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 mortgage insurer MGIC Investment (NYSE: MTG) sank 17% in afternoon trading Wednesday, as its May operating statistics failed to impress investors.

So what: While MGIC managed to report a 1.5% drop in loan delinquencies and $1 billion in new insurance written, the results just weren't as strong as Mr. Market had hoped. In fact, the shares are hitting new 52-week lows on the monthly report and are now down more than 40% year-to-date.

Now what: Although MGIC's recent delinquency rates seemed to have been moving in the right direction, today's report suggests that the trend may be losing steam. Foreclosures lag mortgage delinquencies, after all, so it's difficult to tell exactly how long the housing crisis will continue to plague MGIC, as well as fellow mortgage insurers PMI (NYSE: PMI) and Radian (NYSE: RDN) (also down big today). In other words, I'd continue to keep my distance for now.

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Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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