Herding and Contrarian Behavior in Financial Markets

Rational herd behavior and informationally efficient security prices have long been considered to be mutually exclusive but for exceptional cases. In this paper we describe the conditions on the underlying information structure that are necessary and sufficient for informational herding and contrarianism. In a standard sequential security trading model, subject to sufficient noise trading, people herd if and only if, loosely, their information is sufficiently dispersed so that they consider extreme outcomes more likely than moderate ones. Likewise, people act as contrarians if and only if their information leads them to concentrate on middle values. Both herding and contrarianism generate more volatile prices, and they lower liquidity. They are also resilient phenomena, although by themselves herding trades are self‐enforcing whereas contrarian trades are self‐defeating. We complete the characterization by providing conditions for the absence of herding and contrarianism.     

羊群效应与内幕信息的揭示分析

本文用金融市场微观结构模型的序贯交易框架分析了证券市场上的多维不确定性怎样引起投资者的羊群交易行为。结论表明当市场上存在事件不确定和信息精度不确定时,投资者之间可能发生羊群行为,这种行为会导致内幕信息在一段时间内得不到有效揭示。做市商在发生羊群效应期间虽然只能判断出事件的存在性,而无法学习到内幕信息的好坏和精度,但他仍会继续调整资产的价格并最终结束羊群效应。     

股票分析师的羊群行为对公司股价同步性的影响分析

股价"同涨同跌"是我国股票市场的一种重要现象。多股集体"暴跌"会给公司和投资者造成严重的损失,因而股价同步性的问题受到监管者和学术界的广泛关注。本文以2010-2017年股票分析师对上市公司做出的预测为主要研究对象,验证了股票分析师的羊群行为与公司股价同步性间的关系,讨论了机构投资者和市场情绪的作用机制。实证结果表明我国股票分析师的羊群行为是"非信息驱动"的真羊群行为,这种行为降低了市场上的特质信息含量,从而增加了公司的股价同步性。上述关系在熊市中更为显著,并且分析师与机构投资者之间的利益冲突会加剧其羊群行为对股价同步性的影响。本文的研究对理解如何降低股价崩盘风险、提高我国股票市场的信息传递效率具有十分重要的理论和实践意义。     

网络近邻择优策略下的股市羊群行为演化模型及仿真

以行为金融理论和复杂网络理论为基础,针对股市投资者行为的"模仿"性特征,从投资者自我心理偏好和近邻行为效应两个维度,构建网络近邻择优策略下的股市羊群行为演化模型,理论分析股市羊群行为的演化动力学特征,并进行模拟仿真。研究结果表明:投资者投资行为演化路径受股市网络结构和近邻择优效应影响;近邻择优函数的凹凸性直接关系投资者投资行为动力学均衡态的稳定性;股市网络连通度和异质性对投资者投资行为均衡演变趋势具有重要作用;初始投资行为状态特征对投资者投资行为均衡态影响较小。所建立的模型及分析结论在一定程度上阐述了影响股市投资者投资行为变化的特征要素,解释了股市羊群行为演变的内在性规律,为金融管理部门制定宏观政策起到了一定理论支撑。     

基于LSV模型的机构与个人羊群行为研究

超常规发展机构投资者并未有效抑制市场波动,侵害中小投资者利益的现象时有发生。为探究中国证券市场的投资者羊群倾向究竟是机构投资者还是个人投资者,本文使用2006年至2016年Wind数据库中年均950家所有可验证的机构数据以及某券商年均40万条个人交易数据,运用LSV模型对投资者羊群行为进行检验,并比较机构投资者与个人投资者的行为差异。在结合投资者发展结构和十年间的市场波动特征后研究发现,无论是公募基金、保险公司、券商、社保基金还是QFⅡ等机构投资者,均具有比个人投资者更显著的羊群效应,个人投资者中仅"大户"在部分年间显示出一定的羊群倾向。研究还创新性地发现了公募基金羊群倾向的季度波动效应,表现为一、三季度和二、四季度的明显差异,且振幅逐年加剧;保险公司的投资行为则趋于成熟缓和。     

中国股评家的羊群行为研究

鉴于中国股评家在证券市场中的特殊地位和羊群行为在我国证券市场中广泛存在且对 市场的效率有重要影响等情况,建立了中国股评家大盘预测的羊群行为的检验模型,分别研究 股评家羊群行为的存在性、影响羊群行为的因素和羊群行为的理性特征. 主要结论为:股评家 对舆论有明显的羊群行为;当历史收益率增加、市场乐观情绪高涨、股评家预测的一致程度增 加、股评家的能力降低、股评家的初始声誉增大时,股评家参与羊群行为的动机增加. 股评家羊 群行为的理性研究指出,当舆论被事后的收益率证明为错误时,羊群行为反而增加. 因此股评 家的羊     

