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What: Shares of Guidance Software (NASDAQ:GUID) have plunged today by as much as 25%, after the company reported earnings.

So what: Revenue in the fourth quarter added up to $36.2 million, with non-GAAP earnings per share of $0.17. The bottom line result was slightly better than expected, which partially offset the disappointment from the top line miss, as investors were expecting $37.2 million in sales.

Now what: Guidance's guidance left a little to be desired, with full year revenue expected to be in the range of $144 million to $148 million, the midpoint of which is short of the $147.4 million consensus estimate. Non-GAAP earnings per share should be $0.25 to $0.30, which is well below the $0.50 per share in adjusted profit that analysts thought was in order.

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Fool contributor Evan Niu, CFA 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.