其相关程度是衡量金融市场健康发展的重要指标,为了控制与防范危机时期金融市场的风险,有必要准确分析和量化融资流动性与市场流动性的关系。以融资流动性和股票市场流动性为研究对象,以美国次级债危机作为研究背景,选择2000年1月3日～2008年4月30日作为样本区间,运用DCC-MVGARCH模型估计融资流动性与股票市场流动性之间的动态相关系数,并通过t检验对比金融危机前后两者之间动态条件相关系数的时间走势,以证实两种流动性在危机时期是否存在相互增强的促进作用。实证结果表明,危机爆发前,融资流动性与股票市场流动性的动态相关性较低,且相对稳定,但危机爆发后,两种流动性的相关性显著增强,且波动程度变大,呈现出流动性螺旋的现象。这一结论为危机中市场流动性突然消失提供了理论解释,并以此提出提升市场流动性的相关政策和建议。     

Inefficient Investment Waves

We show that firms' individually optimal liquidity management results in socially inefficient boom‐and‐bust patterns. Financially constrained firms decide on the level of their liquid resources facing cash‐flow shocks and time‐varying investment opportunities. Firms' liquidity management decisions generate simultaneous waves in aggregate cash holdings and investment, even if technology remains constant. These investment waves are not constrained efficient in general, because the social and private value of liquidity differs. The resulting pecuniary externality affects incentives differentially depending on the state of the economy, and often overinvestment occurs during booms and underinvestment occurs during recessions. In general, policies intended to mitigate underinvestment raise prices during recessions, making overinvestment during booms worse. However, a well‐designed price‐support policy will increase welfare in both booms and recessions.     

锚定比率可以衡量股价高估吗？——基于崩盘风险视角的经验证据

股价高估指的是公司市场价值超出其内在价值的现象,但如何衡量内在价值一直存在争议。借鉴行为金融文献中锚定效应的概念,结合中国资本市场的特殊性,本文提出了锚定比率(简称"RPR")这一新的股价高估指标。为了证实该指标的有效性,本文利用事后的股价崩盘风险进行了相关检验。结果表明:第一,锚定比率与股价崩盘风险正相关;第二,更少的分析师跟踪、更多的散户持股以及更高的股票流动性均会强化锚定比率对股价崩盘风险的影响;第三,在控制常用的股价高估指标、两类代理问题和管理层"捂盘"行为后,本文的结果依然成立;第四,利用崩盘事件,本文证实了锚定比率会加剧股价下跌的程度,且长期来看股价会保持"惯性"而非"反转"。本文的研究表明投资者做决策时对股价高点存在明显的锚定效应,丰富了锚定效应在中国资本市场中的运用。更重要的是,本文提出了一个可能更适合于中国资本市场的股价高估指标,该指标意味着资本市场定价机制的不完善是导致股价高估和频繁崩盘的重要原因,这对于改善资本市场定价效率、降低股价崩盘风险有一定的启示作用。     

卖空制度、流动性与信息不对称问题研究——香港市场的个案

应用香港市场的案例,研究了引入卖空制度后个股的交易活跃程度、流动性、波动性与信息不对称的变化,提出了噪声交易者假说,即引入卖空制度后重要的变化是噪声交易者会出于对更高亏损可能的担心而退出交易或变得谨慎.实证结果发现:引入卖空制度会带来交易活跃程度下降、流动性下降以及信息不对称水平升高.同时,通过对知情交易概率(PIN)...