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 RPC (NYSE: RES) fell as much as 10% today after the company released earnings.

So what: Normally when a stock falls this far, it misses expectations by a mile, but RPC was actually better than analysts expected in the second quarter. Revenue of $443 million beat estimates of $410.5 million, and earnings per share were in line with expectations at $0.50.

Now what: So why the fuss today? Higher revenue and profit in line with expectations means margins were lower than expected -- that’s what investors are focused on today. Management pointed to higher costs for materials and maintenance costs for the lower margins. Before we panic too much here, I will point out that earnings were in line with expectations, and the stock is only trading at 10.6 times forward earnings estimates, so this price dip looks like a buying opportunity to me.

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