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 PMI Group (NYSE: PMI) jumped more than 10% in intraday trading on big volume.

So what: Shares of big banks such as Bank of America (NYSE: BAC) and Citigroup (NYSE: C) came under fire today as state attorneys general from around the country are turning a keen eye toward missteps the banks made in evicting delinquent borrowers. In the shadow of all of this is a glimmer of hope for mortgage insurers like PMI -- namely, that they will be able to put some of their losses back on the banks.

Now what: The entire mortgage insurance industry has been steamrolled by the housing collapse. However, as I noted earlier in the week, some big-time investors have started to jump on shares of PMI and others like MGIC Investment (NYSE: MTG). If the insurers are able to recover some of their losses from the banks, it would undoubtedly be a big positive, but it's unlikely that banks will just roll over and allow that to happen. PMI is still in a pretty precarious position, so investors looking at PMI should have a very clear understanding of exactly what they're getting into before they take the plunge.

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