The New York attorney general and MBIA are asking the state Court of Appeals to affirm a ruling dismissing a $5 billion fraud suit brought by a group of investment banks over the 2009 breakup of bond insurer MBIA.

The office of Attorney General Eric T. Schneiderman filed its brief Thursday in ABN Amro Bank NV v. MBIA Inc., 601475/09, on behalf of the state superintendent of insurance, who is the target of a separate Article 78 proceeding in Supreme Court challenging the superintendent’s approval of the breakup of MBIA, ABN Amro Bank NV v. Dinallo, 601846/09. The superintendent who approved the transaction, Eric Dinallo, is now a partner at Debevoise & Plimpton. He was replaced by James J. Wrynn in August 2009.