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 EMC Corporation (NYSE:EMC) gained about 1% today after Wunderlich Securities initiated coverage on the data-storage giant with a buy rating.

So what: Along with bullish call, analyst Kaushik Roy planted a price target of $31, representing about 14% worth of upside to yesterday's close. So while contrarians might be turned off by the stock's strength over the past month, Roy's call suggests growing confidence on Wall Street over the sustainability of EMC's recent growth trajectory. 

Now what: According to Wunderlich, EMC's risk/reward trade-off is pretty compelling at this point. "The company is executing very well and has grown faster than the markets in which it is participating by gaining market share," said Roy. "We believe EMC can grow its revenues faster than the overall growth rate of the Information Technology market. EMC has solid cash flow from operations. The company has a strong management and technical team." When you couple those positives with EMC's still-cheapish forward P/E of 12, it's tough to disagree with Wunderlich's upgrade.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.