基于非理性行为的羊群效应分析:一个简单模型

本文在序贯交易的框架内用一个简单的模型分析了证券市场上的非理性交易行为怎样引起交易者之间的羊群行为。研究结论表明:若证券市场上所有的参与者完全理性且风险中性,则市场上不会出现羊群交易行为;相反,即便在一维不确定性下,交易者的非理性交易行为可能引起羊群效应。     

AN ANALYSIS OF BEHAVIOR AND PERFORMANCE IN THE FOOD RETAILING INDUSTRY USING EXPERIMENTAL BUSINESS GAMING

This research tested hypotheses concerning the effects of organizational affiliation, differences among managers nested within organizational affiliation, degree of price competition and selected demographic and psychological traits of managers on economic behavior and performance. Experimental gaming in a behavioral science laboratory was used with a group of 60 subjects who were managers of Indiana supermarkets. The results support the influence of economic factors on the behavior and performance of managers. Degree of price competition imposed by the researchers significantly affected pricing decisions. At the same time, factors not usually considered in the static theory of the firm, such as organizational affiliation, had a significant influence on behavior and performance. While psychological and demographic traits generally did a poor job of explaining manager behavior, their effect may have been masked by the main treatments to which subjects were exposed. Realism in the experiment was not as high as expected, but the approach used was judged to be superior to alternative approaches.     

OPTIMAL MONETARY POLICY AND FINANCIAL STABILITY IN A NON‐RICARDIAN ECONOMY

I present a model with discontinuous asset‐market participation (DAMP), where all agents are non‐Ricardian, and where heterogeneity among market participants implies financial‐wealth effects on aggregate consumption. The implied welfare criterion shows that financial stability arises as an additional and independent target, besides inflation and output stability. Evaluation of optimal policy under discretion and commitment reveals that price stability may no longer be optimal, even absent inefficient supply shocks: some fluctuations in output and inflation may be optimal as long as they reduce financial instability. Ignoring the heterogeneity among market participants may lead monetary policy to induce substantially higher welfare losses.     

基于动态无标度网络的信息策略与羊群行为演化研究

传统的人工股票市场效率不高,对投资者的异质性假设缺乏经济学含义,更没有考虑市场中广泛存在的羊群行为的影响。本文以国外期权市场异质信息交易者模型为基础,结合互联网金融特点在传统人工股票市场中引入异质信息策略与动态无标度人际关系网络刻画的羊群行为构建出新的人工股市模型,进行投资者的信息策略与羊群行为演化研究,对比分析不同机制的引入所带来的影响,揭示动态关系网络环境下信息策略演化结果。研究发现：一方面,信息策略演化机制的引入加快了市场均衡速率并提高了市场效率,同时也大大降低了投资者财富水平并拉大了财富差距;信息策略与羊群行为的演化并不会导致投资者完全向内幕信息交易者聚集,高、低信息档次投资者明显居多且其他信息档次投资者仍然存在。另一方面,动态关系网络下羊群行为的引入增强了投资者的被传染程度,并进一步缩小了财富差距且显著提高了内幕信息的扩散质量与效率。所以,互联网关系网络环境下高、低信息档次投资者占据相对优势,但其他信息档次投资者并不会被挤出市场;监管部门在努力寻求高市场效率的同时,也应在投资者财富与社会总财富等方面进行适当权衡。     

网络传染是“真羊群”还是“伪羊群”?——网络传染程度对资本市场定价效率的影响

基金经理在选股时是否具有独立性以及是否能发挥其专业职能发掘更多企业特质信息对基金经理能力评估以及稳定我国资本市场具有重要意义。为研究基金经理在重仓股配置上的网络传染现象是否能向市场传递企业特质信息进而提高定价效率，本文以我国2006年至2018年开放式基金季度数据为样本，构建了一种新型的投资关系网络—"基金持仓变动相似性多值符号网络"，研究了残差网络聚类系数与股价同步性的关系。研究结果表明，当前我国基金经理在重仓股的选择和资金配置上具有较强的模仿关系和稳定的相似性网络结构，基金持仓变动相似性网络中不存在私有信息和行业信息传递，网络传染现象降低了市场的定价效率。本文研究结论对有效识别基金经理的羊群行为以及防范相关风险等具有重要的理论和现实意义。     

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)     

