Another victory of retail investors: Social media's monitoring role on firms' earnings management

Stock forums are expected to complement individual investors' sophistication via collective wisdom, thus triggering extreme market reactions through uniform scattered opinions. This paper investigates whether stock forums improve corporate governance and decrease earnings management among firms. We found that increased posts, views and comments in a stock forum raise firms' potential costs for obfuscating corporate performance and constrain their upward earnings management. Stock forum discussion tends to increase the likelihood of and the penalties for earnings management detection. By decomposing the cost of earnings management into tangible and regulatory costs, we find that the stock forum governance effect is more pronounced in firms with higher managerial ownership and higher regulatory risk. Social media is a complement and intensifier of traditional mass media. Firms with broader media coverage are more sensitive to the stock forum governance effect. Our results are robust after considering the likelihood that executives will account for stock forum discussion in their reporting decisions.