Think they are pairing the QQQs against a basket of Nas stocks? This would account for the large Q volume on their ECN, and the one stock mentioned where they did alot of volume is MSFT. Another thing about their "edge" or "secret". There really is nothing new under the sun and alot of big moneymakers - they have an edge, but it has little to do with predicting stock price movements. If they are adding liq at the current rebate rates, which is higher per share than clearing fees that they get doing such huge volume, they could very easily gross 0 from their trading and still make a profit. Breaking even on trades: 100 million shares * .0005 (.002 rebate - .0015 clearing, etc..) = $50,000/day The whole "what's their moneymaking secret" so misses the point. There are no secrets, a fact that is obscured by all those frauds who are trying to sell you a way to predict the future.