Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of SunPower (NASDAQ:SPWR) jumped as much as 10% in early trading today after it was announced that Warren Buffett would buy one of its solar projects.

So what: Berkshire Hathaway's (NYSE:BRK-A)(NYSE:BRK-B) MidAmerican Energy unit will spend between $2 billion and $2.5 billion to buy the  Antelope Valley projects SunPower is building. The projects will have 579 MW of capacity and are due to be complete in 2015.

Now what: This is the second big solar buy from Buffett, who also bought hundreds of megawatts in projects from First Solar (NASDAQ:FSLR). For SunPower, it's an assurance that there's a buyer for the biggest project it has started. This is just another sign that solar is here to stay, and SunPower will be one of the leaders going forward.

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