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 Corning (NYSE:GLW) slipped as low as 2% on Friday after Piper Jaffray downgraded the specialty glass company from overweight, to neutral.

So what: Along with the downgrade, analyst Jagadish Iyer lowered his price target on the stock from $19 to approximately where it sits now, suggesting that he sees Corning's risk/reward trade-off as rather unattractive. While bargain hunters might be attracted to the stock's recent slide, Iyer cautioned that Corning could actually be a value trap given the numerous headwinds it faces.

Now what: Piper Jaffray thinks Corning shares will be pressured for several reasons:

  1. No meaningful display product cycle ahead, which in turn tempers glass volume consumption.
  2. Near term excess panel supply in front of slowing demand, particularly in China, is causing inventory to rise through the remainder of '13 and into early '14, thereby putting a downward bias on glass pricing.
  3. Stagnating display segment earnings over the next two years ($0.70-$0.80 /yr) suggests the stock could remain a value trap.

With Corning shares trading at a cheapish forward P/E of 10, and sporting a dividend yield of nearly 3%, however, it's hard to believe that those risks aren't already baked somewhat into the price.

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool recommends Corning. The Motley Fool owns shares of Corning. 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.