20 companies that lost the most

The story of Energy Future Holdings, of one of the nation's largest energy providers, has been a debacle of historic proportions. When private-equity power players bought the TXU Corp. (it was later renamed) in2007, it was the largest leveraged buyout ever. KKR & Co., TPG Capital and a division of Goldman Sachs led the charge in a deal that was valued at $45 billion. With the buyout, the firms were gambling that the price of natural gas, the energy giant's forte, would continue to rise. Even Warren Buffett got in on the deal, buying $2 billion in TXU bonds.

It was not a good bet. After 2007, the private equity boom receded, credit tightened, and natural gas prices plummeted. With new gas discoveries and the rise of fracking, natural gas prices tumbled well below the company's break-even point. In a letter to shareholders, Buffett said his TXU bonds were at risk of losing all of their value.

Today, the Houston-based provider employs some 9,000 people and serves millions of Texas customers. It also has a balance sheet laden with some $35 billion in debt from the buyout that will come due in 2014. Now with a CC credit rating Fitch, the company's chances of avoiding default look slim.

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