In this series, we take a look at the 25 stocks on the S&P 500 Index (SPX) that have turned in the worst performance during the past decade -- what went wrong, and what happens next. (See all 25).

While financial-services firms have been dragged down as a group for more than a year, few have flamed out with the spectacular ferocity of municipal bond insurer MBIA Inc. (NYSE: MBI). In fact, among equities listed on the S&P 500 during the past decade, only one stock has suffered a more severe plunge in share price.

What went wrong? At no. 2 on our list of SPX slackers, MBI lost 91% of its value during the decade that ended June 30, 2008. The stock peaked at $76.02 in January 2007, which marked the last in a series of higher highs for the formerly uptrending security.

MBIA's troubles first started in January 2007, though its issues at the time would pale in comparison with later challenges. Then, the company agreed to pay $75 million to settle civil securities-fraud charges by federal and New York State authorities. MBIA was accused of making secret side deals with reinsurance companies to avoid stating a $170-million loss in 1998. As part of the settlement, MBIA said it would restate earnings from 1998 through 2004 and improve its business and accounting procedures.