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.

Fool contributor Rich Smith does not own (or short) shares of any company named above. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.