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 Westlake Chemical (NYSE: WLK) fell 15% at the opening of the market today after the company released earnings.

So what: Revenue rose 24.2% to $968.4 million, easily surpassing estimates from analysts of $910.9 million in revenue. Earnings per share of $1.01 also beat estimates by $0.03, so the quarter was very good overall.

Now what: Much of the loss has already been recovered, and shares are currently down just 6%. Sales prices were up 29% during the quarter, showing strong demand, so the drop this morning was a bit puzzling. I think this dip presents a great buying opportunity, as shares trade well below 10 times 2011 earnings estimates.

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Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

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