中国个人投资者处置效应研究——一个非理性信念的视角

处置效应是指投资者过早卖出盈利股票而长期持有亏损股票的现象。大量文献表明金融市场投资者存在显著的处置效应,但其产生的原因和机理存在争议。本文在前景理论框架下,构建了包含投资者非理性预期的离散时间投资组合决策模型,发现处置效应随投资者情绪升高而减弱。本文使用我国某券商2007—2009年近177万个人投资者股票账户的交易数据进行了实证分析,得到与理论模型预测的一致结果,即投资者情绪与投资者处置效应之间呈现显著的负相关关系。而且,受情绪影响,投资者处置效应在估值难度较大的股票中更弱。本文结论对理解投资者处置效应、优化投资者卖出决策和加强资本市场基础制度建设具有一定理论和实践意义。     

投资者情绪是导致我国投资者对市场信息出现反应偏差的原因吗：基于贝叶斯分位数回归模型的研究

本文使用贝叶斯分位数回归模型实证分析包含投资者情绪的投资者最优选择模型,结果表明：投资者情绪对于股票收益率存在非线性的正向影响,这是造成投资者对于市场信息出现反应偏差的一个重要原因.同时,市场信息和投资者情绪指标对于我国股票收益率都有着较大的影响作用;当股票出现不同涨跌幅时,市场信息对于股票收益率的影响有着较大的差异性.而考虑了投资者情绪指标之后,投资者对于市场信息的反应偏差明显减小,说明投资者情绪是造成我国投资者对于市场信息出现过度反应和反应不足的重要原因.我国投资者应该树立起良好的投资意识和心态,避免潜在的投资损失.     

Exploring the relationship between investor sentiment and price volatility

By performing Grey relation analysis, this study elucidates the relationship between investor sentiment and price volatility in the Taiwanese stock market. A sequential relationship is identified between investor sentiment and price volatility, and ranked according to order of importance. Analytical results show that short sales volumes may be an individual leading indicator useful in observing the effects of sentiment on price volatility, followed by open interest put/call ratios and trading volumes, and buy/sell orders. Institutional investors are related, to a lesser extent, to price volatility and sentiment. Qualified foreign institutional investors, or more rational investors, are the least influenced by price volatility, followed by securities investment trust companies and dealers. TAIEX options exert the strongest influence on sentiment during the study period, making them a valuable reference for gauging price volatility.     

The effect of suppliers' corporate social responsibility concerns on customers' stock price crash risk

We investigate the spillover effect of corporate social responsibility (CSR) concerns along the supply chain. We propose an information incorporation effect for whether suppliers' CSR concerns affect customers' stock price crash risk. Customers' investors can incorporate information about suppliers' CSR into stock price valuations, lowering the probability of abrupt stock price crashes. Our findings support the information incorporation effect. Suppliers' CSR concerns are negatively associated with customers' stock price crash risk. The negative relationship is more pronounced for firms with high media coverage, negative media sentiment, high investor attention, negative investor sentiment, low trade policy uncertainty, and low political uncertainty. Moreover, we rule out the alternative explanation that suppliers' CSR strengths dominate the effect. Our main finding is supported by change analysis and robustness tests, including an alternative measure test.     

Beliefs regarding fundamental value and optimal investing

Standard optimal portfolio selection models take no account of the special information that active investors believe they possess. For example, active investors who believe they can place bounds on the price of a security will want to use that information when assessing risk and expected return in order to construct an optimal portfolio. In this paper, we use two continuous-time models to analyze how placing boundaries on the price of a stock affects assessed risk, expected returns, and the optimal holdings of an active investor, and how those vary as a function of the relation between the stock price and the boundaries. In particular, the optimal strategy takes significant long/short positions as the price nears its lower/upper boundary.     

股价与中国上市公司投资——盈余管理与投资者情绪的交叉研究

本文考虑到中国证券市场代理问题及信息不对称严重和投资者非理性状况共存的特征,将盈余管理与投资者情绪结合起来分析两者对股价的影响,进而分析两者与中国上市公司投资的关系。通过划分平静时期和动荡时期,本文发现在不同的时期里,盈余管理与投资者情绪导致的错误定价关系两者趋势并不总是一致;盈余管理和投资者情绪在不同时期里分别主导着股价与公司投资的关系;而且在不同时期里,融资约束和换手率对所研究问题的影响也是不同的。     

Sentiment stocks

To study how investor sentiment at the firm level affects stock returns, we match more than 58 million social media messages in China with listed firms and construct a measure of individual stock sentiment based on the tone of those messages. We document that positive investor sentiment predicts higher stock risk-adjusted returns in the very short term followed by price reversals. This association between stock sentiment and stock returns is not explained by observable stock characteristics, unobservable time-invariant characteristics, market-wide sentiment, overreaction to news, or changing investor attention. Consistent with theories of investor sentiment, we find that the link between sentiment and stock returns is mainly driven by positive sentiment and non-professional investors. Finally, exploiting a unique feature of the Chinese stock market, we are able to isolate the causal effect of sentiment on stock returns from confounding factors.     

