基于行为主从博弈模型的股票价格分析

资产定价问题随着金融产业的快速发展成为金融学家们争相研究的对象,影响风险资产价格变化的因素也随着研究的不断深入而不断显露出来。在Kyle模型的基础上,在股票市场中引入贴近实际的趋势交易商,构建了以知情交易商为主导,趋势交易商采取适应性策略的主从博弈模型,给出了市场均衡时的股票价格。同时,运用数值方法分析了知情交易商和趋势交易商博弈行为对股票均衡价格的影响,结果显示趋势交易商的决策会影响市场的均衡价格,两类交易者博弈的结果甚至会造成不同方向的变化趋势。最后,通过案例验证了模型结论的有效性,并为市场分析和投资者实际决策提供理论的支撑。     

信息不对称、过度自信与股价变动

信息传导的非同步和投资者情绪变化是股票市场的两个典型特征,前者会引发投资者之间出现信息不对称问题,后者主要体现为投资者过度自信,两者共同作用影响股票价格变动。本文将信息不对称和投资者过度自信情绪置于同一个分析框架,建立两阶段动态序贯定价理论模型研究现实市场上信息传导过程中股价变动的内在机制。结果表明:(1)面临新信息的进入,投资者对股票收益预期的调整与均衡价格之间具有正相关关系;(2)面临有利消息时,过度自信投资者比例越大,股票的均衡价格越高,投资收益将越低;面临不利消息时则相反;(3)随着过度自信投资者比例以及过度自信程度升高,市场风险溢价将下降;(4)投资者群体在信息传导过程中出现分化,对股价变动形成异质信念,未获取信息和获取信息但未出现过度自信的投资者认为股价被高估,获取信息且出现过度自信的投资者认为价格被低估,促使更多的交易,引发市场成交量和股价变动;(5)过度自信投资者比例与过度自信程度提高均会对市场效率产生正向影响,而对市场深度具有负向效应。最后,基于理论结果对非对称性和持续性等典型的市场波动性特征进行解释。     

锚定信念、投资者行为与风险资产定价

锚定效应影响投资者信念的更新进而影响风险资产定价。本文以Ornstein-Uhlenbeck过程刻画投资者锚定信念的均值回归过程,构建基于异质锚定信念的资产定价模型,推导出持有不同锚定信念的投资者对风险资产的需求及资产均衡价格。通过数值模拟研究表明：投资者锚定信念对风险资产均衡价格的形成产生不对称作用;异质锚定信念影响投资者对风险资产持有行为,进而对市场流动性、波动性和市场效率产生影响。     

资本资产定价模型的扩展及其参数确定

在马柯维茨开创性工作———均值-方差分析的基础上,威廉·夏普(William Sharpe)、约翰·林特纳(John Lintner)和简·莫辛(Jan Mossin)研究了在竞争均衡市场中金融资产的价格形成,并于1965年前后分别独立提出了资本资产定价模型(CAPM)。资本资产定价模型(CAPM)是在完善的资本市场中建立的,它有许多前提性的假设条件,建立模型的基本假设有:1)投资者是价格的接受者;2)投资者是理性的;3)市场环境是无摩擦的;4)投资者都只计划持有资产一个相同的周期;5)投资者只能交易公开交易的金融工具;6)一致预期假设(也就是说,所有的投资者都以相同的…     

金融研究动态

流动性对资产价格的影响前不久,美国麻省理工学院金融系教授、清华大学中国金融研究中心主任王江在清华大学经济管理学院做了题为“流动性的涵义及对资产价格的影响”的学术报告。王江教授向与会者展示了一个均衡模型,以解释流动性的涵义以及它对资产价格的影响。他说,如果投资者参与交易是需要成本的,则投资者     

欧洲信贷资产流转市场调查研究

2017年7月,银行业信贷资产登记流转中心(以下简称"银登中心")考察小组赴英、法两国同业机构交流,期间先后访问了多家行业协会和金融机构,就欧洲信贷资产流转市场的基础设施、平台公司、自律组织等进行了考察调研。调研发现,欧洲信贷资产流转市场在三十多年的发展历程中,交易品种和交易模式逐渐丰富,具有行业自律作用突出、投资者结构多元化、市场分散度高且区域性强等特点,这对于金融基础设施服务的要求不断提高。在此基础上,本文从促进我国信贷资产流转市场进一步发展的角度出发,提出了制定并推广行业标准、完善金融基础设施服务、继续研究贷款评级和价格发现机制、推动银团贷款流转业务等建议。     

