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 producer Newfield Exploration (NYSE:NFX) fell 15% today after reporting earnings.

So what: Third-quarter revenue fell slightly to $615 million, below estimates of $652 million. Adjusted earnings per share were $0.48, just below estimates of $0.51.

What the adjusted results don't include is a $135 million derivative loss, which swung the company to a $33 million loss.

Now what: Management also said that international production may be down 25% next year, which appears to be getting a lot of investor attention. I'm looking at the GAAP loss of $33 million as a great reason to sell today and will overlook the adjusted results. Many companies continue to lose their shirts on derivative "hedges" and I don't like exposure to these kind of losses.

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