MBIA Insurance is suing Countrywide Financial, alleging that the mortgage lender fraudulently induced MBIA to guarantee billions of dollars of Countrywide mortgage bonds that have cost the embattled bond insurer more than $459m.

The suit, filed in New York state's supreme court, raises fresh questions over the extent of Bank of America's exposure to potential legal and regulatory liabilities incurred by Countrywide, which it acquired this year.