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。     

基金经理更换、股票联动与股票价格

基金经理更换打破了基金共同持股投资组合中股票的关联性,降低了股票收益率相关性,进而影响了股票价格。本文基于基金共同持股和基金经理更换构建了对冲投资组合,获得0.1%的日超额收益率。基金投资组合中股票收益率相关性能够解释这种超额收益率,本文发现基金更换经理后,新基金经理重建投资组合,打破了原投资组合中股票间的关联,股票收益率相关性减弱,基金共同持股程度高的股票价格受到了更大影响。基金的被动流动性冲击不能解释本文的发现。本文的研究表明基金经理变更等基金管理行为通过股票收益率相关性对股票价格产生了重要影响。     

Intraday Price Change and Trading Volume Relations in the Stock and Stock Option Markets

This study investigates intraday relations between price changes and trading volume of options and stocks for a sample of firms whose options traded on the CBOE during the first quarter of 1986. After purging the price change series of the effects of bid/ask spreads, multivariate time-series analysis is used to estimate the lead/lag relation between the price changes in the option and stock markets. The results indicate that price changes in the stock market lead the option market by as much as fifteen minutes. The analysis of trading volume indicates that the stock market lead may be even longer.     

Price Limits and Stock Market Volatility in the Athens Stock Exchange

In this paper, we have examined the effects of price limits on the stock volatility in the Athens Stock Exchange. We put forward two hypotheses, the information hypothesis, which implies that price limits only slow down the process of adjustment and have no effect on stock volatility; and the over-reaction hypothesis, which assumes that investors tend to overreact to new information, so that price limits give them time to reassess the information and reduce stock volatility. Our results show strong support for the information hypothesis. This evidence is obtained by performing the tests on ten stocks, which include heavily traded stocks as well as less active stocks, and covering a variety of industries, and on a market wide price index. The results are also robust to the frequency of the measurement of the returns, and to the tightness of the limits.     

Imperfect Information and Cross-Autocorrelation among Stock Prices

I develop a model to explain why stock returns are positively cross-autocorrelated. When market makers observe noisy signals about the value of their stocks but cannot instantaneously condition prices on the signals of other stocks, which contain marketwide information, the pricing error of one stock is correlated with the other signals. As market makers adjust prices after observing true values or previous price changes of other stocks, stock returns become positively cross-autocorrelated. If the signal quality differs among stocks, the cross-autocorrelation pattern is asymmetric. I show that both own- and cross-autocorrelations are higher when market movements are larger.     

The Effect of Junk Bond Defaults on Common Stock Returns

This paper examines the effect of junk bond defaults on common stock returns. The evidence indicates that stockholders uncover the signs of financial distress long before the default date. Stock prices fall sharply at the time of the default announcement. Although stocks of fallen angel sample recover slowly and steadily after the default announcement, stocks of the original-issue junk bond sample continue to decline. On average, bankrupt firms suffer larger negative stock returns than defaulted firms not only at the time of announcement, but also in both pre- and post-event periods.     

Information costs and liquidity effects from changes in the FTSE 100 list

Abstract

In this paper we examine the stock price effect of changes in the composition of the FTSE 100 over the time period of 1984–2001. Like the S&P 500 listing studies, we find that the price and trading volume of newly listed firms increases. The evidence is consistent with the information cost/liquidity explanation. This is because investors hold stocks with more available information, implying that they have lower trading costs. This explains the increase in the stock price and trading volume of newly listed stocks to the FTSE 100 List. We find the reverse effect for the deletions from the FTSE 100.     

The Impact of Mispricing and Asymmetric Information on the Price Discount of Private Placements of Common Stock

The price discount on privately placed stock is large and can vary substantially among firms. While earlier studies attribute price discounts on privately placed stock to illiquidity and costs of gathering information, we offer a more complete explanation. We find that firms exhibiting higher overvaluation have significantly larger price discounts in private stock sales. We also find that higher levels of asymmetric information about the issuing firm and about the stock market environment at the time of the private placement cause more pronounced discounts in the offer price. Our analysis also shows that post-issue abnormal returns following private placements are higher when discounts are less pronounced.     

