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: Dean Foods (NYSE: DF) is up 10% today on news that hedge fund manager David Tepper has built a large position in the company.

So what: Tepper made a fortune buying financial stocks at the bottom and is making another contrarian bet on Dean Foods, buying a 7.35% stake in the company. The stock has suffered a terrible fall since hitting highs in March 2007, but Tepper thinks the worst days are behind it.

Now what: Tepper is known for investing in volatile stocks, so buying into Dean Foods just because a big-name hedge fund manager is doing it isn't advised. However, I do like the contrarian pick and the low price-to-earnings ratio of 11 that Dean Foods has right now. I have to agree with Tepper on this one. I think Dean has hit rock bottom and is poised to continue its recent trend upward.

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