Islamic and conventional portfolios optimization under investor sentiment states: Bayesian vs Markowitz portfolio analysis

This paper investigates the portfolio optimization under investor’s sentiment states of Hidden Markov model and over a different time horizon during the period 2004–2016. To compare the efficient portfolios of the Islamic and the conventional stock indexes, we have employed two approaches: the Bayesian and Markowitz mean-variance. Our findings reveal that the Bayesian efficient frontier of Islamic and conventional stock portfolios is affected by the investor’s sentiment state and the time horizon. Our findings also indicate that the investor’s sentiment regimes change the Islamic and the conventional optimal diversified portfolios.Moreover, the results show that the potential diversification benefits seem to be more important when using the Bayesian approach than when applying the Markowitz approach. This finding is valid for the bearish, depressed, bullish and calm states in Islamic stock markets. However, the diversification of potential portfolios is significant only for the bullish and the bubble states in the conventional financial markets.The findings of the study provided additional evidence for investors to exploit googling investor sentiment states to evaluate the portfolio performance and make an optimal portfolio allocation.     

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.     

新股发行机制、投资者乐观情绪与IPO高抑价

固定价格、累计投标询价和拍卖发行机制下的IPO抑价模型可解释我国新股发行市场长期存在的高抑价现象:散户投资者对新股发行的乐观情绪会推高二级市场的IPO交易价格,但却不能在IPO发行定价中得到完全体现。单纯通过变革新股发行机制并不能够从根本上抑制IPO高抑价产生,只有疏导散户投资者的乐观情绪才能彻底解决IPO高抑价问题,权宜之策是将散户投资者的乐观情绪嵌入IPO发行定价之中以消除IPO高抑价现象,允许散户投资者参与询价可以有效缓解这一现象,且具有可操作性。     

Investor sentiment and firm capital structure

We provide novel evidence of the role of investor sentiment in determining firms' capital structure decisions from three perspectives: leverage ratio, debt maturity and leverage target adjustment. We find that when investor sentiment is high, firms increase their leverage ratios, supporting our contention that high investor sentiment increases firms' debt capacity and facilitates the use of an aggressive leverage policy. Debt maturity is shorter in high sentiment periods, implying that firms are confident about future earnings and use shorter debt maturity to signal their financial solvency. Leverage target adjustment is slower in low sentiment periods, indicating higher costs of external finance. Furthermore, the sentiment-leverage relationship sensitivity is greater for financially constrained firms. Our extended analysis determines that leverage-increasing firms generate lower stock returns subsequent to a period of high sentiment, offering practical insights into the economic consequences of increasing leverage in high sentiment periods on corporate value for investors. Our research advances the understanding of the impact of investor sentiment on firms' financing decisions and stock returns.     

LONG-TERM STOCK PRICE REVERSALS IN THE UK: EVIDENCE FROM REGRESSION TESTS

This paper seeks to advance our knowledge about the UK evidence on long-term stock price reversals. Many of the major studies of long-term reversals have been done using US data, prompting fears about data snooping biases. There have been comparatively few UK studies and they have all employed contrarian portfolio techniques to identify evidence of reversals. None of these UK studies has used cross-section regression tests, which have been employed in some of the US investigations, and this paper aims to fill this gap. We find evidence of stock price reversals, even after controlling for time-varying risk and restricting the study to larger, UK-listed companies—that is, companies that are frequently traded, more heavily regulated and extensively analysed by market commentators, analysts and institutional investors.     

Divergence of sentiment and stock market trading

This paper introduces the concept of divergence of sentiment to the behavioral finance literature. We measure the distance between people with positive and negative sentiment on a daily basis for 20 countries by using data from status updates on Facebook. The prediction is that a higher divergence of sentiment leads to more diverging views on prospects and risks, and thus to more diverging views on the value of a stock. In line with this prediction, divergence of sentiment is positively related to trading volume. We further predict and find a positive relation between divergence of sentiment and stock price volatility. The observed relations are stronger when individual investors are more likely to trade. We compare the effect of our country-specific measures to a global measure of divergence of sentiment. We find that the separate effects of country-specific and global divergence measures depend on a country's level of market integration.     

