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 United States Steel Corporation (NYSE:X) climbed 5% today after KeyBanc upgraded the steel producer from Hold to Buy.

So what: Along with the upgrade, analyst Philip Gibbs planted a price target of $37 on the stock, representing 25% worth of upside to the previous close. While value investors might be turned off by U.S. Steel's sharp rise since the summer, Gibbs believes that several company-specific and macro factors will continue to fuel the stock in 2014.

Now what: KeyBanc boosted its 2014 EPS estimate for U.S. Steel from $1.65 to $2.05, well ahead of the Wall Street consensus of $1.21. KeyBanc noted:

[W]e believe shares have more room to run based on our positive carbon hot-rolled steel pricing revisions for 2014: meaningful raw material cost tailwinds (coal, scrap, iron ore); low Street EPS and EBITDA expectations for 2014-2015; an ever-increasing interest rate environment (benefits for pension exposure); more evidence of European macro stability; and above-average likelihood of incremental operational efficiency announcements such as a joint venture or tolling agreement with Allegheny Technologies Incorporated.

With the stock now up nearly 100% from its 52-week lows and trading at a forward P/E of 25, however, it's hard to believe those positives aren't already baked into the price.

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.