我国沪市A股涨跌幅限制制度市场效应的实证研究

本文通过分析2001年6月14日-2006年12月31日期间的沪市A股涨跌幅样本数据,综合运用"事件研究法"和"分组比较法"对涨跌幅限制制度的波动性外溢、延迟价格发现和阻碍交易等三个假说进行实证分析,从统计的角度分析我国的涨跌幅限制制度对股市的实际绩效。研究结果显示,涨跌幅限制制度对我国股价的影响具有不对称性,因此并不能就针对某一特定市场的研究,而对涨跌幅限制的市场效应一概而论。     

我国沪市A股涨跌幅限制制度市场效应的实证研究

本文通过分析2001年6月14日-2006年12月31日期间的沪市A股涨跌幅样本数据,综合运用"事件研究法"和"分组比较法"对涨跌幅限制制度的波动性外溢、延迟价格发现和阻碍交易等三个假说进行实证分析,从统计的角度分析我国的涨跌幅限制制度对股市的实际绩效.研究结果显示,涨跌幅限制制度对我国股价的影确具有不对称性,因此并不能就针对某一特定市场的研究,而对涨跌幅限制的市场效应一概而论.     

涨跌幅限制:是否稳定了股票市场?——基于GARCH事件模型的实证检验

本文应用GARCH事件模型对涨跌幅限制政策实施前后市场波动的结构性变化进行了实证检验.研究发现,涨跌幅限制政策对我国股市的波动性具有一定的抑制作用,但是非常有限,同时,涨跌幅对A股市场和B股市场波动性的影响相反.因此,涨跌幅限制并没有如预期的那样发挥比较大的稳定作用,应该适当修正或放宽该政策.     

涨跌幅限制:是否稳定了股票市场?——基于GARCH事件模型的实证检验

本文应用GARCH事件模型对涨跌幅限制政策实施前后市场波动的结构性变化进行了实证检验。研究发现,涨跌幅限制政策对我国股市的波动性具有一定的抑制作用,但是非常有限,同时,涨跌幅对A股市场和B股市场波动性的影响相反。因此,涨跌幅限制并没有如预期的那样发挥比较大的稳定作用,应该适当修正或放宽该政策。     

证券市场价格涨跌幅限制制度的实验研究

采用实验经济学的研究方法在信息对称的实验室股票市场中检验有效市场假说,检验价格涨跌幅限制制度是否能减少股票价格波动和市场的过度投机行为,从而促进市场有效性的提高.实验结果表明,在信息对称的实验室股票市场中,股票交易价格在一定程度上偏离了股票的基本价值,出现了价格偏高或偏低现象,与有效市场假说相悖;并且,价格涨跌幅限制制度不能减少股票价格波动和市场的过度投机行为,反而在很大程度上阻碍了股票交易价格向基本价值靠近的速度,降低了市场有效性,同时也不能降低股票换手率,未能减少市场中投机性交易的数量.证券市场交易制度的政策制定者可以重新评估价格涨跌幅限制制度的作用,进一步深入研究证券市场价格涨跌幅限制制度的合理性.     

夜盘交易与期货市场效率

基于实施夜盘交易前后SHFE的铝期货交易数据,本文运用R/S分析法、共同因子模型等方法从流动性、信息效率及定价效率角度研究夜盘交易制度对期货市场效率的影响。结果发现:夜盘交易的开展,使得铝期货价格的波动性明显下降,市场的流动性显著提升;在夜盘交易后,铝期货价格时间序列的长期记忆性显著下降,历史信息对铝期货价格的影响明显减弱;由于夜盘交易的开展,铝期货市场在长期对现货市场具有显著的引导作用,且在价格发现过程中的贡献也明显扩大。这表明,夜盘交易的开展改善了铝期货市场的流动性、定价效率及信息效率,对期货市场效率的提升具有重要意义。     

涨跌幅限制降低了股价波动吗？——来自中国股票市场的证据

研究发现，涨跌幅限制并没有降低股价波动性和投资的过度反应行为，相反却阻碍了均衡价格的实现过程和投资的正常交易活动，其实际运作绩效与当初预想的目标存在较大偏差。     

套利限制会加剧A-H股定价偏差吗?

