I usually trade options on the OEX when I want to trade moves in the general market, but have been looking at the S&P emini's as they appear much more liquid for quick moves. I'm having a little trouble determining margin requirements on the S&P and Dow emini's. I have read where margin requirements were as little as $500/day on ES but thought I had also read where they were 1/5 the value of the index times the multiplier( which would be about $12,000 margin at these levels). I also don't see a difference in the margin requirements for being long or short. If someone has a minute and could set me straight on this I would appreciate it.