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 Alcoa Inc (NYSE:AA) surged 7% today after JPMorgan upgraded the aluminum giant from neutral to outperform.

So what: Along with the upgrade, analyst Michael Gambardella boosted his price target to $15 (from $9), representing about 32% worth of upside to Friday's close. While contrarians might be turned off by the stock's hot run of late, Ossenbeck believes there's plenty of room to run given the tightening supply conditions and escalating regional premiums in the aluminum market.

Now what: According to JPMorgan, Alcoa's risk/reward tradeoff is particularly juicy at this point. "Our Global Commodities Research team revised their aluminum supply/demand model on January 17th following recent producer capacity curtailments and changes to their view of China's likely production profile, which reduced the team's 2014 global primary surplus estimate by 364k tonnes to a 435k tonne surplus," Gambardella noted. "While China should see a 1.5mm tonne surplus this year, the rest of the world should actually have a 1.1mm tonne deficit in 2014." With Alcoa now up about 60% from its 52-week lows and trading at a 20-plus forward P/E, however, waiting for a wider margin of safety before betting on it seems like the prudent move.