A price dynamic equilibrium model with trading volume weights based on a price-volume probability wave differential equation

Guided by a price-volume probability wave differential equation in a new mathematical method, we study intraday market dynamic equilibrium in stock market. We select intraday cumulative trading volume distribution over a price range as individual mental representation and determine a price equilibrium point by the maximum volume utility price. We propose the hypothesis that a stock price can deviate away from the equilibrium point in momentum and restore to it in reversal, and the volume distribution embodies market dynamic equilibrium. Then, we examine it by a set of explicit price dynamic equilibrium models with trading volume weights from the differential equation against a large number of the price-volume distribution using tick-by-tick high frequency data in Chinese stock market in 2019. It holds true. We can infer that the theory is applied for a broader scope because it embraces core mathematical components in expected utility theory, prospect theory, and reflexivity theory.     

基于面板数据的我国知情交易与股价信息含量研究

知情交易概率是指知情交易委托单占总交易委托单的比重,用于度量我国知情交易强度。R2代表公司回报率能被市场回报率解释的程度,R2越大,股价信息含量越低。在以往的研究基础上,利用面板数据来考察知情交易概率与股价信息含量的关系,发现知情交易概率越低,R2越高,股价信息含量越低。在控制了流动性与部分公司财务指标后,实证结果依然显示我国股价信息含量与知情交易概率存在正相关关系,说明我国知情交易者进行交易时,更有利于公司特质信息进入股票价格。     

With or without you: market quality of floor trading when screen trading closes early

Most stock markets are characterized by a number of parallel operating trading systems which interact intensively with each other. Usually, smaller trading platforms take the leading domestic main market as a benchmark in the price discovery process and for closing open trading positions. But what happens if the smaller trading systems suddenly have to act without this benchmark platform? We examine the effects of the reduction of the daily business hours of a screen based main trading system while a parallel floor based trading system keeps on operating. We provide evidence that liquidity improves while informed trading and informational efficiency of prices decrease at the floor based trading system as a result of the no longer operating main market. While prior research on parallel trading focuses on changes due to a growing number of trading venues, we present the first evidence on market effects when the main trading platform reduces trading hours.     

股指期货市场操纵与价格发现功能的关系研究

股指期货市场操纵会影响股指期货市场的价格发现功能,同样地,股指期货市场的价格发现功能也会影响股指期货市场的操纵行为。本文在理论探讨的基础上,利用股指期货主力合约及对应的沪深300指数高频数据对市场操纵行为进行实证分析。研究结果表明,当操纵嫌疑只存在于期货市场时,股指期货市场的价格发现功能将会减弱;当操纵嫌疑存在于期货、现货两个市场时,股指期货市场的价格发现功能相对会增强。而且,当股指期货市场价格发现功能较强时,市场操纵的难度和成本都将下降。当前中国股指期货市场的操纵行为可能主要局限于某些个别的、离散的交易日内,系统地通过操纵现货指数来操纵期货市场的可能性较低。     

Informed traders and their market preference: Empirical evidence from prices and volumes of options and stock

The causal structure of price and volume in options and stock markets is examined to investigate whether a preferred market for informed trading exists. The possible trade-off of leverage on one hand and liquidity and transactions costs on the other, and the effect of different market mechanisms, are discussed in this context.We test for cointegration and use the vector error correction (VEC) approach if we find it. Otherwise, causality tests are via the conventional vector autoregression (VAR). We find that volume leads price in both markets, but that option volume leads stock volume, and stock price leads option price. These results differ from previous studies. Potential explanations are discussed.     

Derivatives traders’ reaction to mispricing in the underlying equity

This article examines trading behavior in the options market conditioned on mispricing in the underlying stock. We investigate the price equilibrium between the observed equity asset and the options-implied synthetic share as well as the relative divergence between the two prices. We find a consistently positive relation between the level of stock mispricing and violations of the upper-boundary condition using derivatives, along with an increase in price divergence. To control for the effect of shorting limitations on mispricing, we further examine prices during the short-sale ban in 2008. The results hold and in many instances are more significant during the ban period. Given the persistent disequilibria between the synthetic and observed stock prices, we argue the results are evidence of informed trading in the derivatives market.     

