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 KapStone Paper and Packaging Corp. (NYSE: KS) traded as much as 11% lower today after the company released earnings.

So what: Sales increased 17% to $206.7 million, and net income jumped 137% to $15.1 million, or $0.32 per share, this quarter. That fell slightly short of the $207.9 million in sales and earnings per share of $0.35 that analysts had expected.

Now what: Shares have been trending lower all day after a spike this morning. But the earnings miss wasn't by a wide margin, and the company's growth, along with increased prices this quarter, should help future earnings. I think today's discount is a great buying opportunity, and the company's 11.6 estimated 2011 earnings multiple is very attractive given the company's growth.

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