本文从资产交易面临的直接约束视角,对套利限制与A-H股定价偏差之间的关系进行分析。以A-H股交叉上市公司为样本,研究发现:(1)套利限制会显著加剧A-H股定价偏差;(2)机构持股比例较高的公司和沪(深)港通开通之后的时间段,套利限制引起的定价偏差边际效应显著降低;(3)相比于制度性限制因子,机构持股和沪(深)港通开通能够更显著降低市场性限制因子对A-H股定价偏差的影响。结果表明,机构投资者的成长、互联互通政策有助于降低市场性限制,从而提高资本市场定价效率,但仍受到内地资本市场既有交易制度设计的约束。     

金融期货价格波动限制机制探讨

金融期货价格稳定机制延缓了价格发现过程，并造成了流动性干扰，但从降低期货、现货交易总成本来讲，它还是利大于弊，因此设置价格波动限制是一种可行的政策，而且在期货、现货市场同时设定的效果最好。此外，从不同价格波动限制方式的影响来看，选择弹性涨跌幅限制可较好地发挥价格限制的好处，减小价格限制的不利影响。     

传统监管措施能够限制金融市场的波动吗？

金融市场传统监管措施的拥护者认为这些措施可抑制过度投机和投资者的过度反应,防止价格剧烈波动,有助于稳定市场。反对者则认为这些措施会阻碍价格发现,降低流动性,反而可能加剧波动。本文分析了中国资本市场的波动性特征,将总体波动率分解为系统波动率和超额波动率。通过追踪监管政策变化的事件,对交易税、杠杆限制、卖空限制、涨跌停板、T+1交易和IPO限制六种监管措施的效果进行了实证检验,发现它们并没有起到抑制波动的作用,并且在大多数情况下降低了市场的流动性。同时也没有证据表明政策的调整是根据波动率的变化而相机抉择的。     

Price limit performance: New evidence from a quasi-natural experiment in China's ChiNext market

This study examines the impact of daily price limits on market performance and trading activity by using a quasi-natural experiment in China. It focuses on the case of the ChiNext market, where the daily price limits of stocks increased from 10% to 20% in 2020. The results show that, initially, the stock prices and occurrences of 10% price limit hits increase, but then decline after the new price limits have been implemented. The level of trading liquidity and volatility increases significantly, with a greater impact on the short term than the long term. These price limit performances are more pronounced for stocks with additional retail interest. The analysis of detailed trading data reveals that institutional investors initially purchase ChiNext stocks in large quantities, followed by retail investors who purchase smaller quantities. In the long run, institutional investors tend to increase their holdings, while retail investors tend to sell their holdings. Additionally, there is a temporary increase in investor attention, price synchronicity, and stock risks, followed by a decline. The findings suggest that wider price limits increase trading volumes and enhance long-term market efficiency, but encourage immediate price manipulation, causing short-term overreactions and long-term reversals. This study provides valuable insights for building an effective price limit system.     

Volume,volatility and information linkages in the stock and option markets

This paper examines the relationship between option trading activity and stock market volatility. Although the option market is uniquely suited for trading on volatility information, there is little analysis on how trading activity in this market is linked to stock price volatility. The bulk of the discussion tends to focus on whether trading activity in the stock market is informative about stock volatility. To analyze the information in option trading activity for stock market volatility, a sample of 15 stocks with the highest option trading volume is selected. For each stock, it is noted that the trading activities in the put and call option markets have significant explanatory power for stock market volatility. In addition, the results indicate that the call option trading activity has a stronger impact on stock volatility compared with that of the put options. Our results demonstrate that information and sentiment in the option market is useful for the estimation of stock market volatility. Also, the significance of the effects of option trading activity on stock price volatility is observed to be comparable to that of stock market trading activity. Furthermore, the persistence and asymmetric effects in the volatility of some stocks tend to disappear once option trading activity is taken into account.     

