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 HCA Holdings (NYSE: HCA) climbed 10% today after announcing plans to buy back about $1.5 billion worth of shares from one of its lead underwriters, Bank of America (NYSE: BAC).

So what: We Fools love stock buybacks since they serve to reduce the number of shares outstanding and, in turn, increase earnings per share and the percentage stake that owners have in the company. Given that HCA will be repurchasing a significant 16% chunk of its float (80.8 million shares for $18.61 each), it's no surprise that Mr. Market is looking to get ahead of the boost in value.

Now what: I wouldn't get too excited about HCA just yet. The buyback is certainly a shareholder-friendly move on management's part, but HCA continues to face a significant slowdown in profitable procedures, as well as the very real possibility of looming Medicare cuts. While it's great that HCA's leveraged buyout overhang is gone, the main risks surrounding its business remain.

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