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 and retirement products provider Genworth Financial (NYSE: GNW) slid as much as 12% after the company reported disappointing fourth-quarter results.

So what: Well, the U.S. housing market still stinks and that pretty much sums up Genworth's ugly fourth-quarter report. Overall, the company reported a per-share loss of $0.33, which badly missed expectations of a $0.16 profit. Solid profits in the company's retirement products and international segments were easily swallowed by a hefty loss in its U.S. mortgage insurance business. The U.S. mortgage insurance loss was driven by pre-tax increase in loss reserves of $350 million.

Now what: The outlook for the U.S. mortgage insurance business isn't going to improve particularly quickly, and the head of that business unit said it won't return to profitability in 2011. Not surprisingly, other mortgage insurers including Radian Group (NYSE: RDN), PMI Group (NYSE: PMI), and MGIC Investment (NYSE: MTG) were all trading down today. Some investors have been looking ahead to the possibility of Genworth splitting its business in two to separate mortgage insurance from the retirement-products business, but management seems set on keeping the company together until results improve.

It's hard to get overly excited about a business under such a dark cloud, but Genworth's stock is currently trading at a mere fraction of its shareholders' equity, so for investors who don't mind ugly stocks, it may be worth a second look.

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