交易所大宗交易流动性折价研究——来自沪深交易所的经验证据

随着证券市场规模的扩大及机构投资者规模的壮大，机构投资者对市场流动性的需求日益剧增，大宗交易制度是满足投资者流动性需求的制度性创新。由于大宗交易的数量较大，其交易价格有别于正常交易规模的价格。本文利用沪深交易所的大宗交易数据实证探讨大宗交易价格及其影响因素。研究结果表明，大部分大宗交易价格低于当日收盘价格，呈现流动性折价现象，折价率达到1．27％：研究还发现，折价水平还受交易数量、正常交易时间段股票流动性水平、市场流动性水平及股价波幅等因素影响。     

Do institutional investors destabilize stock prices? evidence from an emerging market

In this paper, we provide empirical evidence on the impact of institutional investors on stock market returns dynamics in Poland. The Polish pension system reform in 1999 and the associated increase in institutional ownership due to the investment activities of pension funds are used as a unique institutional characteristic. We find robust empirical evidence that the increase of institutional ownership has changed the autocorrelation and volatility structure of aggregate stock returns. However, the findings do not support the hypothesis that institutional investors have destabilized stock prices. The results are interpretable in favor of a stabilizing effect on index stock returns induced by institutional trading.     

Gone fishin’: Seasonality in trading activity and asset prices

We use seasonality in stock trading activity associated with summer vacation as a source of exogenous variation to study the relationship between trading volume and expected return. Using data from 51 stock markets, we first confirm a widely held belief that stock turnover is significantly lower during the summer because market participants are on vacation. Interestingly, we find that mean stock return is also lower during the summer for countries with significant declines in trading activity. This relationship is not due to time-varying volatility. Moreover, both large and small investors trade less and the price of trading (bid-ask spread) is higher during the summer. These findings suggest that heterogeneous agent models are essential for a complete understanding of asset prices.     

Individual Investors and Volatility

We show that retail trading activity has a positive effect on the volatility of stock returns, which suggests that retail investors behave as noise traders. To identify this effect, we use a reform of the French stock market that raises the relative cost of speculative trading for retail investors. The daily return volatility of the stocks affected by the reform falls by 20 basis points (a quarter of the sample standard deviation of the return volatility) relative to other stocks. For affected stocks, we also find a significant decrease in the magnitude of return reversals and the price impact of trades.     

Speculative dynamics and price behavior in the Shanghai Stock Exchange

This article examines the extent to which the trading behavior of heterogeneous investors manifests in stock price changes of asset portfolios which constitute the Shanghai Stock Exchange. There are three major findings that materialize. Firstly, reliable statistical evidence of a negative relation between the conditional first and second moments of the return distributions of stock prices lends support to the volatility feedback effect. Secondly, ‘feedback’, or momentum-type investors, are not present in this market as is often detected from the daily price changes of other industrialized markets. Finally, trade volume as a proxy for ‘information-driven’ trading suggests that such investors play a statistically significant role in stock price movements. Parameter estimates from this latter group of investors imply that a rise in stock prices from a high volume trading day is more likely than a rise resulting from a low volume trading day.     

Excess Volatility and UK Investment Trusts

Abstract:   The issue of whether or not asset prices are more volatile than the underlying fundamentals is an empirical question with implications for market efficiency. Recent research suggests that the volatility of closed end fund returns in the USA is significantly higher than the returns on assets held by the funds. This has been attributed to noise trading as closed‐end fund shares are predominantly held by individual investors. This study demonstrates that UK investment trust returns exhibit similar excess volatility in spite of the prevalence of institutional investors. However, big investment trusts in terms of market capitalisation show greater excess volatility than small trusts. Although most of the excess volatility appears to be idiosyncratic, investor sentiment index is the most important variable associated with residual returns.     

DO INVESTORS CARE ABOUT PRESIDENTIAL COMPANY‐SPECIFIC TWEETS?

When the president of the United States tweets, do investors respond? We analyze the impact of tweets from President Donald J. Trump's official Twitter accounts from November 9, 2016 to December 31, 2017 that include names of publicly traded companies. We find that these tweets move company stock prices and increase trading volume, volatility, and institutional investor attention, with a stronger impact before the presidential inauguration. There is some evidence that the initial impact of the presidential tweets on stock prices is reversed in the next few trading days.     

