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: Shares of diversified manufacturer Ingersoll Rand (NYSE: IR) plunged 17% in early trading today after lowering its full-year outlook.

So what: The guidance cut was so big -- management now expects per-share operating earnings of $0.77-$0.80 versus its prior view of $0.85-$0.95 per share -- that it's hard to blame Mr. Market for wanting to heavily discount the stock. In fact, Ingersoll shares are hitting their lowest level in more than two years on this news.

Now what: Expect more short-term pain for the entire space. Ingersoll's downside guidance doesn't exactly bode well for manufacturing gorillas like General Electric (NYSE: GE) and 3M (NYSE: MMM), which a few analysts expect to issue profit warnings of their own pretty soon. Of course, for investors searching for cheap blue chips to hold over the long term, the industrial sector seems like a good place to start.

Interested in more info on Ingersoll? Add it to your watchlist.

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.