This is a specific question as to what party would liable for a failure to enact a stop order. Here are two links that partly address this subject. I see that Don Bright is the author of the first one....perhaps he might instantly know the answers here. http://www.traders.com/index.php/sa...cts-of-trading/805-stop-orders-a-conversation http://www.trade2win.com/boards/direct-access/81922-sec-requirements-stop-orders.html As we know, some exchanges accept stop orders and some do not. For example, ARCA no longer does. Yet NASDAQ does accept them. For variety of reasons not pertaining the question, I prefer using these exchanges. When using any route, the stop order wherewithal is available, either through the platform vendor you happen to be using (such as DAS or Sterling) or by some other 3rd party mechanism, or by your broker (as with IB in the above example). However, with most if not all of these 3rd party stop systems, they understandably have disclaimers that basically state that if there is the unlikely glitch, or server failure,or anything of the sort, then the 3rd party vendor holding these stops are not liable for the failure of executing these stop orders. This is an unlikely occurrence, yet possible. The succinct questions are these.... 1) Since, for example, the NASDAQ OMX does accept stop orders as an exchange,...if one were to route a stop order to NASDAQ OMX to where that stop sits in their exchange servers, would the liability for the execution of that stop order lie with that exchange?...as opposed to the trader? Implicitly is there any advantage to this? 2) If the answer to 1) is 'yes', should not this be something that traders who use stop orders be aware of? Or is the risk of failure and worse case scenario so low that it is relatively inconsequential despite the vendor disclaimers? I have scoured the SEC regs and the NASDAQ website to assess this, but cannot find it in any disclaimers or regulations. I have consulted with numerous owners and risk managers of prop firms, and I cannot get an absolute answer to this. It would appear to me that it is 'answerable'. Thanking you in advance for any answers here.