I saw the IB Bulletin that there was a spike in the ES market and they were cancelling trades b/w a certain time period. I <fortunately> didn't have any trades on or pending during this time period, but if i understand an electronic market correctly... why would this spike cause trades to be cancelled. Orders are held on an "electronic book, shouldn't a "spike" just take out these orders on the way up? If they were limit orders they should either be filled at limit price or better, OR the user should be told that the market moved too fast and they're not filled (and therefore still pending). What are the circumstances surrouding the orders getting cancelled (i didn't read the bulletin too closely, but it appears that the official word to cancel trades came about 2 hours after the time frame in question). Is this the case, or did i read the bulletin wrong?