基于高频数据的我国股市羊群效应研究

行为金融理论将投资者受自身心理因素、其他投资者的交易行为和外部环境等影响而表现出的跟风投资行为称为羊群行为，大量个体的羊群行为现象被称为羊群效应。虽然羊群效应短期内增强了股票的流动性，但易导致股价严重偏离潜在价值，诱发股价异常波动、股市崩盘，甚至股灾。文章基于2018年我国453个股指的分时高频数据，建立CCK模型，研究发现：我国股市存在短期、非对称的非理性羊群效应。基于此，提出提高股市定价效率和促进市场平稳运行的建议。     

个体投资者自尊与羊群行为:特质愤怒和他人评价的作用

以个体投资者为研究对象,本研究基于个体内部异质性和外部决策情境相整合的视角,构建了一个被调节的中介作用,以探讨自尊与羊群行为的关系以及特质愤怒和他人评价在其中的作用。研究结果表明,自尊对特质愤怒、羊群行为均有显著负向影响;特质愤怒在自尊与羊群行为间起中介作用;他人评价对特质愤怒与羊群行为间关系以及对自尊通过特质愤怒影响羊群行为的间接效应均具有调节作用,无他人评价时特质愤怒在自尊对羊群行为负向影响中具有完全中介效应,该中介作用在存在他人评价时变得不显著。这些结论对于我国建设理性投资者队伍、开展投资者教育实践具有启示作用。     

中国证券投资基金羊群行为:基于LSV模型的实证研究

本文运用LSV及其修正模型,采用2003年以来的开放式基金数据,分析了我国基金羊群行为状况.研究发现,开放式基金存在较明显的羊群行为,与国外市场相比,中国市场上开放式基金的从众程度更高,羊群效应显著;而且大部分时间里,我国资本市场上羊群效应随参与交易的基金数目的增加而增强.另外,本文还按照股票市场上市时间、股票市值大小等特征考察了投资基金羊群行为.     

中国证券投资基金羊群行为:基于LSV模型的实证研究

本文运用LSV及其修正模型,采用2003年以来的开放式基金数据,分析了我国基金羊群行为状况。研究发现,开放式基金存在较明显的羊群行为,与国外市场相比,中国市场上开放式基金的从众程度更高,羊群效应显著;而且在大部分时间里,我国资本市场上羊群效应随参与交易的基金数目的增加而增强。另外,本文还按照股票市场上市时间、股票市值大小等特征考察了投资基金羊群行为。     

我国机构投资者的“羊群行为”分析

机构投资者存在羊群行为已经成为学术界的共识。但是对我国股票市场机构投资者的羊群行为实质以及对证券市场稳定性有何影响众说纷纭。在研究机构投资者的羊群行为的实证基础上,本文阐述羊群行为存在的原因及其对证券市场的影响。     

中国股市个体投资者羊群行为影响因素分析

中国股市投资者表现出显著的羊群行为,心理因素是投资者羊群行为产生的主要原因,情绪、股票历史收益率和股票规模等也是影响投资者行为的重要因素。本文利用我国股市个体投资者交易数据,对影响投资者羊群行为的因素进行了实证研究,探讨了我国股市个体投资者羊群行为的特征。     

我国上海期货市场羊群效应实证分析

羊群行为是造成金融市场剧烈波动的一种非理性行为,这种行为的存在与否对于期货市场价格的稳定性至关重要。本文在归纳总结学者们研究方法和模型的基础上,着重运用CCK模型对我国上海期货市场是否存在羊群效应进行实证检验,结果发现我国上海期货市场整体上存在着羊群效应,在市场上涨时投资者羊群效应更加明显,“追涨”效果明显大于“杀跌”效果。     

P2P网络借贷的羊群行为及其信息驱动

我国互联网金融投资者面临的骗局和连锁风险,是否是互联网金融羊群行为的必然结果呢?如何建构互联网金融的监管制度,才能在不影响互联网金融融资效率前提下降低互联网金融的风险呢?在改进的MNL模型基础上,通过研究我国P2P网络借贷羊群行为的性质及其背后的信息驱动,回答上述问题。研究结果显示,我国P2P网络借贷市场上存在着理性的羊群行为;其背后的信息驱动因素依次为平台信息、项目信息和借款人信息。因此,我国网络借贷市场不会由于投资者羊群行为引发市场风险,互联网金融监管机制的重点在于,强化投资者保护、完善和统一P2P网络借贷平台的信用评估和披露制度。     

