Market reaction to internet news: Information diffusion and price pressure

A number of researchers have documented the market response to various recommendations from the mass media over different periods and summarised two main hypotheses for the underlying mechanisms: price pressure hypothesis (PPH) and information diffusion hypothesis (IDH). However, few studies have investigated the underlying mechanisms of the market reaction to Internet news. This paper uncovers the underlying mechanisms by examining the market reaction to Internet news mentioned in the daily “Investment Focus” and “Announcement Interpretation” in the column of “Ahead of Stock Market”. The empirical results show a significantly positive abnormal return and excessive trading volume on the event date. The cumulative abnormal return of “Announcement Interpretation” completely reverses within 50 trading days, which supports the PPH. The cumulative abnormal return of “Investment Focus” partially reverses within 50 trading days, which supports the IDH. By partitioning each sample into high information and low information subgroups, the empirical results further suggest that the PPH and IDH are not mutually exclusive. Taken together, the results provide some explanations for the market reaction to Internet news.