During 2004-2005, the firm shifted its emphasis to energy trading, led by the success of Canadian trader Brian Hunter who invested in the natural gas market.

Hunter's prominence in the firm also raised calls for caution from both inside and outside Amaranth by those who worried being concentrated in a single volatile commodity introduced major risks.

[2] Hunter, who was 32[4] years old at the time, invested heavily in natural gas futures which resulted in a single week loss of $6.5 billion when prices failed to move as expected.

[7] On Monday September 18, 2006 Amaranth Advisors told investors that natural gas market downturn had resulted in $3 billion of losses.

"[2] Traders sold securities that could be liquidated without undermining and disrupting the energy market; these included convertible bonds and high-yield corporate debt.

Judge Carmen Cintron found that "Hunter intentionally manipulated the settlement price of the at-issue natural gas futures contracts.

[13] In November 2007 Amaranth Advisors filed a lawsuit against JPMorgan claiming $1 billion in damages on the grounds that the bank interfered in the company's efforts to avoid collapse after natural-gas trades losses in 2006.

When it bet big on natural gas and lost, it was apparent that it was neither multistrategy nor particularly well hedged"[7] and also that in Amaranth Advisors' case " 'multistrategy' seems to have been a misnomer at the fund.