Effect of the ban on short selling on market prices and volatility

We examine the effects of the short‐selling ban, imposed by Australian regulators in the wake of the global financial crisis, on the trading of financial stocks. Our findings argue against commonly stated reasons for imposing short‐sale bans. We find no evidence that short‐sale restrictions provide support for stock prices or that they reduce volatility. Moreover, stocks subject to the short‐selling ban suffered a severe degradation in market quality. Controlling for the adverse effects of the financial crisis on markets, we show that short‐selling restrictions increase intraday volatility, reduce trading activity and increase bid–ask spreads.     

Option trading after the opening bell and intraday stock return predictability

Prior literature finds that information is reflected in option markets before stock markets, but no study has explored whether option volume soon after market open has predictive power for intraday stock returns. Using novel intraday signed option-to-stock volume data, we find that a composite option trading score (OTS) in the first 30 min of market open predicts stock returns during the rest of the trading day. Such return predictability is greater for smaller stocks, stocks with higher idiosyncratic volatility, and stocks with higher bid–ask spreads relative to their options’ bid–ask spreads. Moreover, OTS is a significantly stronger predictor of intraday stock returns after overnight earnings announcements. The evidence suggests that option trading in the 30 min after the opening bell has predictive power for intraday stock returns.     

Corporate governance and stock performance: The case of COVID-19 crisis

This paper analyzes the impact of COVID-19 on firm-level stock behaviors (including stock price volatility, trading volume and stock returns). Using US data, this paper examines whether confirmed cases (and deaths) of COVID-19 or COVID-19-associated online searches affect stock behaviors. The results show that our five COVID-19 proxies are all positively associated with stock price volatility and trading volume and negatively associated with stock returns. This paper further investigates the mitigating effect of corporate governance (viz., board and ownership structures) in this COVID-19 crisis. Overall, the results suggest that good corporate governance can mitigate the impact of COVID-19 on stock price volatility and trading volume but may not help to enhance stock returns. This paper also considers key policies used to tackle the COVID-19 pandemic and finds that government intervention plays an important role in stabilizing stock markets in this COVID-19 crisis.     

The Media and the Diffusion of Information in Financial Markets: Evidence from Newspaper Strikes

The media are increasingly recognized as key players in financial markets. I investigate their causal impact on trading and price formation by examining national newspaper strikes in several countries. Trading volume falls 12% on strike days. The dispersion of stock returns and their intraday volatility are reduced by 7%, while aggregate returns are unaffected. Moreover, analysis of return predictability indicates that newspapers propagate news from the previous day. These findings demonstrate that the media contribute to the efficiency of the stock market by improving the dissemination of information among investors and its incorporation into stock prices.     

The effect of price limits on intraday volatility and information asymmetry

We investigate the effect of price limits on intra-day volatility and information asymmetry using transactions data from the Taiwan Stock Exchange. Proponents of price limits argue that they provide an opportunity for investors to reevaluate market information and make more rational trading decisions. We identify three different limit hits – closing, single, and consecutive – and hypothesize that only the consecutive limit hits are likely to provide such an opportunity, namely, to counter investor overreaction (volatility hypothesis) and to enhance information revelation (information asymmetry hypothesis). Our empirical evidence supports the volatility hypothesis. Our findings generate important policy implications for stock markets that have price limits.     

Cross-border transmission of stock price volatility: evidence from the overlapping trading hours

Using high-frequency (5-minute returns) data, the transmission pattern of intraday volatility among three international stock markets (i.e., the United States, the United Kingdom, and Canada) during their overlapping trading hours (9:30–11:30 a.m. New York time). The major findings are as follows. First, the conditional variance of a domestic market is affected not only by the volatility surprises of its own market, but also by those of foreign markets. This finding holds for the United States as well as for Canada and the United Kingdom, implying that the information contained in the volatility surprises of each national market is clearly transmitted to other national markets. The volatility spillover is not unidirectional. Second, the magnitude of volatility spillover does not decrease monotonically as the lag length increases, indicating that the effect of a foreign volatility shock on the conditional variance of the domestic market tends to persist.     

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.     

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。