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 SM Energy (NYSE:SM) fell as much as 19% after reporting and being downgraded by an analyst.

So what: Financial results from the fourth quarter showed a 46% increase in proved reserves to 428.7 million barrels of oil equivalent, or MMBOE, and adjusted fourth-quarter net income of $85.9 million, or $1.26 per share. The problem is that analysts were expecting $1.46 per share in earnings and that led KeyBlanc to lower its rating to hold and remove its price target.  

Now what: What's concerning analysts and investors is potentially higher costs in Eagle Ford resulting from longer lateral length drilling, which increases costs. That's a concern but consider that shares still trade at just 13 times forward estimates and the growth and cost cutting that SM Energy has in place has it on the right path. Rising energy prices will also help profits going forward, so I think there's more positive here than negative, and today presents a real buying opportunity.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.