4plexowner nailed it! On august 9, Bush’s buddy Paulson converted the Goldman Sachs Commodities Index oil weighting downward, causing billions of dollars of oil to be sold off.
Remember, oil was high based on futures trading! With the futures price donw, voila; lower gas prices.
When oil fell, natural gas followed, and that’s what screwed Amaranth.
As CR said, it helps to have friends in high places.