现券市场做市报价点差的微观特征分析

交易机制与价格发现的关系一直是金融市场微观结构的重要研究方向,其目的是为了发现金融市场如何借由微观行为的不均衡实现市场层面的价格均衡过程。事实上,交易机制、交易习惯和市场均衡过程三者之间是相互影响的关系。分析和研究这三者的内在联系可以加深我们对市场的理解,并找到提高市场资源配置效率的途径。文章以做市报价收益率点差作为研究对象,详细分析了其时间分布、相关性、波动性及时间持续性等微观特征,为深入研究做市商报价和交易行为提供各种可能的切入点。     

投资者异质、卖空限制与市场均衡

根据投资策略的不同,投资者可以分为基本面投资者与技术投资者.在卖空限制且没有新信息的影响下,价格最终会趋向于基本面投资者的估值,而技术投资者将离开市场.通过有无内幕交易的比较,发现在内幕交易下技术投资者具有策略优势,内幕交易金额越大,优势越明显,被吞没的价值也就越大.故监管当局不应关注投资者理性教育,而应关注内幕交易的监管.若内幕交易金额得到控制,投资者便会自然趋向理性而关注资产的基本价值.     

资产证券化、非同质投资者和金融稳定性--一个理论模型北大核心CSSCISSCI

在金融市场上,不同的投资者对资产的利用效率不同,面对经济冲击时的稳健性不同。同时,由于金融市场的相互联系使得破产风险在不同投资者之间得以传染和扩散。本文构建了一个三期模型,刻画了银行证券化资产出售与非同质投资者和金融稳定性的关系。经济中的不确定性来自中间时段的经济冲击和资产价格波动。资产价格取决于经济中流动性的高低,由市场均衡决定。本文的研究显示,资产证券化在一定的程度上降低了系统性危机发生的概率。在投资者非同质的情况下,面临较大的负面经济冲击时次级投资者将首先陷入金融混乱,进而带来整个金融体系的不稳定。因此,政策制定者应根据不同投资者的资产利用能力,设置不同的投资门槛,以有效促进金融稳定。     

一般均衡下的金融市场流动性黑洞研究

本文在一般均衡框架下建立了考虑投资者多样化程度,投机交易者比例以及宏观货币政策稳定性三因素的两期交易模型,得到了金融市场受到流动性冲击后可能出现的三种均衡状态。当流动性冲击加大时,市场在一定条件下无法找到合理的出清价格而出现大幅下跌从而引发流动性黑洞事件。研究表明:投资者越是多样化、投机交易者比例越小、宏观货币政策带来的流动性冲击越小,市场出现极端流动性黑洞的可能性就越小。     

Information provision in financial markets

We set up a rational expectations model in which investors trade a risky asset based on a private signal they receive about the quality of the asset, and a public signal that represents a noisy aggregation of the private signals of all investors. Our model allows us to examine what happens to market performance (market depth, price efficiency, volume of trade, and expected welfare) when regulators can induce improved information provision in one of two ways. Regulations can be designed that either provide investors with more accurate information by improving the quality of prior information, or that enhance the transparency of the market by improving the quality of the public signal. In our rational expectations equilibrium, improving the quality of the public signal can be interpreted as a way of providing information about the anticipations and trading motives of all market participants. We find that both alternatives improve market depth. However, in the limit, we show that improving the precision of prior information is a more efficient way to do so. More accurate prior information decreases asymmetric information problems and consequently reduces the informativeness of prices, while a more accurate public signal increases price informativeness. The volume of trade is independent of the quality of prior information and is increasing in the quality of the public signal. Finally, expected welfare can sometimes fall as prior information or the public signal become more precise.     

A Rational Expectations Equilibrium with Informative Trading Volume

A large number of empirical studies find that trading volume contains information about the distribution of future returns. While these studies indicate that observing volume is helpful to an outside observer of the economy it is not clear how investors within the economy can learn from trading volume. In this paper, I show how trading volume helps investors to evaluate the precision of the aggregate information in the price. I construct a model that offers a closed‐form solution of a rational expectations equilibrium where all investors learn from (1) private signals, (2) the market price, and (3) aggregate trading volume.     

