So I managed to do a very small scalp as a test during the melt down friday morning. Basically I had a option spread on a stock where the deep in the money put spread bid was max. Meaning lets say the stock is trading at 10 bucks and the 31/30 put spread had a bid of $1.00. So if I sell this then I would normally have a margin requirement of $100....but I also received $98 (paid 2 bucks for commission). So I got hosed because even though this really doesn't affect my margin, my buying power fell by 400 bucks? WTF? I ended up with no buying power ability even though I had really just paid 2 bucks in commissions for a trade so how does paying 2 dollars equate to 400 dollar reduction in buying power?