We examine the role of high-frequency traders (HFTs) in price discovery and price efficiency. Overall HFTs facilitate price efficiency by trading in the direction of permanent price changes and in the opposite direction of transitory pricing errors, both on average and on the highest volatility...

We examine empirically the role of high-frequency traders (HFTs) in price discovery and price efficiency. Based on our methodology, we find overall that HFTs facilitate price efficiency by trading in the direction of permanent price changes and in the opposite direction of transitory pricing...

We examine the effects of high frequency traders (HFTs) on liquidity using the September 2008 short sale ban. To disentangle the separate impacts of short selling by HFTs and non-HFTs we use an instrumental variables approach exploiting differences in the ban's cross-sectional impact on HFTs and...