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 online-deal maven Groupon (Nasdaq: GRPN) were charging up today, rising as much as 13% in intraday trading.

So what: Groupon's big run came on the heels of an upgrade from Morgan Stanley analyst Scott Devitt, who upgraded the stock from "equal weight" to "overweight" on the view that the company has gotten better at targeting deals for customers while significantly cutting expenses. He also said deep-pocketed competitors such as (Nasdaq: AMZN) and Google (Nasdaq: GOOG) have lost a step on Groupon.

Now what: This is a nice vote of confidence for Groupon investors, after the company has been on the receiving end of significant bad press since its IPO. However, it's important to bear in mind that this is just the view of a single analyst -- and an analyst from Groupon's lead IPO underwriter, no less. So today's upgrade could be a good reason for investors to revisit their assumptions on Groupon, but it needs to be taken with a grain of salt and isn't alone enough to pull the trigger.

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