I have seen lots of people talk about how much money they will make doing arbs between the SSFs and the underlying security because there are certain to be wide spreads from time to time. This is probably true, but keep a few things in mind. First, futures and cash do not trade at the same price except on and near expiration. So, purhaps you will see the QQQ at $25, but the QQQ futures at $25.15. Seems like a monster spread that will close, but that probably isn't the case. Also, there are probably a lot of other people with the same idea, many of them are probably using sophisticated computer algorithms to scan each tick in each of these markets for any arb. opportunity and they will probably take them fairly quickly. This is not to say an individual trader won't be able to arb, but just that, IMHO, its going to be very difficult.
Brandon