Mirant Corp. on Friday posted a 97 percent plunge in its third-quarter profit _ driven mainly by one-time hedging losses _ and lowered its 2009 adjusted earnings before interest, taxes, depreciation and amortization.

Significantly low prices for commodities, including electricity, also challenged results for the Atlanta-based electric utility.

Quarterly earnings fell to $55 million, or 38 cents per share, compared with $1.61 billion, or $8.69 per share, during the same period last year.

Results include hedging losses along with other special items. Excluding one-time items, adjusted income from continuing operations amounted to $1.63 per share, exceeding analyst expectations.

Analysts surveyed by Thomson Reuters estimated a profit of $1.16 per share, on average. Analysts typically exclude one-time items.

Revenue fell 79 percent to $454 million, down from $2.17 billion in the prior-year period. Analysts forecast an average revenue of $734.3 million.

Mirant cut its 2009 EBITDA estimate to $860 million, down from $873 million. The company raised its 2010 EBITDA estimate to $617 million from $570 million.

Shares of the company fell 71 cents, or 4.8 percent, to $14 in afternoon trading.