Mobile Trader Informedness and Social Sentiment

Mobile devices offer a communication channel in the financial market. They support mobile trader informedness, the degree to which traders have the information to make decisions about buying and selling stocks. Using market and social media data for three months in 2012 in Korea, we examine how trader informedness from social sentiment affects their buying and selling behavior compared to traders who use the traditional channel without mobile phones. Our design involves econometrics, text analysis, machine learning, and explanatory empiricism to identify causal inferences about how mobile phones affect trader behavior. We show the impacts of social sentiment in the mobile channel have different trading patterns than the traditional channel. Mobile traders make more buys with negative sentiment and sell more with positive sentiment. Traders perceive greater informedness from social sentiment over time, though they may not be more informed. The timing and patterns of their buys and sells are different when daily sentiment is consolidated into a trend over time. They may act on signals leading to patterns of individualistic or contrarian differentiating behavior, opposite to herding behavior. As such, trader informedness plays a critical role due to the diffusion of social sentiment-related financial technology in the past decade.