Decision Making and the Price Setting Newsvendor: Experimental Evidence

We present an experimental study of the price‐setting newsvendor problem, which extends the traditional framework by allowing the decision maker to determine both the selling price and the order quantity of a given item. We compare behavior under this model with two benchmark conditions where subjects have a single decision to make (price or quantity). We observe that subjects deviate from the theoretical benchmarks when they are tasked with a single decision. They also exhibit anchoring behavior, where their anchor is the expected demand when quantity is the decision variable and is the initial inventory level when price is the decision variable. When decision makers set quantity and price concurrently, we observe no significant difference between the normative (i.e., expected profit‐maximizing) prices and the decision makers’ price choices. Quantity decisions move further from the normative benchmarks (compared to when subjects have a single decision to make) when the ratio of cost to price is less than half. When this ratio is reversed, there is no significant difference between order levels in single‐ and multi‐task settings. In the multidecision framework, we also observe a tendency to match orders and expected demand levels, which subjects can control using prices.     

Understanding Mechanisms Underlying Peer Effects: Evidence From a Field Experiment on Financial Decisions

Using a high‐stakes field experiment conducted with a financial brokerage, we implement a novel design to separately identify two channels of social influence in financial decisions, both widely studied theoretically. When someone purchases an asset, his peers may also want to purchase it, both because they learn from his choice (“social learning”) and because his possession of the asset directly affects others' utility of owning the same asset (“social utility”). We randomize whether one member of a peer pair who chose to purchase an asset has that choice implemented, thus randomizing his ability to possess the asset. Then, we randomize whether the second member of the pair: (i) receives no information about the first member, or (ii) is informed of the first member's desire to purchase the asset and the result of the randomization that determined possession. This allows us to estimate the effects of learning plus possession, and learning alone, relative to a (no information) control group. We find that both social learning and social utility channels have statistically and economically significant effects on investment decisions. Evidence from a follow‐up survey reveals that social learning effects are greatest when the first (second) investor is financially sophisticated (financially unsophisticated); investors report updating their beliefs about asset quality after learning about their peer's revealed preference; and, they report motivations consistent with “keeping up with the Joneses” when learning about their peer's possession of the asset. These results can help shed light on the mechanisms underlying herding behavior in financial markets and peer effects in consumption and investment decisions.     

ON THE STABILITY OF DIFFERENT FINANCIAL SYSTEMS

An economy in which deposit‐taking banks of a Diamond and Dybvig style and a financial market coexist is modeled in a simple framework closely related to Diamond (1997). Solely depending on the fraction of naïve households who cannot efficiently invest directly in the corporate sector, two different types of financial systems emerge. With the fraction comparatively low, the evolving financial system can be interpreted as market‐oriented, whereas a high fraction brings about a bank‐dominated financial system. In market‐oriented systems, banks only provide naïve households with access to efficient investments; in bank‐dominated systems, banks' deposit contracts also offer some degree of liquidity insurance. Consequently, compared to market‐oriented financial systems, the household sector in bank‐dominated financial systems holds a larger portfolio fraction in deposits and a smaller part in direct investments. Analyzing the resilience of the different financial systems to various types of shocks shows that moderately bank‐dominated (or hybrid) financial systems are particularly fragile, because only in these systems do fire sales of assets by distressed banks cause a deterioration in asset prices that also precipitates other banks into crisis. (JEL: D52, E44, G10, G21)     

THE ROLE OF TRANSACTION COSTS FOR FINANCIAL VOLATILITY: EVIDENCE FROM THE PARIS BOURSE

This paper analyzes the causal linkage between transaction costs and financial volatility under two methodological improvements over the existing literature. First, we use panel data in which exogenous transaction cost differences in the French stock market are induced by price level dependent minimum price variation rules (tick size rules). Unlike in previous studies based on one‐time regulatory tick size changes (like the U.S. decimalization), we can separately identify and control for marketwide volatility changes. Second, we avoid the pitfalls of biased volatility measurement across regimes by using the range as a tick size robust volatility metric. Panel regressions controlling for marketwide volatility effects show at high levels of statistical significance that the hourly range volatility of individual stocks increases by more than 30% for a 20% exogenous increase in transaction costs due to tick size variations in the French trading system. In the light of this evidence, higher transaction costs in general, and security transaction taxes in particular, should be considered as volatility increasing. (JEL: F3, G1, G14)     

