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 Michael Kors Holdings (NYSE:CPRI) have slipped more than 3% so far today after Citigroup downgraded the fashion apparel and accessories specialist from buy to neutral.

So what: Along with the downgrade, analyst Oliver Chen lowered his price target to $93 (from $95), representing about 13% worth of upside to yesterday's close. While momentum traders might be attracted to the stock's sharp rise over the past year, Chen believes that sluggish watch sales of late -- from both Macy's and Fossil -- suggest that Michael Kors' 2014 won't be quite as spectacular.

Now what: According to Citigroup, Michael Kors' risk/reward tradeoff isn't too appealing at this point. "We're lowering our rating to Neutral based on the view of fairer intrinsic valuation given KORS' +60% stock run in 2013, strong comps which will likely still exceed guidance (+15-20%) but to a lesser extent, accessory sector read-throughs which convey a possibility of lack of upside," noted Citigroup. When you combine those concerns with Michael Kors' 30-plus forward P/E, it's tough to disagree with Citigroup's cautious stance.