Influential investors in online stock forums

Internet big data and capital markets: a literature review

“…For existing studies, the stock message boards of Eastmoney.com are the main data sources selected to represent Chinese forums. Examples of such studies include those by Ackert et al (2016), Xiao (2011), Huang et al (2016), Nan (2015), Shen et al (2013) and Zheng et al (2015). Several probable reasons exist for this situation, as follows.…”

“…The former includes the number of posts, clicks, shares, and investors participating in discussions (Ackert et al 2016;Dong and Xiao 2011;Huang et al 2016;Jiang et al 2015;Shen et al 2013;Zheng et al 2015). Simultaneously, most literature has evaluated the information contents of forum posts using textual analysis to construct the content class indicators.…”

“…Studies based on Chinese forums mostly have relied on manual classification with supplementation from simple programming classification (Ackert et al 2016;Nan 2015;Shen et al 2013). In his study on the impact of online public opinions on private placement of listed firms, Shen et al (2013) used web crawler technology to collect all posts that contain the word "additional issue."…”

“…This led to the construction of a variable for the degree of divergence in opinions. Similarly, Ackert et al (2016) manually set up keywords reflecting bullish or bearish market sentiments and then used a program to identify the market sentiments reflected in the posts, thereby building an indicator for trends in market sentiments.…”

“…Their findings demonstrated that the situation in which investors are concerned about home bias is more severe in less developed regions and that the level of concern is affected by market size, turnover rate, and name of securities. Ackert et al (2016) found that the advice of opinion leaders has greater investment value. In addition, the authors were more concerned about corporations from "home" and, thus, were more accurate when making related forecasts.…”