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
So what: The spike in PMI shares -- along with shares of fellow mortgage insurer Radian Group
Now what: Since there doesn't seem to be a solid reason for either of these stocks -- PMI or Radian -- to be gaining today, I'd be tempted to say that the gains won't hold. But that probably puts too much faith in the efficiency of the markets. The one thing that I can say for sure is that these have been particularly volatile stocks, and they will continue to be volatile as the companies work through the tough housing market and try to regain a solid footing.