Do Short Sellers Trade on Private Information or False Information?

We investigate whether short sellers contribute toward the informational efficiency of market prices by trading on their private information or destabilize market prices by trading on rumors and false information. We find that short-selling activities are considerably informative about future stock returns when there is a higher likelihood of private information in stocks, as measured by insider-trading activities. Short sellers also bring considerable additional information to the market that is not fully captured by contemporaneous insider trading. Overall, these results suggest that on average, short sellers bring informational efficiency to market prices rather than destabilize them.