While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Nokia Corporation (NYSE:NOK) rallied 3% this morning after Jefferies upgraded the communications equipment giant from hold to buy.

So what: Along with the upgrade, analyst Lee Simpson raised his price target to 7.41 euros (from 5.34 euros), representing about 35% worth of upside to yesterday's close. So while momentum traders might be turned off by Nokia's price sluggishness in recent months, Simpson's call could reflect a sense on Wall Street that its intellectual property is just too cheap to pass up.

Now what: According to Jefferies, Nokia's risk/reward trade-off is rather attractive at this point. "Although the rerate in Technologies sales is further out (2014+) and HERE appears to need a new round of investment, we think the story on Nokia is a very promising one (future IPR potential, focused infrastructure play) with the math on IPR royalties offering an intriguing value upside," said Simpson. "Our expectation is that the firm, now shorn of its handset business, can charge an average royalty rate of 1.4-1.5% for essential patents alone." With Nokia shares now up about 120% over their 52-week lows and trading at a forward P/E of 20, however, I'd hold out for a wider margin of safety before betting on it. 

The biggest thing to come out of Silicon Valley in years
If you thought the iPod, the iPhone, and the iPad were amazing, just wait until you see this. One hundred of Apple's top engineers are busy building one in a secret lab. And an ABI Research report predicts 485 million of them could be sold over the next decade. But you can invest in it right now... for just a fraction of the price of AAPL stock. Click here to get the full story in this eye-opening new report.

Brian Pacampara has no position in any stocks mentioned, and neither does The Motley Fool. 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.