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 giant Community Health Systems (NYSE: CYH) popped 17% on Tuesday, just a day after plunging sharply on allegations that it systematically ripped off the Medicare system.

So what: Yesterday, the accusations made by rival Tenet Healthcare (NYSE: THC), which my fellow Fool Matt Koppenheffer labeled as "very serious," fueled a massive one-day decline of 36% in Community Health's shares. With a night to think about it, however, Mr. Market seems to be listening a little more closely to Community Health's side of the story, which views the allegations as just another feeble attempt by Tenet to fight off its hostile takeover plans.

Now what: I'd continue to stay on the sidelines at this point. While reaction from Wall Street analysts have been fairly mixed, it's clear that Tenet's accusations -- justified or not -- will likely lead to increased scrutiny and action from regulators. Unless you're willing to cope with these extreme gyrations associated with so much uncertainty, Community Health doesn't seem like the most pleasant stock to own.

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