4. Calpine ( CPN), an independent wholesale power company, owns and operates natural gas-fired and geothermal power plants in North America. The company's portfolio of power generation technologies consists of natural gas-fired combustion turbines, which are primarily combined-cycle plants, and renewable geothermal conventional steam turbines. A consensus estimate of analysts polled by Bloomberg expects recording sales of $1.48 billion in the second quarter of 2011, compared to $1.43 billion in the same period of 2010. Net loss during the quarter is seen narrowing down to $5.22 million or breakeven per share as compared to a loss of $42 million, or 9 cents a share, in the same quarter prior year. Return on assets during the quarter is seen expanding to 1.22% from 0.17% earlier. Operating profit is estimated to double to $253 million. Of the 15 analysts covering the stock, 11 recommend a buy while 3 suggest a hold. Analysts polled by Bloomberg foresee the stock gaining an average 15.8% to $19.36 in the upcoming 12 months.