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 health care services provider Accretive Health (NYSE: AH) were looking quite healthy to investors today, as they rose as much as 20% in intraday trading after a Wall Street upgrade.

So what: UBS (NYSE: UBS) rode in on the white horse for Accretive shareholders today, giving the stock a sweet buy recommendation in new coverage. Though the thumbs-up from UBS gave the stock a huge boost early in the day, that waned as the day wore on and the gain had dwindled to 4.5% as of this writing.

Now what: There's certainly good reason for investors to be excited about a new buy rating on Accretive's stock. However, the opinion of UBS doesn't change the underlying value of Accretive the company. For that reason, it may not be all that surprising that much of the early pop on the stock has disappeared. Foolish investors who are watching Accretive can take some additional confidence from UBS' view, but their best bet is to continue to focus on the company's execution and how it's able to build value.

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