This paper examines the relationship between post–earnings announcement returns and different measures of volume at the earnings date. We find that post-event returns are strictly increasing in the component of volume that is unexplained by prior trading activity. We interpret unexplained volume as an indicator of opinion divergence among investors and conclude that post-event returns are increasing in ex ante opinion divergence. Our evidence is consistent with Varian [1985], who suggests that opinion divergence may be treated as an additional risk factor affecting asset prices.

Using a novel database on venue short sales and market design characteristics, we ask: Where do short sellers exploit their information advantage? Consistent with the prediction of Zhu (2014), we find that exchange short sales comprise a larger proportion of trading and are more informative about future prices than dark-pool short sales, particularly when there is greater competition among short sellers to trade and in the presence of short-lived information. When examining market design characteristics, we find that dark pools offering volume-weighted average price crossing attract more short sales, whereas those offering block trading attract fewer short sales.

Using detailed order handling data, we find that institutional brokers who route more orders to affiliated alternative trading systems (ATSs) are associated with lower execution quality (i.e., lower fill rates and higher implementation shortfall costs). To separate clients’ preference for ATSs from brokers’ routing decisions, we confirm these results for orders where brokers have more order handling discretion, matched broker analysis that accounts for ATS usage, matched child orders that account for client intent, and based on an exogenous constraint on ATS venue choice. Our results suggest that increased transparency of order routing practices will improve execution quality.