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 hospital operator Community Health Systems (NYSE: CYH) were looking mighty healthy after tacking on a 19% intraday gain.

So what: It's somewhat unusual to see an acquirer's shares rise when a deal is proposed, but that's exactly what's happening for Community Health. The hospital giant made a $3.3 billion hostile bid for competitor Tenet Healthcare (NYSE: THC), which sent Tenet's shares surging 55% and put some pep in its own shares as well. Though hostile deals can sometimes get messy, from a shareholder's perspective they're often a better way to go, since the acquirer may be able to squeeze out a better price than it would have gotten with a back-patting boardroom agreement. Sounding like the consummate dealmaker, Community Health CEO Wayne Smith quipped, "We have been accused of being opportunistic, and we are. That's what we do, and we will continue to do it."

Now what: Tenet has spurned the bid, claiming that it undervalues the company, while Community Health has pledged that it is committed to getting the deal done. There could be some interesting drama ahead, and it won't be too surprising if Community Health ends up raising its bid -- investors have already pushed Tenet's stock well past the proposed $6 takeout price. Community Health shareholders will certainly want to keep a close eye on this, and make sure that Smith's opportunism doesn't turn into a crusade with an uncomfortably high price.

Want to keep up to date on Community Health? Add it to your watchlist.

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 assures you no Wookiees were harmed in the making of this article.