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 transportation equipment builder Wabash National (NYSE: WNC) are crashing today, falling as much as 10.3% on fairly average trading volume.

So what: There's no earnings report, no news item, not even a tweet on which to hang this drastic move. Then again, Wabash has been known to make sudden, inexplicable moves like this on a regular basis.

Now what: The company nearly died in 2009, suspending its dividend and hunkering down for a return to decent health. That nursing action worked out OK, which sparked massive optimism among the stock's owners and supporters. Large moves one way or the other often induce speculation and further instability, and Wabash is more than twice as volatile as your average stock. And that dividend is still nowhere to be seen. In short, we're watching market gamblers at play.

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