A total of 446,726 homes nationwide were targeted by some sort of foreclosure activity from July to September, up 100.1% from 223,233 properties in the year-ago period, according to RealtyTrac.
The current figure was 33.9% higher than the 333,731 properties in foreclosure in the second quarter.
There was one foreclosure filing for every 196 households in the nation during the most recent quarter, RealtyTrac said.
In all, 635,159 filings were reported in the third quarter, up 99.5% from the year-ago quarter and up 30% from the second quarter of this year.
"Given the number of loans due to reset through the middle of 2008, and the continuing weakness in home sales, we would expect foreclosure activity to remain high and even increase over the next year in many markets," RealtyTrac CEO James Saccacio said.
Mortgage lenders are bracing for a flood of defaults as many adjustable-rate mortgages originated in 2005 and 2006 during the height of the housing market frenzy reset to higher interest rates.