Some traders say one culprit for the quick downdraft might have been a type of trade called an "intermarket sweep order," or ISO. ISOs, which some studies say account for nearly half of all trades, send trades to whatever exchange that has the best price. The order can remain there until it is filledâeven if that means the price falls to near zero. A large number of stocks that plunged dramatically Thursday were ISO orders in which there were no apparent buyers, data shows. Shares of consulting firm Accenture PLC fell from $41 at 2:30 p.m. to $32.62 at 2:47:46 when a trade was routed through NYSE Arca Exchange. Seconds later, at 2:47:50 p.m. an ISO trade cleared through Nasdaq at $5.54. Moments later, an ISO trade went through on Nasdaq at $3.04. The shares traded at a penny at 2:47:53 p.m.... http://online.wsj.com/article/SB100...7716.html?mod=WSJ_hpp_LEFTWhatsNewsCollection What a joke. And you are calling the US electronic markets "sophisticated" ???? That's Third World quality.