In discussions with traders, there seem to be two camps when it comes to the one tick..."price spikes".....where the price printed is way off the current bid / ask (sometimes it is even outside of the day's current high / low range). One trader I know simply deletes them as and when they occur and says that to not do so screws up his intraday charting indicators and trade signals.....and one other trader swears that they have incredible meaning and that to delete them is a chart destroying move. So....when SPY is trading at 130....and then for one tick it prints 128.75....then goes right back to 130 on the next tick...... ......how do you treat it? CHEERS! D