Was trading EURJPY today via IB IDEALPRO. Entered order to buy 50k at 122.33 when market was 122.38-40. I was immediately filled at 122.2875! Market had not moved, remained at about 122.38-40 for a while longer. Now I don't complain, it was a pleasant surprise. But I wonder how could I get so much price improvement. I have gotten a bit better prices a few times earlier with FX (never with futures or stocks), but never more than one bp. Ten bps in yen is worth $1000 per $1 million lot...
I've had the same thing happen with USDJPY. I'm not sure why it's happened, but of course, nothing to complain about. But two possibilities: 1) Someone entered an order in IDEAL, and because of the wider spreads, entered it below your bid. IB automatically transferred your order to IDEAL to capture it. 2) A market maker transmitted a low offer which IB was able to execute against before you even so it on the screen.
Hurricane, that sounds plausible. Also I guess this would not happen with bigger size (like $1m). If IB quotes were lagging, that would be quite serious. Never seen that happen before in any market, fortunately.
I have not seen lagging forex quotes either. The few times it has happened to me has been with amounts of $50-100k.