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 travel agency (NASDAQ:BKNG) soared 12% today after the company's quarterly results and guidance topped Wall Street expectations.

So what: The stock has slumped in recent months on worries over slowing growth amid the weak global economy, but today's third-quarter beat -- EPS jumped 27% to $11.66 versus the consensus of just $10.90 -- naturally eases some of those concerns. In fact, gross travel bookings during the period surged 25% to $7.8 billion, suggesting that its important European business -- representing 60% of the hotel room nights it books -- is at least beginning to stabilize.

Now what: Management now sees fourth-quarter adjusted EPS of $6.12-$6.57 and revenue of $1.14 billion-$1.21 billion, versus the average analyst estimates of $6.32 and $1.14 billion, respectively. "Given the uncertainties surrounding worldwide economic conditions, particularly in Europe, where much of our business is concentrated, and the negative impact of Hurricane Sandy, we believe the variability around our guidance is elevated," cautioned CFO Daniel Finnegan in a conference call. When you couple those economic headwinds with the increasingly intense competition in the space, buying into today's big rally doesn't exactly seem like a prudent move.

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