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 Thor Industries (THO 1.93%) sank 11% today after the recreational vehicle maker's quarterly results disappointed Wall Street.

So what: Thor shares have surged over the past few months on signs of rebounding RV demand, but today's first-quarter miss -- EPS of $0.58 versus the consensus of $0.63 -- is forcing analysts to dial back their enthusiasm. Management blamed the lackluster results largely on increased discounting caused by intensifying competition, suggesting that its margins remain under pressure despite the recent uptick in demand.

Now what: Don't expect the short-term headwinds to let up anytime soon. "Although we have seen a recent upturn, we remain cautious given the overall economic uncertainty," Chairman Peter Orthwein said. "In addition, both the RV and bus markets remain very competitive, with elevated levels of discounting." With the stock still up about 75% from its 52-week lows, I'd wait for an even bigger pullback before taking on those risks.

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