4. SunPower ( SPWRA) designs, manufactures and sells solar electric power technologies. For the first quarter of 2011, the company reported lower-than-expected revenue, driven by changing market dynamics in Europe. Revenue increased to $451.4 million from $347.3 million in the same quarter of 2010. Gross margin stood at 19.6% vs. 20.7% in the prior year's same quarter. Reviewing the company's performance, Tom Werner, SunPower CEO, said in a press statement, "We met our margin and bottom line financial goals in the first quarter by adjusting our downstream channels and operating expenses." Besides, SunPower has reduced its manufacturing costs for the quarter, and is likely to achieve the efficiency-adjusted panel cost per watt target of $1.08 in the fourth quarter of 2011. The stock delivered 32% returns during 2011 and is trading at 13 times its estimated 2011 earnings.