Thanks for your responses. I am searching the site under Liquidity Trading for more info. I personally think that it's possible to "trade to break-even" if your stock selection in proper. In other words, stocks like SIRI, CHTR, SUNW, since they trade so tight and so deep, I would guess you can automate a system to make or lose less than a penny (usually the spread is less than 1c in those stocks). Also, you should be effectively getting an "edge" by acting as a specialist or market-maker role. I think the rebates are $2 per thousand, if you can do 15 Million rebatable shares per day, isn't that like $30,000 per day, just in rebates? Obviously, you need to back out clearing costs, etc. Just curious about others opinions. Not trying to sell this idea, just thinking about doing it myself. Thanks!