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 ON Semiconductor Corp. (UNKNOWN:ONNN.DL) slipped 1.5% today after MKM Partners downgraded the chip company from "buy" to "neutral."

So what: Along with the downgrade, analyst Ian Ing lowered his price target to $8 (from $10), representing about 13% worth of upside to Friday's close. While value investors might be attracted to ON's share-price slide in recent months, Ing believes that the company's appreciation prospects remain limited given its exposure to strong global economic headwinds.

Now what: While MKM acknowledges that ON is nicely positioned for a recovery, it isn't seeing that recovery just yet. "Our thesis is that highly diversified and manufacturing-heavy ONNN is heavily dependent on a global macroeconomic recovery to drive semiconductor demand," noted MKM. "We look to turn more constructive should macroeconomic improvement and/or rationalized semiconductor supply place ONNN on a sustainable trajectory of improved GM/OM leverage." Of course, with ON shares now off about 20% from their 52-week highs and trading at a forward P/E of 10, now might be one of the best times to bet on that improvement.