New York's attorney general has requested data from 20 institutional investors that agreed to a $8.5 billion settlement with Bank of America Corp over their holdings in soured mortgage-backed securities.

In letters dated July 7 to the firms, the office of Attorney General Eric Schneiderman requested the names of various clients who invested in securities issued by the 530 Countrywide trusts covered in the settlement. It also sought the par and current market values of the clients' securities.

Schneiderman requested that the information be provided by July 14. Reuters obtained copies of the letters on Tuesday.

The settlement was intended to address much of Bank of America's remaining legal liability from its 2008 purchase of Countrywide Financial Corp, once the nation's largest mortgage lender. But it has drawn challenges from some Countrywide mortgage securities investors who question whether the settlement is fair.

Among the investors to settle with Bank of America were BlackRock Inc , MetLife Inc and Allianz SE's Pacific Investment Management Co.

(Reporting by Jonathan Stempel, editing by Bernard Orr)