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 upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Deere (NYSE:DE) slipped nearly 1% today after Longbow Research downgraded the farm equipment manufacturer from neutral to underperform.

So what: Along with the downgrade, analyst Eli Lustgarten planted a price target of $80 on the stock, representing about 15% worth of downside to Friday's close. So while momentum traders might be attracted to Deere's price surge in recent months, Lustgarten's call could reflect a sense on Wall Street that the company's risks are now being largely overlooked. 

Now what: According to Longbow, Deere's risk to reward trade-off is rather unfavorable at this point. "While we expected 1HF2014 to hold up based on 2013 orders and farm income, demand has clearly begun to deteriorate leading to likely more significant weakness both in North America and globally in F2H14 and F2015 than expected," said Lustgarten. When you couple that downbeat outlook with Deere's red-hot stock price, it's tough to disagree with Longbow's cautious stance. 

Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.