I've been following some stocks for a while now, examining stock tick data (out of MBTrading). Every now and then there is a trade that happens WAY outside of the bid/ask spread. For example, watching AAPL or GOOG, which tend to have bigger spreads, I occasionally will see a sell at some 30 or 40 cents below the current best bid, or else a buy at something relatively higher than the best offer. These rogue trades do not seem to affect the average on-going price or price direction, at least inasmuch as I've seen. (There are occasionally buys/sells 1 or 2 cents higher or lower than the ask/bid but I have attributed that to the spread being a little behind the trades sometimes - maybe incorrectly?) My question is where these come from? Are they delayed-reported trades from minutes past? More to the point, if these are not delayed reports, how can they get past all the bids and offers on the order book? Thanks in advance! Scott