The FDIC, a U.S. bank regulator, has sued three large U.S. banks to recoup some of the more than $695 million it lost from selling shoddy residential mortgage-backed securities once owned by a Texas bank that failed in 2009.

Lawsuits stemming from the FDIC’s role as receiver for Austin-based Guaranty Bank, which had bought more than $2.7 billion of the securities, were filed against Citigroup Inc., Bank of New York Mellon Corp. and US Bancorp late Wednesday in Manhattan federal court.

The FDIC, whose full name is Federal Deposit Insurance Corp, said the banks failed in their role as bond trustees to ensure that mortgages backing Guaranty’s securities were properly underwritten, or to require lenders to fix or buy back troubled loans.

According to the lawsuits, the securities were issued from 2005 to 2007 and sponsored by the EMC unit of Bear Stearns Cos, now owned by JPMorgan Chase & Co,. or Countrywide Home Loans, now owned by Bank of America Corp.

In the Citigroup lawsuit, the last to be filed, the FDIC said it lost more than $200 million when it sold $420 million of Guaranty’s securities in March 2010.

The FDIC also reported more than $440 million of losses from selling $2.06 billion of securities overseen by Bank of New York Mellon, and more than $55 million of losses on more than $248 million of securities in the US Bancorp case.

Spokespeople for Citigroup and US Bancorp declined to comment. Bank of New York Mellon had no immediate comment. FDIC spokesman David Barr declined to comment.

Since 2013, the FDIC has reached $1.83 billion of settlements over mortgage securities sold to banks it took into receivership.

Guaranty Bank had roughly $13 billion of assets and $12 billion of deposits before its August 2009 demise. At the time, the FDIC estimated that the bank’s closure would cost its deposit insurance fund $3 billion.

The cases are in the U.S. District Court, Southern District of New York. They are Federal Deposit Insurance Corp v. The Bank of New York Mellon, No. 15-06560; Federal Deposit Insurance Corp v U.S. Bank NA, No. 15-06570; and Federal Deposit Insurance Corp v. Citibank NA, No. 15-06574.

(Reporting by Jonathan Stempel and Joseph Ax in New York; Editing by Frances Kerry)