Chasing trends: recursive moving average trading rules and internet stocks

The recent rise and fall of Internet stock prices has led to popular impressions of a speculative bubble in the Internet sector. We investigate whether investors could have exploited the momentum in Internet stocks using simple moving average (MA) trading rules. We simulate real time technical trading using a recursive trading strategy applied to over 800 moving average rules. Statistical inference takes into account conditional heteroscedasticity and joint dependencies. No evidence of significant trading profits is found. Most Internet stocks behave as random walks; this, combined with high volatility, may be the reason for the dismal performance of the moving average rules.     

基于小波CCC-GARCH模型的融资融券交易与证券市场波动率关系研究

以2010年4月2日～2016年7月21日的中国证券市场交易数据为样本,运用小波CCC-GARCH模型,考量融资融券交易对证券市场波动率的影响.结果表明,融资交易行为对证券市场收益率和成交量的波动均有较显著的影响,而融券交易对市场波动率的影响不显著.同时,融资交易行为对市场的影响主要由高频信号所驱动,投资者短期非理性行为或噪音交易对市场波动的影响较大.为促进市场的健康发展,应均衡融资融券业务的发展,培养理性机构投资者,加强投资者风险警示加快融资融券数据库的建设.     

Daily institutional trades and stock price volatility in a retail investor dominated emerging market

We examine the short-run dynamic relation between daily institutional trading and stock price volatility in a retail investor-dominated emerging market. We find a significantly negative relation between volatility and institutional net trading that is mainly due to the unexpected institutional trading. The price volatility–institutional trade relation differs for institutional buys and institutional sells, and for small and large stocks. Institutional investors herd-trade in large stocks, but do not systematically engage in positive-feedback trading. We argue that the net impact of informational and noninformational institutional trades determines the relation between volatility and institutional trading, and that the relation is negative when informational trading by institutions prevails.     

投资者关注与市场反应——来自中国证券交易所交易公开信息的自然实验

涨停的股票能否被交易公开信息披露取决于收益率排名中的随机因素,与股票的基本面特征无关。本文利用这一机制设计自然实验检验了投资者关注对股价的影响。实证结果显示交易公开信息披露使股票受到投资者更多的关注,增加了小额资金的净流入,减少了大额资金的净流入和股价的短期收益率,抑制了股价短期波动率,同时降低了股价在长期发生反转的可能性。频繁登上交易公开信息的知名营业部买入的股票受到更多关注,相应的市场反应也更加显著。进一步的研究表明监管性信息披露引发的投资者关注通过降低市场信息不对称抑制了股价反转。     

Investor Sentiment,Trading Behavior and Informational Efficiency in Index Futures Markets

This paper shows that traders in index futures markets are positive feedback traders—they buy when prices increase and sell when prices decline. Positive feedback trading appears to be more active in periods of high investor sentiment. This finding is consistent with the notion that feedback trading is driven by expectations of noise traders. Consistent with the noise trading hypothesis, order flow in index futures markets is less informative when investors are optimistic. Transitory volatility measured at high frequencies also appears to decline in periods of bullish sentiment, suggesting that sentiment‐driven trading increases market liquidity.     

VOLATILITY FORECASTS,TRADING VOLUME,AND THE ARCH VERSUS OPTION‐IMPLIED VOLATILITY TRADE‐OFF

We investigate empirically the role of trading volume (1) in predicting the relative informativeness of volatility forecasts produced by autoregressive conditional heteroskedasticity (ARCH) models versus the volatility forecasts derived from option prices, and (2) in improving volatility forecasts produced by ARCH and option models and combinations of models. Daily and monthly data are explored. We find that if trading volume was low during period t?1 relative to the recent past, ARCH is at least as important as options for forecasting future stock market volatility. Conversely, if volume was high during period t?1 relative to the recent past, option‐implied volatility is much more important than ARCH for forecasting future volatility. Considering relative trading volume as a proxy for changes in the set of information available to investors, our findings reveal an important switching role for trading volume between a volatility forecast that reflects relatively stale information (the historical ARCH estimate) and the option‐implied forward‐looking estimate.     

