Tell me if you guys agree with this... if you are going to provide liquity normally you'd like to provide on ARCA or an ECN that pays you for providing rather than on NYSE which pays you nothing... However, the cost of entering the market on a limit order (bidding or offering) is dependent on where you are in line. NYSE orders will normally get filled first and then the ECNs will get filled due to the fact that people want to take on NYSE. So you are receiving the 25 cents / 100 on ARCA, but my guess is the "cost of entering" on limit is roughly equal to 25 cents / 100 more than the "cost of entering" on NYSE... in the end it all evens out! agree? comments?