交易限制与股票市场定价效率——基于创业板涨跌幅限制放宽的准自然实验研究

本文基于2020年8月24日创业板涨跌幅限制由10%扩大到20%这一政策变化建立准自然实验,从市场层面与公司事件层面探讨交易限制放宽的外生冲击下市场定价效率的变化。研究发现,涨跌幅限制放宽政策实施后,股票价格能更灵敏地反映公开市场信息,更多地包含公司层面特质信息,整体市场定价效率显著提升。进一步研究表明,涨跌幅限制放宽有效缓解了交易干扰问题,避免了过度交易行为延后,缓解了波动性外溢与价格发现延迟。异质性分析表明,无论是市场层面定价效率改善,还是事件层面波动性外溢、价格发现推迟与交易干扰问题的缓解,均在低信息透明度公司中更为显著。本文研究发现为验证涨跌幅限制会抑制股票市场定价效率的理论提供了直接经验证据,同时为推广完善市场化交易制度提供了有益启示。     

Short-sale constraints and informational efficiency to private information: A natural experiment

Exploiting a regulatory change in short-sale constraints (Regulation SHO) as a natural experiment, this paper examines the effect of short-sale constraints on informational efficiency of stock prices to private information. I find that short-sellers act as informed traders prior to forthcoming analyst news and trade on negative private information. When short-sale constraints are relaxed for pilot stocks (treatment group), both trading volume and stock price sensitivity increase prior to the analyst announcement for bad news but not for good news, relative to that of nonpilot stocks (control group). The findings are consistent with the Diamond and Verrecchia model that predicts that short-selling increases the speed of adjustment of stock prices to private negative information. In the cross-section, the effect of Reg SHO is stronger in stocks of firms with weak and uncertain information environments (i.e., small firms and firms with high analyst forecast dispersion).     

Security Analysts’ Site Visits and Stock Price Synchronicity

This paper investigates how security analysts’ corporate site visits impact listed firms’ stock-price informativeness. Examining a sample of security analysts’ visits to Chinese listed firms from 2010 to 2019, we find that security analysts incorporate firm-specific information into share prices through site visits, significantly reducing the visited firms’ stock price synchronicity. This finding is robust to an alternative measure of stock price informativeness and a two-stage least-squares approach using the introduction of high-speed rail as the instrumental variable. We also find that the impact of analysts’ site visits on firms’ stock price synchronicity is more pronounced for firms with lower information disclosure quality and poor corporate governance than for other firms. Further analysis on firm characteristics documents that this effect is stronger for large-size firms, firms in the manufacturing industry, and state-owned enterprises.     

The Cross-Section of Stock Returns on The Shanghai Stock Exchange

This study explores the cross-sectional stock return behavior on the A-share market of the Shanghai Stock Exchange (SSE), which is segmented from world's other equity markets. We estimate the effects of beta, firm size, book-to-market equity ratio and a variable unique to the Chinese stock markets, the proportion of firm's floating (tradable) equity over total equity on SSE stocks over the period 1993–2002. We find that smaller firms and value stocks perform better. Systematic risk is negatively significant in down markets. The proportion of floating equity has no direct effect on stock returns. JEL Classification: G14, G15     

Common Stock Returns and Rating Changes: A Methodological Comparison

This paper examines the adjustments in a firm's common stock price during the eleven months before and during the month of announcement of a bond rating change. Based on several different measures of abnormal security return, the findings are consistent with the proposition that bond downgradings convey information to common stockholders. For bond upgradings, the price adjustments were statistically insignificant in the month of announcement, although in the eleven preceding months, upgraded firms exhibited positive abnormal returns. While the results do not fully support earlier research, we stress that the main contribution of this article lies in the scrutiny it gives to issues of methodology in assessing the possible price effects of bond reclassifications.     

Sell‐Side Analyst Research and Stock Comovement

We document that a stock's price around a recommendation or forecast covaries with prices of other stocks the issuing analyst covers. The effect of shared analyst coverage on stock price comovement extends beyond analyst activity days. A stock's daily returns covary with the returns of other stocks with which it shares analyst coverage. These links between stock price comovement and shared analyst coverage are consistent with the coverage‐specific information we find in earnings forecasts; analysts who cover both stocks in a pair expect future earnings of the stocks to be more highly correlated than do analysts who cover only one stock from the pair. Collectively, our evidence indicates that analyst research produces coverage‐specific spillovers that raise price comovement among stocks that share analyst coverage. The strength of these spillovers is comparable to spillovers from broad industry and market information in analyst research.     