INTRADAY STEALTH TRADING: WHICH TRADES MOVE PRICES DURING PERIODS OF HIGH VOLUME?

Research documents a U-shaped intraday pattern of returns. We examine which trade sizes drive the U-shaped pattern and find that intraday price changes from larger trades exhibit a U-shaped pattern whereas price changes from smaller trades show a reverse U-shaped pattern. We argue that price changes from smaller trades are higher during the middle of the day because informed investors break up their trades to disguise their information when intraday volume is low. Price changes from larger trades are likely higher at the beginning and end of the day because high volume allows informed investors to increase their trade size without revealing their information to the market.     

Speculative dynamics and price behavior in the Shanghai Stock Exchange

This article examines the extent to which the trading behavior of heterogeneous investors manifests in stock price changes of asset portfolios which constitute the Shanghai Stock Exchange. There are three major findings that materialize. Firstly, reliable statistical evidence of a negative relation between the conditional first and second moments of the return distributions of stock prices lends support to the volatility feedback effect. Secondly, ‘feedback’, or momentum-type investors, are not present in this market as is often detected from the daily price changes of other industrialized markets. Finally, trade volume as a proxy for ‘information-driven’ trading suggests that such investors play a statistically significant role in stock price movements. Parameter estimates from this latter group of investors imply that a rise in stock prices from a high volume trading day is more likely than a rise resulting from a low volume trading day.     

Risk A version and Information Structure: An Experimental Study of Price Variability in the Securities Markets

This study investigates the differences in the behaviors between the speculative investors and the conservative investors in two separate experimental markets. Although the market for speculators shows greater price volatility in both bid/ask spread within a trade as well as with intraperiod variances, it exhibits several desirable properties. Specifically, the price patterns tend to converge closer, and at a greater speed to either the prior information equilibrium price or the rational expectation equilibrium price. It also achieves better allocational efficiency. And, it is also less likely to be misled by potentially “false” price information.     

The rapidity of price adjustments to information

This analysis suggests a relationship between the rapidity of price adjustments to information and the accuracy or reliability of the information, as it is perceived by investors. To understand this relationship, we construct a competitive two-person trading game in which investors use an equilibrium strategy to determine their level of investment in information processing. Then, we relate this equilibrium level to the rapidity of price adjustments. The relationship is subtle, however, and in different circumstances the rapidity of price adjustments may increase or decrease as the level of accuracy or reliability of the information changes. In a final section, we argue that aspects of our analysis may be useful for providing a positive theory for the rapidity of price adjustments in a securities market.     

Informed Trading in Stock and Option Markets

We investigate the contribution of option markets to price discovery, using a modification of Hasbrouck's (1995) "information share" approach. Based on five years of stock and options data for 60 firms, we estimate the option market's contribution to price discovery to be about 17% on average. Option market price discovery is related to trading volume and spreads in both markets, and stock volatility. Price discovery across option strike prices is related to leverage, trading volume, and spreads. Our results are consistent with theoretical arguments that informed investors trade in both stock and option markets, suggesting an important informational role for options.     

A Model of Returns and Trading in Futures Markets

This paper develops an equilibrium model of a competitive futures market in which investors trade to hedge positions and to speculate on their private information. Equilibrium return and trading patterns are examined. (1) In markets where the information asymmetry among investors is small, the return volatility of a futures contract decreases with time-to-maturity (i.e., the Samuelson effect holds). (2) However, in markets where the information asymmetry among investors is large, the Samuelson effect need not hold. (3) Additionally, the model generates rich time-to-maturity patterns in open interest and spot price volatility that are consistent with empirical findings.     

The Informational Role of Stock and Option Volume

This article analyzes the intraday interdependence of orderflows and price movements for actively traded NYSE stocks andtheir Chicago Board Options Exchange (CBOE)-traded options.Stock net trade volume (buyer-initiated volume minus seller-initiatedvolume) has strong predictive ability for stock and option quoterevisions, but option net trade volume has no incremental predictiveability. This suggests that informed investors initiate tradesin the stock market but not in the option market. On the otherhand, both stock and option quote revisions have predictiveability for each other. Thus, while information in the stockmarket is contained in both quote revisions and trades, informationin the option market is contained only in quote revisions.