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 oil and gas well site servicer Basic Energy Services (NYSE: BAS) traded as much as 10% lower today on above-average volume.

So what: Basic Energy Services is not alone in its misery today as peers Newpark Resources (NYSE: NR) and RPC (NYSE: RES) also took heavy falls. However, none of these moves come with easy explanations, and mum's pretty much the word among the true giants of the energy industry today as well.

Now what: Before this fall, Basic Energy Services had climbed 21% in the last month alone and nearly 65% in three months, with Newpark and RPC not far behind. Slipping oil prices give nervous or greedy investors a great excuse to take some profits after a run like that, and crude oil prices did decline by 1% today. That's a transient effect, and I wouldn't be surprised to see the climb resume in short order -- with or without support from increasingly expensive oil barrels.

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Fool contributor Anders Bylund holds no position in any of the companies discussed here. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.