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 QUALCOMM (NASDAQ:QCOM) slipped 1% in premarket trading Friday after Goldman Sachs downgraded the mobile chipset giant from Conviction Buy to Buy.

So what: Along with the downgrade, analyst Simona Jankowski reiterated her price target of $95 on the stock, representing about 18% worth of upside to yesterday's close. So while momentum traders might be attracted to QUALCOMM's price strength over the past year, Jankowski's call could reflect a sense on Wall Street that its valuation is becoming a bit stretched.

Now what: Goldman trimmed its June and September quarter outlook for QUALCOMM to reflect weaker near-term handset demand. "We are removing Qualcomm from the Americas Conviction List (CL), as the catalysts laid out in our November 12, 2013, note have largely played out (more aggressive capital allocation, chipset margin expansion, 'stronger for longer' chipset segment, and resilient royalty ASPs)," said Jankowski. "Looking out from here, we do not expect material upside to consensus estimates in the intermediate term and may even see some near-term downside. However, we maintain our Buy rating, as in our view the stock is undervalued relative to its growth and returns profile." Given Goldman's still-upbeat view on QUALCOMM's long-term prospects, patient shareholders might want to take that short-term bearishness with a grain of salt. 

Brian Pacampara has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple and Qualcomm. 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.