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 Ion Geophysical Corp (NYSE:IO) sank 6% on Wednesday after Barclays downgraded the geophysical technology company from overweight to equalweight.

So what: Along with the downgrade, analyst James West lowered his price target to $4 from $5, representing about 7% worth of downside to yesterday's close. So while momentum traders might be attracted to the stock's sharp bounce in recent months, West's call suggests growing sentiment on Wall Street that investors have gotten ahead of themselves. 

Now what: According to Barclays, Ion's risk/reward trade-off is pretty balanced at this point. According to West:

Seismic spending is expected to grow in the low single digits this year, well below our expectations for worldwide E&P spending growth of around 6%. We continue to believe IO is well positioned for exploration in various frontier basins, notably the Arctic, as well as a recovery in seismic activity once exploration sentiment improves. However, at this time we see better value elsewhere in our coverage universe (including the large diversified service companies and SMID cap NAM players).

When you couple that bearish outlook with Ion's still-hefty debt load and highly volatile shares, it's tough to disagree with Barclays' cautious stance. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.