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 analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of M/A-Com Technology Solutions Holdings (NASDAQ:MTSI) closed down 8% yesterday after Goldman Sachs downgraded the analog semiconductor company from buy to neutral.

So what: Along with the downgrade, analyst Mark Delaney reiterated his price target of $17, representing about 4% worth of upside to where the stock sits now. The stock has soared over the past year on better-than-expected growth, but Delaney thinks that current valuation leaves investors with limited appreciation potential.

Now what: While Delaney remains bullish on M/A-Com's growth prospects, it expects the stock to come under pressure. "We downgrade M/A-COM (MTSI) to Neutral from Buy due entirely to valuation, as the stock is trading above our 12-month, $17 price target (which is unchanged and based on 15X normalized EPS of $1.15), and our estimates are in line to modestly above the Street," noted Delaney. "Since adding MTSI to the Buy List on 9/6/12, the shares are up 53% vs. the S&P 500 up 17%." When you couple that hot performance with M/A-Com's small size, intensely competitive environment, and volatile shares, I'd agree that the risk/reward trade-off looks unfavorable.

Fool contributor Brian Pacampara has no position in any stocks mentioned, and neither does The Motley Fool. 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.