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 Merck (NYSE:MRK) climbed nearly 3% today after Morgan Stanley upgraded the drug giant from underweight to overweight.

So what: Along with the upgrade, analyst David Risinger planted a price target of $60 on the stock, representing about 15% worth of upside to Friday's close. While contrarians might be turned off by Merck's strong stock price in recent months, Risinger believes there's more room to run given management's recent strategic initiatives, as well as the optimism surrounding its immuno-oncology candidate, MK-3475.

Now what: According to Morgan Stanley, Merck's risk/reward trade-off is particularly attractive at this point. "Mgmt is taking the right steps -- cost cuts, R&D changes, and considering strategic action -- to boost company's outlook," noted Risinger. Of course, with Merck shares surging to yet another 52-week high today and trading at a P/E of 35, I'd wait for a much wider margin of safety before buying into that bullishness. 

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Fool contributor 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.