My guess is that so many traders will be using them as a surrogate for the market (i.e. Lower margin and no tick test) that the real winners will be the ones who can set themselves up to take advantage of the demand for liquidity at stressful or pivot points in the market. Those traders who can afford to trade the stock from a capital and regulatory standpoint (Bullets) and can be a provider of liquidity to the SSF's (buy on the bid and sell on the offer) at the market turns can make great money trading the futre and the stock as a riskless pair. Don, will the bd have reduced margin, pure arb, if they have set up the future versus the stock? Big benefit to leverage (the BD) if that is the case.