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: Research In Motion (Nasdaq: RIMM) dropped 23% in intraday trading today after issuing disappointing earnings guidance for the full year and announcing layoff plans.

So what: Although first-fiscal-quarter EPS of $1.33 was in line with April's lowered guidance, revenue fell short of the consensus forecast -- and management's April guidance -- of $5.2 billion. BlackBerry sales of 13.2 million units were below the low-end of guidance, although 500,000 PlayBook tablets shipped during the quarter, well ahead of analysts' average estimate of 400,000. Management has begun a restructuring program, including job cuts, which it expects will begin helping the bottom line in the third quarter.

Now what: Research In Motion has been losing share to Apple's (Nasdaq: AAPL) iPhone and to Android phones. It doesn't expect to ship its next version of BlackBerries until near the end of the current quarter. For the current quarter, management said it expects EPS if $0.75 to $1.05 on revenue of $4.2 billion to $4.8 billion, well below the consensus forecasts of EPS of $1.40 and revenue of $5.5 billion. The wide range of EPS guidance for the quarter and the restructuring program suggest management is finally grasping the seriousness of the company's deteriorating situation, though it may be too little or too late. For fiscal 2012, which ends next February, management lowered EPS guidance from $7.50 to between $5.25 and $6.00. Collateral damage in today's stock market includes contract manufacturer Celestica (NYSE: CLS), which gets 21% of revenue from RIM, and Marvell Technology Group (Nasdaq: MRVL), which supplies chips for BlackBerries.

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