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: NetScout Systems (Nasdaq: NTCT) dropped 20% in intraday trading today after guiding down expectations for the just ended quarter and fiscal year.

So what: Management is now expecting non-GAAP EPS of $0.11 to $0.13 for the just ended quarter (down about 43% year over year) and $1.07 to $1.19 for fiscal 2012, which ends in June 2012. The consensus estimates before last night's announcement were calling for non-GAAP EPS of $0.20 and $1.19, respectively. Revenue expectations were also set below the consensus forecast. Management is now expecting $62 million to $64 million for the just ended quarter (down about 6% year over year) and $300 million to $315 million for fiscal 2012. The consensus forecasts before last night's announcement were calling for $72 million and $329 million, respectively.

Now what: The company plans to release full results for the just ended quarter on July 21. It blamed the disappointment on government budget holds and pressure on its financial services customers, noting it had trouble signing new business during the quarter. With governments working to slash budgets and no end in sight with the pressure on financial services companies, improving the bottom line may rely on what the company can control -- cost cutting.

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Fool contributor Cindy Johnson does not own shares of any company named above. 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.