New York Attorney General Andrew Cuomo says he'll file suit against Merrill Lynch & Co. over its role in selling auction-rate securities if the investment bank doesn't reach an agreement with his office by the end of the day.

Cuomo, in an interview with The Associated Press, said talks with the nation's biggest brokerage are at an impasse. He said the suit would be filed Friday.

A spokesman for Merrill Lynch declined to comment.

Five major banks including Citigroup Inc. and Switzerland's UBS AG have agreed to $42 billion in settlements with Cuomo and other regulators that require the companies to buy back the securities. The investigations concern how brokerages sold auction-rate securities before the $330 billion market collapsed in February.