So Many Jumps, So Little News

This paper relates jumps in high frequency stock prices to firm-level, industry and macroeconomic news, in the form of machine-readable releases from Thomson Reuters News Analytics. We find that most relevant news, both idiosyncratic and systematic, lead quickly to price jumps, as market efficiency suggests they should. However, in the reverse direction, the vast majority of price jumps do not have identifiable public news that can explain them, in a departure from the ideal of a fair, orderly and efficient market. We show that jumps without news do not correlate with observable proxies for asymmetric or private information, and that microstructure-driven variables have only limited power to help predict the occurrence of jumps without news.