Rumors and price efficiency in stock market:An empirical study of rumor verification on investor Interactive platforms

Using rumor verification data from investor interactive platforms,we investigate the effect of stock market rumors on price efficiency.We find favorable rumors are positively correlated with stock price synchronicity,while unfavorable rumors are negatively correlated with stock price synchronicity.Both favorable and unfavorable rumors are positively correlated with stock mispricing levels,and stock price crash risk.Mechanism tests reveal that favorable rumors about industry leaders have industry spillover effects.The effect of rumors on mispricing levels and stock price crash risk are more pronounced when there are more retail investors.Further analysis shows stronger detrimental impacts of rumors on price efficiency for small-cap companies,companies with low information transparency and companies with low institutional ownership.

The capital market spillover effect of product market advertising:Evidence from stock price synchronicity

We analyze whether product market advertising has a spillover effect on stock price synchronicity by transmitting firm-specific information to the capital market and attracting more investor attention.Using a sample of Chinese listed firms from 2009 to 2017,we find that firms with greater advertising expenditures have lower stock price synchronicity.The results are robust after we address endogeneity concerns.In accord with our hypothesis that product market advertising increases the amount of firm-level information capitalized into stock prices through the information channel,we find that the impact of advertising on synchronicity is more pronounced for firms with a higher degree of information asymmetry and firms in the consumer-product industry.Further tests show that product market advertising enhances the ability of current period returns to reflect future earnings,and thus rules out that the negative relationship between advertising and synchronicity is driven by noise trading.Our results imply that product market advertising plays an informative role and improves information efficiency in a capital market.

Does preventive regulation reduce stock price synchronicity?Evidence from Chinese annual report comment letters

Based on a sample of Chinese A-share listed firms from 2015 to 2018,this paper studies the impact of annual report comment letters(ARCLs)on firm stock price synchronicity.We find that after firms receive ARCLs,their stock price synchronicity decreases.Moreover,the longer the ARCLs and the more negative the ARCLs’tone,the lower the resulting stock price synchronicity.The mechanism test shows that after firms receive ARCLs,the firms’information disclosure increases in quantity and quality,external media attention increases,and the firms’governance improves,reducing their stock price synchronicity.Further research shows that this negative association is more significant in firms with higher information asymmetry.This paper shows that the ARCL,an innovative application of the capital market supervision philosophy,is conducive to improving the quality of listed firms and to the healthy development of the capital market.

Harmonious Stock Prices

Stock price movements in China still remain highly harmonious, in spite of the many significant regulatory and structural changes over the recent years. A survey of the literature reveals that harmony in the stock price movements is related to a few salient features in China＇s capital market： high ownership concentration, high incidence of the use of pyramidal ownership structure, significant state ownership, and a lack of active institutional investors. In addition, we also point out that harmonious stock prices may generally result from low intensity of private information acquisitions by risk arbitrageurs.

The Information Efficiency of QFII's Investment in China's Capital Market

This paper takes stock price synchronization and price delay as indicators of information efficiency, and uses mixed cross-sectional data of listed companies into which Qualified Foreign Institutional Investors(QFII) have made investments, to study the impact of QFII's investment behaviors on the information efficiency of China's stock market. The results show that QFII's investments can improve the information efficiency of China's stock market, but its impact is varied. The impact of QFII's investments on market information efficiency is more significant in bear markets than in bull markets, the impact on private enterprises is more significant than on state-owned enterprises, and the impact on Small and Medium Enterprises(SME) market is more significant than in main board market. Further research also finds that QFII has a certain threshold effect on the information efficiency of China's stock market. This research paper provides a problem-solving perspective for China's capital markets to achieve information efficiency through opening up, and at the same time warns against financial risks.

