What? Casella Waste Systems (NASDAQ: CWST) watched as its shares sank 11.7% last month. At first blush that sounds ominous, especially since the shares of larger competitors Waste Management (NYSE: WM) and Republic Services (NYSE: RSG) barely budged. To understand what happened, however, you need to go just a little further back.

So what? Hauling trash and recycling has been a rough business since the 2007 to 2009 recession. For example, industry giant Waste Management's volumes have been generally flat to lower since 2010. Moreover, fierce competition has kept pricing power weak. And, as if that weren't enough, falling commodity prices have taken a big bite out of recycling profits. Declining revenue in Republic Services' recycling business, for example, is expected to by a $0.09 a share headwind to its full-year 2015 earnings.

So, perhaps, it shouldn't be too much of a surprise that relatively tiny Casella Waste Systems, offering a vital, asset heavy service dominated by Waste Management and Republic, attracted the attention of activist investors. JCP Investment Management, the "barbarian" storming the gate, has been invested in Casella since 2010 and in March of 2015 sent an open letter in an attempt to get its representatives elected to the trash hauler's board. Two days before the final proxy count was to take place, however, JCP withdrew its candidates... And Casella's shares jumped higher.

That, however, was November. And, as it stands, nothing changed on the business front between the vote and the end of the year. Which is likely why Casella's shares sank in December after the excitement of the contentious proxy vote waned. If you look at Waste Management, Republic, and Casella from November 1st to the end of the year, all three moved in lock step—with basically no material price changes over the span.

Now what? So, Casella's December drop is really much ado about nothing. This is not to say that there are no headwinds going forward. Trash haulers continue to face headwinds on the volume, pricing, and recycling fronts as previously noted. It's also worth pointing out that Casella's shares are still up around 30% since March, when the real excitement started with JCP. There very well could be further downside as we move into 2016 if investors hoping for swift change at this trash hauler move on to greener pastures. Given these risks, it's probably best to avoid this drama for now.