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 Morgan Stanley (NYSE:MS) gained slightly Monday morning after Nomura Securities upgraded the financial holding giant from neutral to buy.

So what: Along with the upgrade, analyst Steven Chuba boosted his price target to $36 (from $33), representing about 17% worth of upside to Thursday's close. So while momentum traders might be turned off by Morgan's share-price sluggishness in recent months, Chuba's call could reflect a growing sense on Wall Street that its prospects are becoming too cheap to pass up.

Now what: According to Nomura, Morgan's risk/reward trade-off is rather attractive at this point. "While we believe that consensus remains too high for 2015E, Street numbers for '15E have rebased post earnings and now appear more reasonable," said Chuba. "Currently, we see limited downside to Universal bank shares; valuations and lower downgrade risk should provide support post recent momentum and earnings-driven weakness." When you couple that limited downside with Morgan's seemingly improving fundamentals, it's tough to disagree with Nomura's upgrade. 

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.