Heterogeneously informed trading and the stock market efficiency during the COVID-19 pandemic

This study investigates the U.S. stock market efficiency from the symmetric and asymmetric perspectives during the COVID-19 pandemic. We explore that the pandemic boosts (hurts) the information role of symmetrically (asymmetrically) informed trading. Specifically, we find that the epidemic outbreak and infection scale strengthen (weaken) the stock return reaction to symmetrically (asymmetrically) informed trading. Evidence also indicates that the effect of symmetrically (asymmetrically) informed trading on stocks' permanent price shocks and price informational efficiency is enhanced (impaired) during the pandemic. Moreover, all these effects are consistently more intensive to informed buys.     

Dynamic price discovery

This article analyzes the dynamic process of price discovery in a competitive securities market where investors are equally informed about the fundamental determinants of an asset's end-of-period value but, because they do not know each other's wealth positions, do not know the equilibrium price of shares at the start of a current trading session. Because a large number of participants is assumed, issues concerning market impact and market manipulation are avoided. As trading progresses, participants update their expectations of an asset's equilibrium value. As they do so, price can either converge to a new level or, following a run, revert back to a previous level. This implies that, in clusters of adjacent prices, price changes are more apt to be predominantly of like sign (positive or negative) than would be the case under random walk with a bid-ask spread. Moreover, reversals, when they do occur, should be larger than continuations. An examination of 1988 transactions data for the 30 Dow Jones Industrial stocks shows that this is indeed the case. With the effect of the bid-ask spread removed, first-order autocorrelation coefficients are found to be positive.     

Why Do Price Limits Exist in Stock Markets? A Manipulation‐Based Explanation

Numerous stock market regulators around the world impose daily price limits on individual stock price movements. We derive a simple model that shows that price limits may deter stock market manipulators. Based on our model's implications, we predict that regulators impose price limit rules for markets where the likelihood of manipulation is high. We present empirical evidence consistent with this hypothesis. Our study is the first to formally propose a manipulation‐based rationale for the existence of price limits in stock markets.     

Stock market dynamics with rational liquidity traders

In the Kyle (1985) finite horizon model of stock market dynamics with a trader who holds long-lived information, informed trading intensities rise with time, and the slopes of the equilibrium price schedules fall. This paper shows that this result depends crucially on the irrational liquidity trader assumption. We replace the irrational noise traders with a sequence of rational, risk averse, liquidity traders who receive endowment shocks to their holdings of the risky asset. We demonstrate that unless liquidity traders are sufficiently risk averse, the slope of equilibrium price schedule rises over time, while informed trading intensities fall. In particular, Kyle's result holds only when liquidity traders are so risk averse that they ‘over-rebalance’ their portfolio's holdings of the risky asset, so that their final holdings of the risky asset have the opposite sign of their initial position.     

Which trades move prices in emerging markets?: Evidence from China's stock market

This paper extends Barclay and Warner's [Barclay, M.J. and J.B. Warner (1993), ‘Stealth trading and volatility: which trades move prices?’, Journal of Financial Economics, vol. 34, pp. 281–306.] original work on stealth trading by analysing which trades move price for the emerging Chinese stock market. A large block trade/manipulation hypothesis is proposed in addition to the stealth and public information hypotheses examined by Barclay and Warner. Using high-frequency data the results show that while medium and large-size trades are associated with disproportionately large, overall, cumulative stock price changes, it is the large-size trades (in terms of the number of transactions) which have the largest effect on cumulative price increases. Thus, while there is some support for stealth trading in the Chinese market, there are other effects in operation such as large block trades/price manipulation.     

并购重组前的知情交易行为研究

并购重组中基于内幕信息的知情交易行为既是监管重点,也是学术界关注的热点问题。本文以2006—2020年我国上市公司并购重组事件为样本,考察并购重组前的知情交易行为对并购公告收益的影响。研究发现：并购重组前的知情交易行为引发了主并公司股价的提前反应,从而降低了并购公告时的市场反应,这一现象是由内幕信息泄露引起,且内幕信息主要来源于包括员工在内的公司内部人,而非机构投资者。进一步分析表明,改善信息环境可以有效缓解并购重组的信息泄露问题,体现为知情购买交易的信息泄露效应受到分析师跟踪、审计质量和问询函制度的有效制约。本文研究深化了现有的并购重组内幕交易行为研究,为实施精准监管和防范内幕交易等政策提供了一定参考和依据。     

Short sales constraint and SEO pricing

We examine the influence of SEC's Rule 105 on informed trading and the information content of stock prices around an SEO's offer day. We show that constraints on short sales inhibit informed trading and hamper incorporation of information into stock prices for offers whose traders have private adverse information and without options listing. The constraints contribute to increased price uncertainty and higher market sensitivity to seller-initiated trading. After controlling for other causes of SEO discounts, we find that the decrease in information content of stock prices just before an offer day has a significant impact on the SEO's value discount.     

