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 Genworth Financial (NYSE: GNW) went splat today, falling as much as 20% in intraday trading on heavy volume.

So what: News flash: The housing and financial meltdown is still doling out hefty helpings of pain. If you have trouble believing that, look no further than Genworth's expected second-quarter results. For the quarter, the company expects to report a loss of $92 million to $112 million, or $0.19 to $0.23 per share. The loss was driven by a $300 million reserves build in the company's U.S. mortgage insurance unit as the company saw "worsening trends" in the U.S. housing market.

Now what: If misery loves company, then it should really love the mortgage-insurance space today. Though the rest of the market was up, the news from Genworth helped drag down fellow insurers MGIC Investment (NYSE: MTG), Radian (NYSE: RDN), and PMI Group (NYSE: PMI) as investors digested what those "worsening trends" might mean for the rest of the group.

It seems the only cure for this ugliness may be time and the digestion of the sins committed during the housing bubble. As such, the key for Genworth and its fellow mortgage insurers will be keeping capital levels in safe-enough ranges that they don't run into regulatory problems.

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Fool contributor Matt Koppenheffer owns shares of Genworth, but does not have a financial interest in any of the other companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or Facebook. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.