interesting ScottSam.... you are averaging about 500k shares per day then ? So if you are trading 5k lots on the average, that's 100 round turns per day. That's gotta be automated, right ? So your fee/commish is about $10k per day ?
Lots of these guys sit on the bid/ask with size using specialized routes. Its a form of rebate trading using a route that allows fill priority.
Echo pays 100%, best firm bar none, you get K-1 and they sell no training thus no conflict of interest issues. Bright will be second on my list solid firm, lots of liquidity also issues K-1.
Your statement implies that one doesn't get a K-1 with a CBSX firm? That doesn't sound right.... In any case I think it would be wise for Echo to start taking S56 traders. I'm surprised they haven't done so...