An intermarket sweep order (ISO) is a limit order that automatically executes in a designated market center even if another market center is publishing a better quotation. An investor submitting an ISO must satisfy order protection rules by concurrently submitting orders to the markets with...

An intermarket sweep order (ISO) is a limit order that automatically executes in a designated market center even if another market center is publishing a better quotation. An investor submitting an ISO must satisfy order-protection rules by concurrently submitting orders to the markets with...

During the Flash Crash on May 6, 2010, a short period of high stock market volatility, some stock prices declined to $0.01, while others increased to $100,000. Examining Intermarket Sweep Orders (ISO) before, on, and after May 6, we find that ISO use is substantially higher on May 6. For those...

An ISO is a limit order designated for automatic execution in a specific market center even when another market center is publishing a better quotation, as long as the trader submits concurrent orders to the other market. We find that ISOs represent 46% of trades and 41% of volume in our sample....