THE DAY-OF-THE-WEEK ANOMALY: THE TORONTO STOCK EXCHANGE EXPERIENCE

This paper studies the day-of-the-week effect employing Canadian stock returns from January 1, 1975 to June 30, 1989. The study finds that, as opposed to large capitalization stocks, low capitalization (thinly-traded) stocks tend to have a larger negative return on Tuesday rather than on Monday - possibly due to lags in the price adjustment of these stocks following the release of negative information. Two main issues are investigated in an attempt to explain the day-of-the-week effect and its persistence over time: (a) the role of dividends, and (b) the role of information flows. The study finds that firms are much more likely to go ex-dividend on Monday than on any other day of the week; however, after correcting for the dividend effect, Monday's returns are still significantly negative. With respect to information flows, we find evidence consistent with an information-flows-related explanation of the day-of-the-week effect, particularly with the idea that macro announcements cause negative Monday returns.     

Firm Characteristics and Stock Price

This study examines the stock price reaction to the internal control reporting required under Section 404 of the Sarbanes‐Oxley Act of 2002 for three distinct groups of firms. After controlling for general stock price movements, we find that stock returns are most negative for firms that delay filing of their internal control reports, continue to be negative for firms with ineffective internal controls, and are positive for firms with effective internal controls. The decrease in stock prices of the first two groups is more pronounced for those with a lower return on assets, higher growth rate in sales, and no prior disclosure of their internal controls weaknesses. Our results indicate that market participants value the reliability of financial information ensuing from Section 404 compliance, irrespective of firm size and debt proportion. Thus, regulators and policymakers worldwide should consider mandating comparable SOX 404 compliance for all publicly held companies to improve the accuracy and reliability of financial reports.     

The Wealth Effects of Private Stock Placements under Regulation D

This paper examines the wealth effects associated with unregistered private common stock placements under the Regulation D exemption by a sample of exchange listed and over the counter firms. Unlike the negative abnormal returns associated with public equity offerings, private placements of common stocks under Regulation D are initially associated with significantly positive abnormal returns. However, these firms experience significant negative price effects in the two years following the private placements.     

资本市场国际影响力提升效应研究——来自A股纳入明晟(MSCI)新兴市场指数的证据

2018年5月15日,首批纳入明晟(MSCI)新兴市场指数的A股股票名单正式公布。我们发现,被纳入MSCI的股票(标的股票)在公告日前后有显著为正的累计超额收益。相较于主要特征相似的匹配股票,标的股票纳入MSCI后的分析师评级有显著提升。进一步研究表明,在公告日前后融资(融券)交易量显著上升(下降),而换手率没有明显变化,并且净融资交易与公告效应显著正相关。本文的发现表明,A股纳入MSCI这一事件具有明显的信息含量,传递了有关企业前景的正面信息,并促使本地市场聪明投资者进行更活跃的交易,这对促进价格发现、促成价值投资具有一定的推动作用。     

The Costs of Issuing Preferred Stock

U.S. firms commonly use preferred stocks to raise external capital. Yet this hybrid security's issuance costs and offer yields have not been previously examined in a systematic manner. We analyze a sample of 3,042 U.S. preferred stocks issued between 1980 and 1999. We find that convertible issues, which are riskier than straight issues, entail higher gross spreads and other direct expenses. Scale, credit rating, and industry effects influence gross spreads and issuance costs. We also compare preferred stocks yields with various bellwether bond yields. Our results support the tax‐based argument that suggests that yields on preferred stocks should be lower than comparable risky bonds.     

Does Corporate Headquarters Location Matter for Stock Returns?

We document strong comovement in the stock returns of firms headquartered in the same geographic area. Moreover, stocks of companies that change their headquarters location experience a decrease in their comovement with stocks from the old location and an increase in their comovement with stocks from the new location. The local comovement of stock returns is not explained by economic fundamentals and is stronger for smaller firms with more individual investors and in regions with less financially sophisticated residents. We argue that price formation in equity markets has a significant geographic component linked to the trading patterns of local residents.