Does the location of stock exchange matter? A within-country analysis

The current study documents an interesting phenomenon that retail investors prefer to invest in stocks listed at the stock exchange that is geographically close to them in China. This pattern is robust when we control for the well-documented local bias within a country. Among companies with similar distances to both stock exchanges and companies headquartered locally, investors still display a strong tendency to invest in locally-listed stocks. Among stocks with similar distances to both stock exchanges, those listed in Shanghai (Shenzhen) co-move more in returns and trading volumes, with the benchmark at the Shanghai (Shenzhen) stock exchange. Such a preference for local exchange seems not to be motivated by information advantage, because investors do not obtain abnormal returns from their trades on stocks listed nearby. Our findings provide additional evidence that non-information-based familiarity bias induces investment and that such investor bias and exchange-level sentiment influence asset price formation.     

Investor sentiment and return predictability of disagreement

This study examines the influence of investor sentiment on the relationship between disagreement among investors and future stock market returns. We find that the relationship between disagreement and future stock market returns time-varies with the degree of investor sentiment. Higher disagreement among investors’ opinions predicts significantly lower future stock market returns during high-sentiment periods, but it has no significant effect on future stock market returns during low-sentiment periods. Our findings imply that investor sentiment is related to several causes of short-sale impediments suggested in the previous literature on investor sentiment, and that the stock return predictability of disagreement is driven by investor sentiment. We demonstrate that investor sentiment has a significant impact on the stock market return predictability of disagreement through in-sample and out-of-sample analyses. In addition, the profitability of our suggested trading strategy exploiting disagreement and investor sentiment level confirms the economic significance of incorporating investor sentiment into the relationship between disagreement among investors and future stock market returns.     

Individual Investors' Sentiment and Temporary Stock Price Pressure

Using data for the Hong Kong stock market, where individual investors' sentiment is likely to be influential, this study finds that the publication of individual investors' sentiment temporarily affects stock prices regardless of the publication's incompetence in predicting stock returns. Specifically, when the publication reports that more and more investors are optimistic, the return on the day just after the publication is higher and the return several days later is lower. Furthermore, the results are strongest for small stocks, and weakest for large stocks. It seems that some individual investors buy (sell) stocks when others, as reported by the publication, are optimistic (pessimistic), and that the trading causes temporary buying (selling) pressure initially and price reversals afterwards.     

eInformation: A Clinical Study of Investor Discussion and Sentiment

We examine the information flow for four stocks over seven months to trace the relationship between on-line discussion, news activity, and stock price movements. On-line discussions support numerous unsubstantiated rumors, substantial on-point exchanges, and quick dissemination of imminent and recently released information. Applying language-processing routines to message board postings and news, we create sentiment and disagreement measures or "eInformation." We analyze the determinants of sentiment and disagreement, and trace links between news, eInformation, and stock returns. This intensive clinical study of on-line discussions suggests mechanisms individual investors and groups can use to analyze and digest company information.     

Do the diversification choices of individual investors influence stock returns?

This paper shows that the diversification choices of individual investors influence stock returns. A zero-cost portfolio that takes a long (short) position in stocks with the least (most) diversified individual investor clientele generates an annual, risk-adjusted return of 5–9%. This spread reflects the combined effects of sentiment-induced mispricing, narrow risk framing, and asymmetric information, where the sentiment effect is the strongest. Furthermore, the influence on returns is stronger among smaller, low institutionally owned, and hard-to-arbitrage stocks. These results are robust to concerns about relatively short sample size, improper factor model specification, slow information diffusion, and high transactions costs.     

透视中国上市公司的“迎合投资”行为

采用2003～2008年中国沪深股票市场的A股上市公司作为研究样本,在市场非理性背景下研究投资者情绪对上市公司投资行为的影响。区分市场情绪低落和高涨时期,发现只有在市场情绪高涨时期公司投资才对投资者情绪敏感;而在市场情绪低落时期,上市公司通过盈余管理导致错误定价配合公司投资决策。作为投资者短视代表的换手率对上市公司迎合投资行为的影响呈倒U型,说明并不是换手率越高,公司投资对投资者情绪的迎合越明显。     

Takeover vulnerability and the behavior of short-term stock returns

This paper proposes and tests the hypothesis that takeover vulnerability contributes to short-term price reversal by motivating investors to trade speculatively and also by making investors demand immediacy in their trades. That is, takeover vulnerability is hypothesized to amplify two channels of short-term price reversal, namely, overreaction and price concession. Using several different measures of takeover vulnerability, we find that takeover vulnerability is positively related to price reversal at daily frequencies. We also find that their positive relation is more pronounced when the stock is illiquid or when it is costly to arbitrage, a finding that is consistent with the notion that the observed price reversal is driven by the earlier price concession or overreaction. While unable to determine the exact relative importance between the two channels, we conduct further analysis showing that each channel plays an independent role. Finally, we find no relation between takeover vulnerability and price reversal at the portfolio level, which means that the price reversal observed in individual stock returns is driven by a firm-specific component.