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) jumped more than 10% in intraday trading, as the company reported better-than-expected third-quarter earnings.

So What: Thanks the wave of mortgage defaults washing over the U.S., mortgage insurers such as MGIC have been chalking up huge losses. After reporting a surprise profit last quarter, the company was back in the red this quarter, but its $0.26 per-share loss was not only much better than the $4.17 drubbing a year ago, but also better than the $0.67 loss that analysts expected.

Now What: Shares of the mortgage insurers have been bouncing all over the place lately, most notably thanks to the foreclosure debacle now plaguing banks like Bank of America (NYSE: BAC) and Citigroup (NYSE: C). Shares of MGIC, along with other insurers like Ambac (NYSE: ABK) and PMI Group (NYSE: PMI) were hopping last week, as investors hoped that the foreclosure mess would mean more room for the insurers to put losses back onto the banks. While it's possible that could provide some relief for the group, the real path back to sustainability will depend on tighter underwriting standards -- and getting the rest of the bubble-era junk flushed off the balance sheets.

Interested in more info on MGIC Investment? Add it to your watchlist here by clicking here.

Try any of our Foolish newsletter services free for 30 days. True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community.

Fool contributor Matt Koppenheffer does not own shares of any of the 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 on his RSS feed. The Fool’s disclosure policy assures you no Wookiees were harmed in the making of this article.