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.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.