Insider trading,stock return volatility,and the option market's pricing of the information content of insider trading

We find strong evidence that net insider selling is positively associated with future stock return volatility, consistent with insider selling increasing outside investors’ uncertainty. The positive effect of net insider selling is significantly stronger when the volatility is measured around the earnings announcement. Apparently, option prices do not fully reflect the information content of insider trading for future volatility. More specifically, we find no evidence that option traders adjust the implied volatility for the insider trading effect in a timely manner. Consequently, net insider selling is significantly associated with future option straddle returns and delta neutral returns.     

限制交易政策如何影响期现关系?——对股指期货价格发现功能的实证检验

本文利用2015年中国股市大幅下跌期间,对股指期货严格限制交易政策这一独特事件前后的高频数据,研究限制交易政策对股指期货与股票市场价格引导关系的影响。利用I-S模型和分位数回归方法的实证结果表明:限制交易政策实施前,股指期货对股票市场的价格影响更强,尤其表现在价格急剧下跌时期;限制交易政策显著增加了期货市场交易成本,从而降低了期货市场的信息份额,削弱了其对股票市场的价格影响,并且改变了期货价格对现货价格“助跌强于助涨”的影响模式,增强了股指期货在价格上涨时对股票市场的影响。研究结果一方面直接量化了期货交易成本变动对其价格发现功能的负面影响,另一方面也从价格引导关系的视角提供了股市危机时期股指期货限制交易政策监管效果的实证证据。     

Institutional trading,information production,and corporate spin-offs

We use a large sample of transaction-level institutional trading data to analyze, for the first time in the literature, the role of institutional investors as producers of information around corporate spin-offs. Our results may be summarized as follows. First, there is a significant imbalance in post-spin-off institutional trading between the equity of new parent firms versus subsidiaries, suggesting that spin-offs increase institutional investors' welfare by relaxing a trading constraint. This imbalance in institutional trading is driven by differences in information asymmetry across the two spun-off firm divisions. Second, institutional trading around spin-offs has significant predictive power for the announcement effect of a spin-off and for post-spin-off long-run stock returns. Third, institutional investors are able to realize significant abnormal profits by trading in the subsidiary firm equity in the first quarter post-spin-off. Overall, we show that spin-offs enhance information production by institutional investors, who profit from this enhanced information production.     

Informed Trading in Stock and Option Markets

We investigate the contribution of option markets to price discovery, using a modification of Hasbrouck's (1995) "information share" approach. Based on five years of stock and options data for 60 firms, we estimate the option market's contribution to price discovery to be about 17% on average. Option market price discovery is related to trading volume and spreads in both markets, and stock volatility. Price discovery across option strike prices is related to leverage, trading volume, and spreads. Our results are consistent with theoretical arguments that informed investors trade in both stock and option markets, suggesting an important informational role for options.     

Large Investors, Price Manipulation, and Limits to Arbitrage: An Anatomy of Market Corners

Corners were prevalent in the nineteenth and early twentieth century. We first develop a rational expectations model of corners and show that they can arise as the result of rational behavior. Then, using a novel hand-collected data set, we investigate price and trading behavior around several well-known stock market and commodity corners which occurred between 1863 and 1980. We find strong evidence that large investors and corporate insiders possess market power that allows them to manipulate prices. Manipulation leading to a market corner tends to increase market volatility and has an adverse price impact on other assets. We also find that the presence of large investors makes it risky for would-be short sellers to trade against the mispricing. Therefore, regulators and exchanges need to be concerned about ensuring that corners do not take place since they are accompanied by severe price distortions.     

The Intraday Relation between NYSE and CBOE Prices

I extend the literature regarding price discovery across stock and option markets through an empirical model that allows information to flow through an error‐correction term and volatility. NYSE prices tend to lead CBOE prices by at least thirty minutes over the entire six‐year sample period. In addition, informed trading in the options market is revealed more strongly through persistence in volatility and the spillover of volatility to the stock market than it is through returns.     

Risk sharing in a financial market with endogenous option prices

This article investigates a financial market in which investors may trade in risk-free bonds, stock and put options written on the stock. In each period, stock and option prices are simultaneously determined by market clearing. While the introduction of put options will decrease the systematic risk in the financial market, it will increase the price of risk. Investors with mean-variance preferences will generally hold portfolios containing the primary asset and the put option and may use the option to increase the risk in their wealth position in exchange for higher returns. Aggregate wealth is unaffected by an option market when there are no spillover effects on stock prices, and it is shown that short selling of options will increase the volatility of individual wealth positions. Investors with erroneous beliefs may on average be better off not trading in put options.