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 water infrastructure manufacturer Mueller Water (NYSE: MWA) did their best geyser impression today, shooting up as much as 12% in intraday trading.

So what: As noted by Rash Menaria on Seeking Alpha, Appaloosa Management -- the hedge fund of noted value investor David Tepper -- disclosed that it has acquired a 5.77% stake in Mueller. The stake could make Appaloosa the largest owner of Mueller stock, ahead of Invesco (NYSE: IVZ) and BlackRock (NYSE: BLK) which, at the end of last year, held positions of 5.6% and 5.5%, respectively.

Now what: For Foolish investors, Mueller, though small, is far from a new name. The stock is not only a pick at Motley Fool Hidden Gems, but it also currently has a perfect five-star rating on CAPS. Couple this with the more recent vote of confidence from Tepper, and you have good reason to take a look (or a second look!) at the stock. Of course, it bears noting that Tepper's purchase alone isn't enough of a reason for you to go out and grab some Mueller, so make sure you dig in with some of your own research.

Want to keep up to date on Mueller Water? Add it to your watchlist.

BlackRock is a Motley Fool Inside Value pick. Mueller Water Products is a Motley Fool Hidden Gems recommendation. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.