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 Willbros Group Inc (NYSE:WG) are up more than 13% today following the company's fourth-quarter earnings report after yesterday's closing bell. You'd be hard-pressed to say why, because none of the company's results, nor its guidance, appear particularly noteworthy.

So what: Willbros reported $540.5 million in revenue, and broke even on the bottom line for the fourth quarter for its continuing operations, which was significantly weaker than the $0.13 in earnings per share that analysts had expected. The company's operating income was $15.5 million for the quarter, and $34.1 million for the year. On a full-year basis, Willbros posted a $0.48 loss per share on revenue of $2.0 billion for 2013. The full-year loss included a one-time debt extinguishment charge that tacked on $0.24 per share in losses.

Looking ahead, Willbros expects to generate between $2.1 billion and $2.3 billion in revenue for fiscal 2014, which comes in narrowly ahead of the $2.17 billion consensus estimate at the midpoint. The company expects its operating results to improve "significantly," according to CFO Van Welch, but that's as much detail as you'll get as far as any bottom-line guidance goes.

Now what: Full-year estimates now anticipate Willbros earning $0.77 in EPS for 2014, so "significantly" may be only a starting point for the company. The company is already expecting a weather-related sequential decline in earnings for the first quarter, but has three new midsized pipeline projects to undertake this year that should help its weakened Oil & Gas segment rebound from a lousy year (virtually all of the company's revenue growth came from its Canadian operations).

If Willbros can earn $0.77 this year, it would peg the stock's P/E at a modest 12.9 -- but without any clearer guidance than "significant" growth, it's hard to justify today's pop. I'd wait for more clarification before diving in.

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Alex Planes has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.