Does Margin Trading Enhance Information Efficiency of the Capital Market?——Evidence from China

On March 31,2010,China formally introduced a margin trading system,which announced that China's capital market has completed the transformation from a unilateral transaction model to a bilateral transaction model with a short-selling mechanism.However,the current development of China's margin trading and securities lending businesses is seriously unbalanced,and the scale of financing far exceeds the scale of securities lending.The short selling effect of securities lending exchanges is extremely limited,which to some extent violates the original intention of introducing the system.In order to help margin trading and securities lending to correct a healthy and sustainable development path,this article uses stock price synchronicity as a proxy indicator to measure the information efficiency of the capital market,explores the impact of the margin trading system on the information efficiency of the capital market,and study the detailed characteristics and economic consequences of the margin trading system.Aiming at this topic,this article analyzes the relationship between margin financing and securities lending and stock price synchronicity.Finally,it analyzes the influence of margin financing and securities lending system on stock price synchronicity from three dimensions of corporate governance,external supervision,and institutional environment mechanism.In terms of empirical research,this article takes advantage of the“quasi-natural experiment”provided by the gradual opening of margin trading and securities lending in China’s securities market,and selects listed companies on the Shanghai and Shenzhen stock exchanges from 2007 to 2019 as the research objects,starting from the perspective of stock price synchronicity,and passing The DID-FE model studies the impact of the margin trading and securities lending system on the information efficiency of the capital market.It uses three methods:parallel trend and dynamic testing,PSM-DID analysis,and placebo testing for robustness testing to solve the endogeneity problem of the experiment.This article also conducts deeper research on the subject based on the two dimensions of the impact mechanism of margin financing and securities lending and the size of the company,and finally discusses the economic impact of margin financing and securities lending on the level of company innovation.

Stock index adjustments and analysts' forecast optimism:A quasi-natural experiment on the CSI 300 Index

As stock index adjustments comprise a basic system of capital market,their potential influence on analysts’earnings forecasts is worthy of research.Based on a research sample of 23 adjustments to the CSI 300 Index from June 2007 to June 2018 and the backup stocks announced during the same period,this study examines the impact of additions to stock index on analysts’forecast optimism using a staggered difference-in-differences model.The research results show that after stocks are added to the stock index,analysts’earnings forecast optimism about these stocks increases significantly.Cross-sectional analysis indicates that this increase is more significant when the market is bullish,institutional ownership is low,the ratio of listed brokerage firms is low,star analyst coverage is low,firms show seasoned equity offering activity,the ratio of analysts from the top five brokerage firms ranked by commission income is high,and the analysts’brokerage firms are shareholders.However,analystlevel tests find that analysts’ability helps to reduce the impact of additions to stock index on earnings forecast optimism.Furthermore,additions to stock index significantly increase analyst coverage and forecast divergence.Economic consequences tests find additions to stock index significantly increases stock price synchronization,which is partly mediated by analysts’earnings forecast optimism.This study enriches the literature on the impact of basic capital market systems and analyst behavior.The findings suggest that investors should rationally evaluate analysts’earnings forecasts for stocks added to the stock index and obtain further information from various channels to improve asset allocation efficiency.

Institutional environment and risk of a stock price crash:evidence from China

Stock price crashes damage China’s macro-financial stability,restrict economic growth,and can lead to huge losses in wealth for investors.Therefore,how to reduce the risk for stock price crashes is an important theoretical and practical issue.This paper mainly studies the effects of the institutional environment that creates risks for stock price crashes.Using China’s non-financial A-share listed companies from 1997 to 2012 as an example,this paper finds that the lower the level of government intervention is,the better the legal environment is,the faster the market process in business area is,then the lower the risks for stock price crashes will be.To solve the endogenous problem between the institutional environment and the risk of a stock price crash,this paper uses the number of seaports and whether the commercial ports or leased territories are opened after the first Opium War in Qing Dynasty as instrumental variables of the institutional environment.We find that the above conclusion is still valid with the method of 2SLS regression.Furthermore,this paper also finds that the government intervention index,the legal environment index,and the market index are negatively related to stock price synchronicity to a significant degree.These conclusions illustrate that the institutional environment is an important factor in the healthy and stable development of the capital market,which has important implications for policy markers or regulators to develop policies to promote the stable development of the stock market,to control market risk of listed companies,and to make investment decisions.