UBS has asked the U.S. Court of Appeals in Manhattan to overturn a ruling that allowed the Federal Housing Finance Agency to proceed with its suit against the lender in an effort to recover billions in losses from mortgage bonds sold to Fannie Mae and Freddie Mac, Bloomberg Businessweek reported Nov. 26.

Arguing that the FHFA missed the timeframe for filing claims, UBS is hoping to end the federal lawsuit over $6.4 billion in mortgage bonds. If the lawsuit is defeated, the ruling could damage future efforts to recover losses that Fannie and Freddie suffered during the housing crisis.

Dan Flanigan, chairman of the financial services and real estate practices at law firm Polsinelli Shughart PC, told Bloomberg Businessweek that UBS might be fighting a hopeless battle, saying that “there is huge political pressure not to let these banks off the hook.”

UBS is not the only bank being sued by the FHFA. JPMorgan Chase, Barclays and Goldman Sachs also are facing suits

Attorneys for UBS have argued that if the court allowed these cases to proceed, it would expose the banks to federal and state securities law claims “long after Congress and the relevant state legislatures determined that such claims should have expired.” The FHFA sued UBS in July 2011, and then followed that suit with suits against 17 other firms in September 2011.

According to Bloomberg Businessweek, the FHFA has argued that loans backing securities sold to Fannie and Freddie were riskier than represented. The original amount of these mortgage-backed securities is about $200 billion.

UBS argued that the timeframe for making such claims expired in 2010 and are barred by the “statute of repose.” In its recently filed brief, UBS attorneys wrote, “This appeal involves a belated attempt by the two largest and most sophisticated issuers and purchasers of MBS in the world to shift blame for losses they suffered as a result of the nationwide housing crisis in which they played a critical role,” Bloomberg Businessweek reported.

A federal judge in May initially rejected UBS’ argument, ruling that the act that established the FHFA in 2008 gave the agency three years from the date it took Fannie and Freddie under conservatorship to bring securities law claims.

The FHFA has argued that it would be nearly impossible for the agency to recover losses if subject to time restrictions and that blocking it from pursuing claims against banks like UBS “would defeat the very purpose” of the 2008 law establishing the agency.

Legal observers think the matter likely will be appealed to the U.S. Supreme Court, Bloomberg Businessweek reported.