中国机构投资者投资行为的异化

在我国机构投资者迅猛发展的同时,其投资行为也在发生异化,与政府和市场的最初预期产生明显的偏羞。机构投资者投资行为的异化典型地表现为：短视行为、羊群行为、处置效应和违法违规行为。机构投资者投资行为的异化严重扰乱了证券市场的正常秩序,加剧了市场风险的累积。中国证券市场的非理性波动其实并非由非理性的个人投资者所引起,而正是由行为相对更为“理性”的机构投资者（他们构成了庄家的大部分）所引起。     

机构投资者自利性行为对次贷危机的诱导机制研究

本文详细分析了机构投资者在次贷危机中的自利性行为表现,探讨了机构投资者的传导机制作用。通过研究发现,机构投资者的产品包装与推销的行为为次贷危机的爆发提供了"物质基础",为危机的爆发埋下隐患;而随后机构投资者的追逐购买和跌价抛售的投机行为,严重的影响了资本市场的流动性;而机构投资者固有的"羊群行为"的效应,进一步加剧了市场的波动,诱导次贷危机的最终爆发。     

Individual and institutional herding and the impact on stock returns: Evidence from Taiwan stock market

Using high frequency intraday data, this paper investigates the herding behavior of institutional and individual investors in the Taiwan stock market. The study finds evidence of herding by both investors but a stronger herding tendency among institutional than among individual investors. Institutional investors herd more on firms with small capitalizations and lower turnovers and they follow positive feedback strategies. The portfolios that institutional investors herd buy outperform those they sell by an average of 1.009% during the 20 days after intense trading episodes. By contrast, individual investors herd more on firms with small sizes and higher turnovers, and they crowd to buy (sell) stocks with negative (positive) past returns. The portfolios that individual investors herd buy underperform those they sell by an average of − 0.829% during the following 20 days. Moreover, these return differences of both investors are more pronounced under a market with higher pressure and among small stocks. These findings suggest that the herding of institutional investors speeds up the price-adjustment process and is more likely to be driven by correlated private information, while individual herding is most likely to be driven by behavior and emotions.     

中国机构投资者与市场稳定性研究

文章从机构投资者的投资行为出发,检验中国机构投资者是否存在羊群行为和正反馈交易,并且分析检验了在剔除宏观经济影响之后,机构投资者行为对市场稳定性的影响。检验结果表明,机构投资者存在较明显的羊群行为和正反馈交易行为,且羊群行为显著加剧股票波动。最后,针对研究结论本文提出了相应的政策建议。     

The trading behavior of foreign,domestic institutional,and domestic individual investors: Evidence from the Taiwan stock market

In this paper, we apply the threshold cointegration model of Hansen and Seo (2002), incorporating differences in the nonlinear behavior of investors across regimes. An examination of the trading behavior of foreign, domestic institutional, and domestic individual investors in Taiwan revealed no predominance among the three types of investors. When the market was near equilibrium, the purchases of domestic individual investors positively impacted stock prices. This finding, which is consistent with Choe et al. (2005), suggests that domestic individual investors have an edge in investment performance over other types of investors. However, when the market departed substantially from equilibrium, the purchases of foreign and domestic institutional investors predicted a rise in stock prices. On the other hand, domestic individuals traded at worse stock prices; these prices tended to fall (rise) after the purchase (sale).     

Institutional herding in international markets

This paper studies herding behavior of institutional investors in international markets. First, we document the existence of wide-spread herding in 41 countries (referred to as “target countries” hereafter) in the sample. We then examine the relation between contemporaneous institutional demand and future returns and find that institutional herding stabilizes prices. Next, we examine the relation between institutional investors’ herding behavior and the level of information asymmetry in the target countries. We measure the degree of information asymmetry in each target country along five dimensions: (1) stock market development, (2) ease of access to information, (3) corporate transparency, (4) investor rights, and (5) macroeconomic factors that relate to the information environment. We find evidence that institutional investors herd more in markets characterized by low levels of information asymmetry (high level of information transparency). This result suggests that institutional investors’ herding behavior is likely driven by correlated signals from fundamental information. Lastly, we show that price adjustment is faster in informationally transparent markets.     

