Quote from eugenie98:
Thinking about the Amaranth spread trade, it's not really any less risky if you use full margin, since spread trades have only a $2300 per NG spread maintenance margin requirement versus $10700 per contract for a one sided trade, so you can increase your exposure five times over with the same amount of capital. So a $1 change in the spread would be equivalent to a $5 change in the underlying (if doing a one sided trade). Additionally, trading the same amount of capital via a spread position would require about 10 times as many contracts as a one sided bet, and if you do that with far out contracts as in Hunter's case you have a big arse liquidity problem.
In Brian Hunter's case I think there was a $1.20 -$2 decrease in the spread between March and April 2007 (March dropped closer to April's price, from March being +$2.40 above April to $1.20), so I guess that highlights how he was screwed, that's like a $6-$10 loss in a straight one sided trade.
March has actually crossed under April now so the spread is going the other way, April is more expensive than March, whereas Hunter was betting March would remain more expensive than April and become even more expensive than April as time wore on.