I know there have been some threads on this, but they all seem to be dead. I just wanted to share my experience trading these for the first time today. It was suggested on another thread that I might want to try SSF to deal with some trouble I was having shorting KLAC (thanks hii), so today I gave it a shot. I traded AMAT and NVLS - these were my impressions: Fills when buying at the offer or selling at the bid were immediate. Bids and offers between the spread were displayed immediately. There were usually 20 contracts per side (I was trading 2 or 4). The spread was about .08 or more most of the time. If it weren't for the big spread, these would be perfect. No down tick rule, better margin, immediate fills, and plenty of liquidity for me. Unfortunately, the spread is too big for me. I trade pairs, so it appears that the spreads will be prohibitive. If some of you guys will start trading them maybe we can get the spreads tightened up. I was going to try some listed stocks too - MER and MWD, but the spreads were too big. This would be a good way to get a short off when the spec is being a jerk though. I will watch some more, maybe when the spec spreads out the futures won't look too bad. Anyway, if the spreads tighten up, these will be awesome.