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: Hewlett-Packard (NYSE: HPQ) dropped 23% in intraday trading today after issuing disappointing guidance and revealing plans to "transform" the business.

So what: Third fiscal quarter non-GAAP EPS of $1.10 rose a modest 2% year over year and beat the $1.09 consensus estimate. Revenue of $31.2 billion grew only 1% year over year, helped by currency exchange rates.

Now what: Fasten your seatbelt: It's complicated. Management retracted guidance for fiscal year 2014, which it issued just last March. For the current quarter the company expects non-GAAP EPS of $0.44 to $0.55, well below the $1.31 consensus estimate. To transform the company, it's killing the tablet and smartphone hardware business it bought in July 2010 and hoping to salvage the webOS software that came with the $1.2 billion purchase. It's considering selling or spinning out its PC business and agreed to pay about $11 billion to buy software maker Autonomy. The transformation is expected to take a number of quarters and pressure earnings during that time. At a P/E ratio of 5.9 times, the stock may appear to be a great value, but it could well be a value trap.

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