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 Capital One Financial (NYSE:COF) gained 1% this morning after Nomura Securities upgraded the credit card giant from neutral to buy.

So what: Along with the upgrade, analyst Bill Carcache planted a price target of $94 on the stock, representing about 16% worth of upside to Friday's close. So while contrarian traders might be turned off by Capital One's price strength over the past year, Carache's call could reflect a sense on Wall Street that the company's margin expansion prospects give the stock more room to run.

Now what: Nomura raised its 2014 earnings-per-share estimate for Capital One from $6.86 to $7.08 and its 2015 view from $7.14 to $7.59. "Since the beginning of 2013, COF shares have underperformed AXP / DFS by 26% / 21%," noted Carcache. "Looking ahead, we expect COF's performance to improve, as loan growth resumes and P&L expense headwinds turn into tailwinds." When you couple that upbeat outlook with Capital One's industry-lagging P/E of 11, it's tough to disagree with Nomura's bullishness. 

Brian Pacampara has no position in any stocks mentioned. The Motley Fool owns shares of Capital One Financial. 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.