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 Greenbrier (NYSE: GBX), a maker of railcars, continued a slide that started yesterday falling as much as 11% in trading today.

So what: Quarterly numbers released yesterday were stronger than expected, but management's comments were cautious at best. An expected slowdown in the fracking market put a halt to higher trading yesterday and contributed to losses today. But the big catalyst was Susquehanna's lowering of its price target on the stock from $28 to $21.

Now what: Let's keep in mind that the company just crushed estimates and $21 per share is still a 24% upside from where shares are trading today. The market has certainly panicked over a potential slowdown in one of the company's end markets, which was running at such a frenetic pace that it would eventually have to slow down. Shares may be volatile for a few days, but I see this as a great buying opportunity for the long-term investor. The company has now crushed estimates for three straight quarters, and shares are trading at just 6 times next year's expected earnings. That sounds like a great discount to me.

Interested in more info on Greenbrier? Add it to your Watchlist.

Fool contributor Travis Hoium has no position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings, or follow his CAPS picks at TMFFlushDraw.

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