The Effect Of Concept Stock On Market Pricing Efficiency

The sudden outbreak of COVID-19 in 2020 has seriously affected people’s production and life.The COVID-19 concept stocks derived from this have attracted extensive attention from investors,and the market has shown an irrational exuberant scene of "chasing the rise and killing the fall".As an emerging capital market,China is often known as the "policy market".Investors pay more attention to the underlying stocks of related concept stocks triggered by policies and events,and the phenomenon of concept stock speculation frequently occurs.Therefore,this paper studies the impact of COVID-19 concept stocks on the pricing efficiency of China’s capital market,which is of great significance to the steady and orderly development of China’s capital market.Based on the data of China’s A-share market from January 2011 to December 2020,this paper focuses on stocks related to THE COVID-19 concept and studies the impact of the introduction of COVID-19 concept stocks on the market pricing efficiency based on the propensity score matching method and differential difference model.The research finds that the introduction of COVID-19 concept stocks has brought a certain external impact on the underlying stocks of concept stocks,and has reduced the pricing efficiency of the underlying stocks of COVID-19 concept stocks from two aspects of information response speed and stock price information content.Further research shows that there is a significant negative correlation between the volume of share bar posts and the pricing efficiency,and the increase of share bar posts will reduce the pricing efficiency from two aspects of information response speed and stock price information content.In addition,due to the limitation of investors’ attention,the growth of post volume of different concept stock sectors and the underlying concept stock with different class characteristics is different,which affects the participation degree of noise traders and ultimately leads to the heterogeneity of pricing efficiency.The research of this paper provides a theoretical basis for the capital market to explain pricing efficiency from the perspective of stock market noise information transmission,and has reference significance for the government to timely lock the concept stocks derived from the macroeconomic situation and adjust the allocation of resources.