The nationwide housing inventory took a slight dip last month despite the plentiful supply of bank foreclosure property.

The number of foreclosure homes for sale declined by almost 3.9 percent in May compared to figures a month earlier, according to ZipRealty Inc., an Emeryville, California-based real estate brokerage firm. The ZipRealty figures cover all condominiums, town houses and single-family homes in 28 major metropolitan cities.

Meanwhile, the National Association of Realtors data showed that the May housing inventory in 28 major metropolitan cities dropped by almost 24 percent, compared with the same month the previous year.

The association said that an estimated 4 million houses were placed on the sale list in April, representing a decline of 11 percent from the same month a year earlier.

Despite the decline in housing inventory, supply of bank owned foreclosure property remains plentiful on the national basis because the figures provided by both Zip and Realtors excluded all repo properties that banks have not yet placed on lists for sale.

Research firm Zelman and Associates noted that historically, inventories on the national level showed little change from April to May.

Meanwhile, housing economist Thomas Lawler said that the drop in home inventories across the country and the lack of activity in the housing construction market may indicate a slow drop in home prices too.

According to the Integrated Asset Services LLC’s U.S. house price index, April data was unchanged compared with a month earlier but dropped by 13 percent from a year-earlier period.

Meanwhile, in New York City, appraisal firm Miller Samuel Inc. reported that about 9,551 condominiums and cooperative apartments are listed for sale in May. The figures indicated an 8 percent drop from April but a 9 percent rise from the May 2008 total.

On the other hand, RealtyTrac’s May 2009 U.S. Foreclosure Market Report showed that 321,480 properties across the country were in danger of becoming bank foreclosure property. The figures represented a 6 percent decline from the April data but an 18 percent increase from a year-ago month.

Foreclosure filings were received by one out of 298 homeowners in the country. Furthermore, the number of bank foreclosure property inched up by 2 percent due to significant increases in several states, including Arizona, Washington, Oregon, Nevada, Michigan and New York.