RealtyTrac, an online marketplace for foreclosure properties, says foreclosure notices were filed on 333,837 properties in April - down nine percent decrease from March and a drop of two percent from the same month a year ago. One in every 387 U.S. housing units received a foreclosure filing during the month.

"There were two important milestones in the April numbers that show foreclosure activity has begun to plateau -- but at a very high level that will not drop off in the near future," said James J. Saccacio, chief executive officer of RealtyTrac. "April was the first month in the history of our report with an annual decrease in U.S. foreclosure activity. Secondly, bank repossessions, or REOs, hit a record monthly high for the report even while default notices dropped substantially on a monthly and annual basis."

Saccacio says he expects a similar pattern to continue for most of this year, with the overall numbers staying at a high level. He also looks for "ripples of activity" hitting the various stages of the foreclosure process as lenders work through the backlog of distressed properties.

During April a total of 103,762 properties received default notices (NOD, LIS), a decrease of 12 percent from the previous month and a decrease of 27 percent from April 2009 -- when default activity peaked at more than 142,000.

Foreclosure auctions (NTS, NFS) were scheduled for the first time on a total of 137,643 properties during the month, a decrease of 13 percent from the previous month -- when auction activity peaked with more than 158,000 properties scheduled for auction for the first time. Auction activity was up one percent from April 2009.

Bank repossessions (REOs) hit a record monthly high for the report in April, with a total of 92,432 properties repossessed by lenders during the month -- an increase of one percent from the previous month and up 45 percent from April 2009. Bank repossessions were less than one percent above their previous peak of 92,182 in December 2009.

Nevada posted the nation's highest state foreclosure rate for the 40th straight month, with one in every 69 housing units receiving a foreclosure filing in April -- more than five times the national average.

Arizona foreclosure activity decreased nearly 15 percent from the previous month, but the state's foreclosure rate moved from third highest in March to second highest in April thanks to an even bigger decrease in California.

Florida posted the nation's third highest foreclosure rate, with one in every 182 properties receiving a foreclosure filing, despite monthly and annual decreases in foreclosure activity.

California posted the nation's fourth highest foreclosure rate, with one in every 192 housing units receiving a foreclosure filing, and Utah posted the nation's fifth highest foreclosure rate, with one in every 221 housing units receiving a foreclosure filing.

Other states with foreclosure rates ranking among the top 10 in April were Idaho, Michigan, Illinois, Georgia and Colorado.

Other highlights in RealtyTrac's U.S. Foreclosure Market Report for April 2010 include:

• California, Florida, Michigan, Illinois and Nevada accounted for 52 percent of the national total. California led the way, with 69,725 properties receiving a foreclosure filing -- although that total was down 25 percent from the previous month and down nearly 28 percent from April 2009.

• Florida foreclosure activity was down 18 percent from the previous month and down 25 from April 2009, but the state still documented the nation's second highest state foreclosure activity total, with 48,384 properties receiving a foreclosure filing during the month.

• An eight percent month-over-month increase in foreclosure activity boosted Michigan's total to third highest among the states in April. A total of 19,173 Michigan properties received a foreclosure filing during the month, up 77 percent from April 2009.

• Illinois foreclosure activity increased nearly 33 percent from the previous month, the nation's seventh biggest month-to-month increase, and the state's 18,870 properties receiving a foreclosure filing was the fourth highest total among all states.

• A total of 16,217 Nevada properties received a foreclosure filing in April, the fifth highest total among the states.

• Other states with foreclosure activity totals among the nation's 10 highest were Arizona (16,088), Georgia (13,963), Texas (13,133), Ohio (11,936), and Virginia (7,065).