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 finance insurance provider MBIA (NYSE: MBI) hit a big payout today, jumping as high as 12.6% on moderately heavy trading.

So what: MBIA shareholders can thank Bank of America (NYSE: BAC) for this pop, because the giant bank struggling out of $8.5 billion of bad debt today is the force behind it. That drastic move significantly reduced MBIA's insurance risk on many of the assets involved. The event also pushed up rivals Assured Guaranty (NYSE: AGO) and Radian Group (NYSE: RDN) to a smaller degree.

Now what: This doesn't necessarily make MBIA a great buy today. The stock has actually only gained 4% since Monday night, for the New York Court of Appeals revived a stalled lawsuit by a consortium of 11 banks against the company -- including today's savior, Bank of America. MBIA could still be on the hook for truly massive damages, both in court and in the regular course of business, making it easy to see why the stock rates a single, lonely star (out of five) in our CAPS system.

Interested in more info on MBIA? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. The Fool owns shares of, and has opened a short position on, Bank of America. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.