Has anyone done any correlation studies to see how closely LMAX tracks other markets, in general and around big moves? For example, FX rates offered on the big interbank venues, and futures prices from the relevant exchanges (since these seem to be designed to track Eurex, LIFFE, COMEX, NYMEX, ICE futures contracts). What is the mechanism that would keep prices in line? Is it simply that the market makers hedge in other markets and thus their risk is minimised by replicating those market prices as fast as possible? Lastly, by my reading of the API documentation, there is no explicit way to tell when other people's trades are executed on LMAX, except perhaps that size disappears from one side of the best bid/offer, or the best bid/offer move, but I guess that is indistinguishable from market makers or market takers removing liquidity by cancelling limit orders. Can anyone see a way to extract that information? (Whether that data would be of any value is maybe debatable).