Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: As the rest of the stock market roared north to the tune of 2.3% (for the Nasdaq) and 1.2% (for the Dow Jones Industrials (INDEX: ^DJI)) today, shares of specialty chemicals producer Ferro (NYSE: FOE) eked out a mere $0.01 gain.

So what: Bad news? Hardly. Earlier in the day, Ferro shares were down as much as 10%, crushed by an early morning downgrade from KeyBanc Capital Markets. Like peers Kraton Performance Polymers (NYSE: KRA), Quaker Chemical (NYSE: KWR), Omnova Solutions (NYSE: OMN), and PolyOne (NYSE: POL), Ferro got cut from "buy" to "hold" by KeyBanc. Worse news still: According to our CAPS stats, KeyBanc isn't often wrong about these things -- the analyst ranks in the top 10% of investors we track.

Now what: Sure, Ferro shares don't look all that unreasonably priced, selling for less than 13 times trailing earnings, and pegged to 13% long-term growth. But investors who rushed back into the stock after the morning's downgrade, beware: KeyBanc warns that no matter how cheap Ferro looks, "cheapness has been redefined on a weekly basis" in today's markets. At a price today that looks no better than fair, and could even be worse when you consider how heavily indebted Ferro is, I wouldn't be too quick to dismiss KeyBanc's concerns.

Disagree? Think the banker is blowing this out of proportion? Add Ferro to your Fool Watchlist and see if you're right.