Renewed purchasing activity from the homebuyer federal tax credit hasn’t been enough to push home prices into positive territory, according to Denver, Colorado’s Integrated Asset Services, LLC (IAS). The default management and residential valuations company said Tuesday that home prices nationally fell 0.5 percent in October, compared to the previous month.

“I have no doubt that the tax credit persuaded some buyers to make their purchase sooner than they otherwise would have,” said Dave McCarthy, president and CEO of Integrated Asset Services. “It’s reasonable to think the broader market will reflect that reality at some point down the road.”

The drop in October follows a 0.6 percent reduction in the month-to-month numbers recorded for September. Based on the IAS360 House Price Index (HPI) – which includes non-conforming, REO, and conventional sales transactions, in addition to those insured by government agencies – home values nationally in October were down 6.2 percent from one year earlier.

IAS’ housing benchmark has fallen by more than 25 percent since its peak in July of 2006, and is roughly back to its January 2004 level.

McCarthy warns that the home-price slide could continue as rising unemployment causes more Americans to fall behind on their mortgage payments and end up in foreclosure.

“There is potential for another wave of inventory next year, both from private sellers and banks,” McCarthy said. “The risk of renewed home price declines remains significant.”

On a regional basis for the month of October, the IAS360 HPI shows that prices in the Northeast census region slipped another 1.6 percent in October, in no small part due to an outsized decline in the Boston commuting region, which includes Essex, Middlesex, Norfolk, Suffolk, and Plymouth counties. The Midwest also lost ground for the month, slipping 0.3 percent.

The Southern and Western parts of the country, though, actually recorded increases in home prices. The South, despite the continued woes of Florida’s hardest-hit neighborhoods, jumped 1.1 percent in October, IAS said. The West gained 0.5 percent, mostly the result of positive trends in California.

IAS signaled in its last monthly report that residential values in some of low-priced California and Florida markets were on the rise, and that assessment appears to be playing out still.