US banking regulators will carry out their own investigation into whether lenders were wrong to repossess hundreds of thousands of homes.
The Federal Reserve chairman, Ben Bernanke, says regulators will look at whether mortgage companies cut corners on their own procedures when they moved to foreclose on people's homes.
Attorneys General in all 50 US states are already looking into the issue.
Meanwhile, US existing home sales grew by 10% in September.
The National Association of Realtors said home sales rose to a seasonally adjusted annual rate of 4.53 million.
The annual rate has risen from July's rate of 3.84 million, which was the lowest in 15 years.
Since September 2005, home sales have fallen by 37.5% from their peak annual rate of 7.25 million.
It is feared sales could fall further if potential lawsuits from former homeowners, who are claiming banks made errors in seizing their homes, make potential buyers cautious about purchasing foreclosed properties.
"You're going to see uncertainty on the part of homebuyers," said Quinn Eddins, director of research at Radar Logic, which tracks the housing market.
The repossession investigation centres on whether shoddy paperwork was used for the evictions.
Mr Bernanke says preliminary results of the regulators' in-depth review are expected to be released next month.
It follows allegations that the companies often mishandled documents when people behind on their mortgages had their houses taken from them.
According to industry figures, more than 2.5 million US homes have been repossessed since December 2007.
A number of the US's biggest lenders have halted repossessions amid fears that some evictions were rushed through without the paperwork being read by bank employees.
Lenders including Bank of America and JP Morgan Chase have halted repossessions, although they have since restarted the process in certain states.
The Obama administration said last week it had found no sign so far of "systemic" home foreclosure troubles.
But the Housing and Urban Development Secretary, Shaun Donovan, said a four-month federal probe of big banks' mortgage practices had discovered "significant variation" in compliance with government rules, and has promised to force changes as needed.