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.

Abstract 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.

ABSTRACT We study intraday market intermediation in an electronic market before and during a period of large and temporary selling pressure. On May 6, 2010, U.S. financial markets experienced a systemic intraday event—the Flash Crash—where a large automated selling program was rapidly executed in the E‐mini S&P 500 stock index futures market. Using audit trail transaction‐level data for the E‐mini on May 6 and the previous three days, we find that the trading pattern of the most active nondesignated intraday intermediaries (classified as High‐Frequency Traders) did not change when prices fell during the Flash Crash.

ABSTRACT After a natural experiment is first used, other researchers often reuse the setting, examining different outcome variables. We use simulations based on real data to illustrate the multiple hypothesis testing problem that arises when researchers reuse natural experiments. We then provide guidance for future inference based on popular empirical settings including difference‐in‐differences, instrumental variables, and regression discontinuity designs. When we apply our guidance to two extensively studied natural experiments, business combination laws and the Regulation SHO pilot, we find that many results that were statistically significant using single hypothesis testing do not survive corrections for multiple hypothesis testing.