U.S. foreclosure activity in July rose 55 percent from a year earlier as a slump in once-sizzling housing markets forced yet more borrowers to default on their mortgages, according to a monthly report.

Foreclosure filings — default notices, auction sale notices and bank repossessions — rose 8 percent from June and 55 percent from July 2007 to 272,171, according to RealtyTrac, which records property in various stages of foreclosure.

That means one in every 464 U.S. households received a foreclosure filing in July, the firm said. Bank repossessions (REOs) rose 184 percent year-over-year. Default notices were up 53 percent, and auction notices rose 11 percent.

"The sharp rise in REOs, combined with slow sales, has resulted in a bloated inventory of bank-owned properties for sale," James Saccacio, chief executive of Irvine, California-based RealtyTrac, said in a statement.

RealtyTrac now has more than 750,000 properties in its active REO database, or about 17 percent of the inventory of existing homes for sale reported in June by the National Association of Realtors, RealtyTrac said.

Among 230 metro areas tracked, Cape Coral-Fort Myers, Florida, registered the highest foreclosure rate. One in every 64 households there received a foreclosure filing last month, more than seven times the national average.

By state, Nevada led the country with its foreclosure rate in July, as one in every 106 households received a foreclosure filing. Foreclosure activity in Nevada rose 15 percent from the previous month and 97 percent from July 2007, RealtyTrac said.

REOs in Nevada jumped 384 percent from a year ago, default notices surged 59 percent and auction notices rose 31 percent.

In California, one in every 182 properties received a foreclosure filing. Florida was third, with one in every 186, while Arizona's rate was one in every 195 properties.

Other states with foreclosure rates among the top 10 were Ohio, Georgia, Michigan, Colorado, Utah and Virginia.

California was first by number of foreclosures with 72,285 in July, up 5 percent from June and 85 percent on a year ago. REOs in California rose 427 percent from a year ago, while auction notices rose 67 percent and default notices were up 34 percent. But default notices declined 4 percent from June.

Foreclosures in Florida rose 14 percent from June and 139 percent from a year earlier to claim the second highest number of properties, at 45,884. REOs rose 678 percent, auction notices were up 180 percent, and default notices doubled.

Ohio was third with 13,457 filings, up 2 percent from June and 1 percent from July 2007. Texas, Georgia, Nevada, Illinois and New York also were in the top 10 for foreclosure filings.