An Empirical Analysis of Illegal Insider Trading

Whether insider trading affects stock prices is central to both the current debate over whether insider trading is harmful or pervasive, and to the broader public policy issue of how best to regulate securities markets. Using previously unexplored data on illegal insider trading from the Securities and Exchange Commission, this paper finds that the stock market detects the possibility of informed trading and impounds this information into the stock price. Specifically, the abnormal return on an insider trading day averages 3%, and almost half of the pre-announcement stock price run-up observed before takeovers occurs on insider trading days. Both the amount traded by the insider and additional trade-specific characteristics lead to the market's recognition of the informed trading.     

Business strategy,stock price informativeness,and analyst coverage efficiency

We examine how business strategy affects stock price informativeness which in turn influences analyst coverage efficiency. Using stock price synchronicity and the probability of informed trading as proxies for stock price informativeness, we show that stock prices of prospectors are less informative than those of defenders. Next, we explore two channels through which business strategy influences analyst coverage efficiency. We first test and find support for an information transfer channel, i.e., the higher stock price synchronicity of prospectors facilitates more information transfer by analysts, resulting in higher analyst coverage efficiency of prospectors than defenders. Next, we test and find support for an informed trading channel, i.e., the higher probability of informed trading on stocks of defenders intensifies competition between informed traders and analysts. Such competition adversely affects analyst coverage efficiency, leading to lower analyst coverage efficiency of defenders than prospectors. Our findings are robust to an array of robustness checks including 2SLS/IV tests, differences‐in‐difference tests, and high‐tech industry sensitivity analyses.     

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.     

Information-based stock trading and managerial incentives: evidence from China's stock market

This paper uses stock price informativeness, or information-based stock trading, to help explain the pay–performance sensitivity (PPS) of chief executive officer (CEO) compensation in China's listed firms. We argue that higher stock price informativeness, which we measure by the probability of informed trading, helps and encourages shareholders to incentivize the top management team based on stock market performance. The regression results support our argument and show that a higher level of stock price informativeness is associated with higher CEO PPSs. Moreover, the impact of stock price informativeness on CEO incentives is stronger for privately controlled listed firms than it is for state-controlled listed firms. The results also hold when information asymmetry is approximated by the accuracy and dispersion of the earnings forecasts made by financial analysts.     

Price discovery in the U.S. stock and stock options markets: A portfolio approach

Option prices vary with not only the underlying asset price, but also volatilities and higher moments. In this paper, we use a portfolio of options to seclude the value change of the portfolio from the impact of volatility and higher moments. We apply this portfolio approach to the price discovery analysis in the U.S. stock and stock options markets. We find that the price discovery on the directional movement of the stock price mainly occurs in the stock market, more so now than before as an increasing proportion of options market makers adopt automated quoting algorithms. Nevertheless, the options market becomes more informative during periods of significant options trading activities. The informativeness of the options quotes increases further when the options trading activity generates net sell or buy pressure on the underlying stock price, even more so when the pressure is consistent with deviations between the stock and the options market quotes. JEL Classification C52, G10, G13, G14     

A network perspective of the stock market

Complex networks are constructed to study correlations between the closing prices for all US stocks that were traded over two periods of time (from July 2005 to August 2007; and from June 2007 to May 2009). The nodes are the stocks, and the connections are determined by cross correlations of the variations of the stock prices, price returns and trading volumes within a chosen period of time. Specifically, a winner-take-all approach is used to determine if two nodes are connected by an edge. So far, no previous work has attempted to construct a full network of US stock prices that gives full information about their interdependence. We report that all networks based on connecting stocks of highly correlated stock prices, price returns and trading volumes, display a scalefree degree distribution. The results from this work clearly suggest that the variation of stock prices are strongly influenced by a relatively small number of stocks. We propose a new approach for selecting stocks for inclusion in a stock index and compare it with existing indexes. From the composition of the highly connected stocks, it can be concluded that the market is heavily dominated by stocks in the financial sector.     

Market manipulation: A comprehensive study of stock pools

Using a new hand collected data set, this paper examines in detail a classic account of stock market manipulation, the “stock pools” of the 1920s, which prompted the current antimanipulation rules in the United States. We examine abnormal turnover and returns and the relation between them, as well as the long-term performance of the selected stocks. We conclude that the evidence suggests informed trading rather than manipulation. Our findings have implications for regulatory policy as well as the investigation and prosecution of manipulation cases.