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 engineering and construction specialist McDermott International (NYSE: MDR) plummeted more than 30% on Thursday after the company took a hatchet to its third-quarter profit outlook.

So what: McDermott's cut was so brutal -- it now sees third-quarter EPS of $0.03-$0.05 versus the consensus of $0.29 -- that Mr. Market is being forced to take the shares to a new two-year low. Revenues have been relatively solid, but spiking expenses and big writedowns -- the forecast includes roughly $50 million of project losses -- continue to weigh heavily on margins, not to mention investor patience.

Now what: I'd look into this plunge as a possible entry point. While the short-term outlook is obviously disappointing, CEO Stephen Johnson reassured investors that the third-quarter results "are not indicative of our outlook for the future." Management is expected to say those kinds of things, of course, but given the company's cash-rich balance sheet and the solid overseas growth it's been seeing, Johnson has decent reason to be positive about the long-term.    

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