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 business-class GPS gadget designer Trimble Navigations (Nasdaq: TRMB) found their way to gains as high as 11.6% today. The upward trend continued on heavy volume into the afternoon hours.

So what: As of last night, a wee-long fall had taken a 22% toll on Trimble's value -- until JPMorgan Chase upgraded the stock to a "buy." The upgrade appears to be based on valuation, as Morgan kept its price target on Trimble steady at $53.50.

Now what: Trimble reported decent earnings with a weak outlook a week ago, sending the stock on a downward slide that was exacerbated by a much stronger report from Garmin (Nasdaq: GRMN) this Wednesday. This is a story of dueling analysts: That first-quarter report was greeted by two immediate downgrades and one reiterated "buy" before JPMorgan Chase decided to join the party. Our Foolish analyst teams are siding with the bears on this one, as two newsletters have decided to short the stock, and Trimble also rates a single star out of five in our CAPS system. There's not a whole lot to love here.

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