A federal judge has dismissed nearly all of a lawsuit against Bank of America Corp (BAC.N) and US Bancorp (USB.N) that held them liable for losses on roughly $6.8 billion in toxic mortgage securities that helped sink five federal credit unions.

In a decision made public early Friday morning, U.S. District Judge Katherine Forrest in Manhattan rejected claims by the National Credit Union Administration (NCUA) that the banks failed in their roles as trustees for 98 residential mortgage-backed securities trusts.

Forrest said the NCUA lacked standing to sue over 89 trusts because the right to sue had been previously assigned, leaving the regulator with only an interest in payment streams.

The judge also dismissed claims that the banks breached their fiduciary duties or acted in bad faith with the other nine trusts. The only surviving claims are those of breach of contract on the nine trusts, which the banks did not seek to dismiss.

NCUA spokesman John Fairbanks said the regulator is reviewing the decision.

Bank of America spokesman Lawrence Grayson and US Bancorp spokesman Dana Ripley declined to comment.

The lawsuit is one of many in which the NCUA has sought to recoup losses on mortgage securities bought before the financial crisis, and which led to the 2009 and 2010 failures of the Constitution Corporate, Members United Corporate, Southwest Corporate, U.S. Central and Western Corporate credit unions.

Some lawsuits targeted banks that allegedly sold securities backed by defective home mortgages. Other lawsuits targeted trustees that allegedly failed to monitor loan servicers or require banks to buy back defective loans.

The NCUA has recouped close to $2.46 billion through lawsuits it began filing in 2011, including $33 million this week with Switzerland's UBS AG UBSG.VX.

The case is National Credit Union Administration Board v. U.S. Bank NA et al, U.S. District Court, Southern District of New York, No. 14-09928.