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13. Constellation Energy
13. Constellation Energy
Fortune 500 rank: 172
2010 loss: $982.6 million

After a $1.3 billion loss in 2008, the Baltimore-based energy company managed to swing to a profit in 2009 before plunging back into the red last year.

Income grew at Constellation's supply and services business and at its electric and gas public utility. But problems arose in its power generation division, which includes its nuclear businesses. The company recorded charges on its investment in its nuclear units partly due to the decline in power prices during the third quarter of 2010 and uncertainty around how potential environmental laws will impact pricing.

NEXT: 14. Great Atlantic & Pacific Tea
Last updated May 05 2011: 3:06 PM ET
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