Who is the more overconfident trader? Individual vs. institutional investors

Guided by the Gervais and Odean (2001) overconfident trading hypothesis, we comprehensively investigate the trading behavior of individual vs. institutional investors in Taiwan in an attempt to identify who is the more overconfident trader. Conditional on the various states of the market, on market volatility, and on the risk level of the securities they trade, we find that both individual and institutional investors trade more aggressively following market gains in bull markets, in up-market states, in up-momentum market states, and in low-volatility market states and that only individual investors trade more in riskier securities following market gains. More importantly, we find that individual investors trade more aggressively following market gains in the three conditional states of the market and in high-volatility market states than institutional investors. Also, individual investors trade more in relatively riskier securities following gains than institutional investors. These findings provide evidence that individual investors are more overconfident traders than institutional investors.     

Does investor sentiment really matter?

We examine the role sentiment plays and its manifestation in the trading behavior of investors in the U.S. stock market. Our findings support the notion that sentiment-induced buying and selling is an important determinant of stock price variation. While ‘classical’ asset pricing categorizes investors who trade in ways not consistent with mean-variance optimization as ‘irrational,’ we show that this traditional view should not hastily be evoked to characterize sentiment-driven investing. We instead show that sentiment-driven investors can trade against the herd and sell when prices are overinflated as a result of over-bullishness and vice versa. The asset pricing implications of this paper are that sentiment is linked to shifts in risk tolerance and this triggers contrarian-type behavior. In sum, we uncover the following regarding the behavior of sentiment-driven investors; firstly, they are more apt to trade on survey-based indicators rather than market-based indicators. Secondly, they trade on the basis of information extracted from individual, rather than institutional, investor surveys. Thirdly, they respond asymmetrically to shifts in sentiment and trade more aggressively during periods of declining sentiment. Finally, there is asymmetry in the role of sentiment with respect to business conditions whereby such buying and selling is more pronounced during bear markets.     

机构投资者与个人投资者过度自信行为比较研究

本文首先基于我国A股市场机构股票持有数据,构建了不同的投资组合来区分机构投资者与个人投资者的投资行为。然后运用Granger因果检验与SUR估计,探讨了我国证券市场机构投资者与个人投资者是否具有过度自信行为,结果表明无论是机构投资者还是个人投资者在不同市场状态下都存在交易过多的过度自信认知偏差。并且我国证券市场上个人投资者与机构投资者的过度自信程度在不同的市场状态下并无明显差异。最后提出了相关政策建议。     

Gender and herding

This study uses a unique dataset from a large anonymous brokerage firm to examine the herding behavior of Chinese individual investors. The empirical evidence reveals that females are more inclined to follow the behavior of ‘same-sex’ investors. Market conditions and stock characteristics affect females and males similarly in that individual investors herd more intensively in the bull market, on stocks with better liquidity and larger market capitalization. We find female investors generally yield lower returns than males when they herd intensively, and this finding is more pronounced during a bull-market period. Outcomes from individual-level herding measurements suggest that portfolio turnover drives the difference in herding between genders.     

Do Qualified Foreign Institutional Investors Herd in Taiwan's Securities Market?

This paper investigates whether and why qualified foreign institutional investors (QFIIs) in Taiwan herd when picking stocks. The evidence shows that QFIIs herd in Taiwan's securities market: They follow each other into and out of the same securities. We identify how the herding behavior forms and how it changes over time. The results suggest that there is an industry effect when QFIIs pick up stocks. They herd on securities classified in specific industries and also prefer stocks with high past returns as well as large firm size, supporting the argument that QFIIs are momentum traders. Characteristic herding and investigative herding explain QFIIs' trading behavior in Taiwan.     

Whose money is smart? Individual and institutional investors’ trades based on analyst recommendations

This study explores how institutional and individual investors respond to analyst recommendations. Using a unique account-level trading dataset taken from the Shanghai Stock Exchange, we obtain direct evidence to show that (1) active institutional investors are significantly net buyers (net sellers) on “strong buy” and “buy” (“hold” and “sell”) recommendations; (2) active institutional investors condition their trades based on the buy-side pressure of analysts; (3) institutional investors earn abnormal returns by incorporating analysts’ buy-side pressure into their trading reactions to analyst recommendations; and (4) individual investors, in contrast, exhibit abnormal trade reactions opposite to those of active institutional investors. Our results are robust to alternative measures and different specifications. This study provides evidence that active institutional investors are more sophisticated processors of information and provides support for regulators’ concerns about the sub-optimal investment decisions made by individual investors who are unaware of the potential conflicts of interest analysts may face.