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 CVR Energy (NYSE: CVI) are popping 13% higher on news that a high-profile hedge fund has been adding shares of the company.

So what: Appaloosa Management, a hedge fund managed by David Tepper, increased its position in CVR Energy from 1.56 million shares to 7.33 million shares in the second quarter. CVR Energy was among the largest additions to the company's portfolio along with Valero Energy (NYSE: VLO) and Mosaic (NYSE: MOS).

Now what: Buying a stock just because a big hedge fund manager does isn't very sound investing, but if you want to get in, I would look at the value. Shares are currently trading at 11.3 times trailing earnings and 9.1 times forward earnings estimates. If you're thinking about buying shares of CVR Energy, I would do it because of that value and not because a hedge fund manager has a position. He could disappear as fast as he bought shares.

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