I have been working with the IB demo account and API to develop a somewhat complex FX arb application. While working with the demo data, I see no arb opportunity most of the time, but maybe 2-3 times per day, I see moderate to large trading opportunities. With the demo account, I can drop in market orders, and watch them get filled rapidly, earning a nice paper profit. I opened a real account and funded it earlier this week, but the real data appears to be nothing like the demo data. I understand that the data is supposed to be 15 minutes delayed, but I never see the moderate or large arb opportunities show in the IB data. This makes me wonder: where does IB get their FX data? I see the following possibilities: (1) The data is completely fabricated and doesn't really represent any real FX trades, delayed by 15 minutes or not. This seems unlikely, because the demo data looks very reasonable. It seems to correlate with real world events. But when looked at closely, it just isn't the same as live data. It seems unlikely that IB would go to the effort to fabricate data anyway - adding a delay onto real data is far simpler than trying to build an RNG that produces realistic currency data. I don't think they have Benoit Mandelbrot hiding in their back office. (2) The data is real live data, but it is the data before IB gets a chance to trade it themselves. IB claims on their website that they are among the largest program traders on the NYSE. Given their history of trading since the '70s, their analysts should have come up with every possible arbitrage opportunity in every market. The result would be an "ideal" arbitrage-free efficient market for their customers, who would be left to only make directional trades in FX (and elsewhere). (3) the data comes from some other quote vendor that has access to different FX trading parties. This is actually distinct from case (2). When I was looking for evidence of case (2), I ran the demo account and my trading system in parallel with my real account and trading system. I expected that when the demo trading system was earning me Gulfstreams and Veyrons, the live trading system would show much smaller "bumps" fifteen minutes ahead of the demo system. I saw no such bumps. In the few cases where there was profit in the live system, it was never followed by (delayed) corresponding bumps in the demo system. so: Can anyone provide any insight into where IB might be getting their data? If it is real, live data, I would love to be able to trade there. How would I find FX firms that allow the kind of trading complexity that IB does, with better market access?