体验型产品消费行为的羊群效应及机理研究——基于电影行业消费行为的实证解释

互联网环境下消费者购买体验型产品时对网络信息的依赖性很大。因此，研究社交媒体影响下体验型产品的消费者决策选择行为具有现实意义。本文以电影行业的票房偏离及消费跟风现象为切入点，探究体验型产品的羊群效应并对其产生的内在机理进行解释。采集艺恩资讯的票房数据以及豆瓣的电影基本信息及影评等数据作为研究样本，从消费者"羊群行为"视角分析其对电影票房的影响。研究发现：在控制了质量等内生性影响之后，消费者羊群效应依然存在；产品特征信息对羊群效应起到了调节作用，从而形成理性跟随；采用预期差异模型可以解释消费者实现理性跟随的过程。研究结论对于电影行业宏观政策制定及对体验型产品合理进行营销推广提供了理论基础与实证依据。     

基于Copula模型的商业银行碳金融市场风险整合度量

目前低碳经济已经成为转变经济发展方式的战略措施之一, 碳金融业务逐渐成为金融机构助力低碳经济发展的重要金融创新领域, 而风险控制问题始终是影响金融创新成败的关键。目前中国的碳金融市场以清洁发展机制(CDM)下商业银行参与的间接金融为主导, 商业银行参与碳金融业务面临国际碳价波动、碳交易结算货币汇率波动等诸多风险, 且多源风险因子之间具有业务共生性和复杂相关性。论文选取2009-2012年美国洲际交易所(ICE)的核证减排量CERs期货价格和欧元兑人民币汇率价格作为金融时间序列的样本数据, 探究运用ARMA-GARCH模型分别刻画碳价风险和汇率风险特性的方法, 研究处理风险因子间的非线性相关关系的Copula函数方法, 构建Copula-ARMA-GARCH模型并利用Monte Carlo模拟计算碳市场多源风险的整合VaR。实证发现:碳金融市场收益率具有波动聚集性和异方差特性;潜在的碳价风险要高于汇率风险;若忽视不同风险因子之间的相关性会高估碳市场风险;政府汇率监管在一定程度上降低了碳市场的风险。研究贡献在于探究符合碳金融资产风险特征的多源风险整合度量技术, 为商业银行有效控制碳市场风险、促进碳金融创新提供理论依据。     

竞争中的参考价格效应及承诺

消费者的社会感知会影响其对产品和品牌的评价。当消费者进行购买选择时,经常会受到参考价格效应的影响。而广告和价格不仅是企业经常要考虑的重要决策,还会对参考价格产生重要影响。为此,一个值得研究的的问题是：在考虑参考价格效应的情况下,企业该怎样确定其动态广告和价格策略？
为了研究该问题,本文构建了一个广告和价格的动态模型,来研究一个双寡头市场环境下两个寡头企业的价格和广告决策,并以此分析参考价格效应的作用。具体而言,我们假定企业可以采用广告承诺和价格承诺中的一种,其中前者承诺其在一段时间内的广告投入量恒定不变,而后者确保价格不变。两种策略不仅会影响消费者的购买决策,也会影响竞争对手的选择。在上述假定下,我们探讨了两个寡头企业在都采用广告承诺、都采用价格承诺及一个企业采用广告承诺而另一个企业采用价格承诺等三种不同情形下的最优广告和价格决策,并以此分析了三种情形下参考价格效应对最优的广告投入及定价策略的影响。最后,通过数值分析,探讨了不同情形下企业的最优策略选择。     

On the Advantage of Quantity Leadership When Outsourcing Production to a Competitive Contract Manufacturer

This study investigates a supply chain comprising an original equipment manufacturer (OEM) and a contract manufacturer (CM), in which the CM acts as both upstream partner and downstream competitor to the OEM. The two parties can engage in one of three Cournot competition games: a simultaneous game, a sequential game with the OEM as the Stackelberg leader, and a sequential game with the CM as the Stackelberg leader. On the basis of these three basic games, this study investigates the two parties' Stackelberg leadership/followership decisions. When the outsourcing quantity and wholesale price are exogenously given, either party may prefer Stackelberg leadership or followership. For example, when the wholesale price or the proportion of production outsourced to the CM is lower than a threshold value, both parties prefer Stackelberg leadership and, consequently, play a simultaneous game in the consumer market. When the outsourcing quantity and wholesale price are decision variables, the competitive CM sets a wholesale price sufficiently low to allow both parties to coexist in the market, and the OEM outsources its entire production to this CM. This study also examines the impact of the supply chain parties' bargaining power on contract outcomes by considering a wholesale price that is determined via the generalized Nash bargaining scheme, finding a Stackelberg equilibrium to be sustained when the CM's degree of bargaining power is great and the non‐competitive CM's wholesale price is high.