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 trucker YRC Worldwide (Nasdaq: YRCW) jumped as much as 20% in intraday trading on heavy volume.

So what: In its efforts to get back on its feet, the last thing YRC needed was a competitor doing its darndest to further hobble the company through the courts. But there it was, Arkansas Best (Nasdaq: ABFS) subsidiary ABF Freight Systems filing suit saying that the concessions that YRC had negotiated with the Teamsters violated the National Master Freight Agreement. Fortunately for YRC and its shareholders, a motion to dismiss has been granted by a U.S. District Court judge.

Now what: While the dismissal is good reason for a sigh of relief, it's uncertain that ABF will let the issue go. A post-ruling statement from ABF suggests that it may seek an appeal. It'll be interesting to see whether ABF does pursue the suit further, as the Teamsters are staunchly behind YRC and the negotiated deal that's at issue here. Regarding the dispute, the director of the Teamsters National Freight Division said: "ABF should concentrate on freight pick-up and delivery operations of its company rather than trying to put YRCW out of business through litigation and other means." Oh snap!

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy assures you no Wookiees were harmed in the making of this article.