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

What: Shares of Emerson Electric Co. (EMR -0.02%) climbed about 3% today after Oppenheimer upgraded the diversified industrial company from perform to outperform.

So what: Along with the upgrade, analyst Christopher Glynn planted a price target of $77 on the stock, representing about 20% worth of upside to yesterday's close. So while momentum traders might be turned off by the stock's weakness in recent months, Glynn's call could reflect a growing sense on Wall Street that Emerson is becoming too cheap to pass up.

Now what: According to Oppenheimer, Emerson's risk/reward trade-off is rather attractive at this point. "We have regarded directional momentum of Network Power and Industrial Automation as linchpins for prospects for EMR shares to outperform, and view prospects for inflection now established," said Glynn. "NP's and IA's strategic and cyclical positioning looks much improved, supporting prospects for multiple expansion and EPS upside over the next two years." When you couple that upbeat outlook with Emerson's sluggish price action and near-3% dividend yield, it's tough to disagree with Oppenheimer's upgrade.