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 (Nasdaq: PCLN) rose nearly 12% in early trading and remained up more than 8% as of this writing. Last night, the online travel agent reported strong second-quarter profits and gave upbeat Q3 earnings guidance.

So what: Negotiating works. Second-quarter revenue rose 44% to $1.1 billion, while adjusted profit soared 79% to $5.49 a share. Analysts had been calling for just $4.87 a share on $1.07 billion in revenue, according to data compiled by Yahoo! Finance.

Now what: Guidance is what thrilled investors. Management told analysts to expect $9.10 to $9.30 in adjusted Q3 earnings, well above the $7.94 they had projected. Growth like that isn't easy to come by. So while I can't call cheap -- no stock trading for more than 25 times forward earnings ever is -- a 1.09 PEG ratio says this is a five-star stock trading at a three-star valuation. Do you agree? Disagree? Weigh in using the comments box below.

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