WASHINGTON — The number of homeowners swept up in the housing crisis rose last month, with foreclosure filings up nearly 50 percent compared with a year earlier, a foreclosure listing company said Friday.

Nationwide, 261,255 homes received at least one foreclosure-related filing in May, up 48 percent, from 176,137, in the same month a year ago and up 7 percent from April, the listing company, RealtyTrac, said.

One in every 483 households received a foreclosure filing in May, the highest number since RealtyTrac started the report in 2005 and the second-consecutive monthly record.

Foreclosure filings increased from a year earlier in all but 10 states, with Arizona, California, Florida, Michigan and Nevada having the highest statewide foreclosure rates.

Metropolitan areas in California and Florida accounted for 9 of the top 10 areas with the highest rate of foreclosure. That list was led by Stockton, Calif., and the Cape Coral-Fort Myers area in Florida.

RealtyTrac monitors default notices, auction sale notices and bank repossessions. Nearly 74,000 properties were repossessed by lenders nationwide in May, while more than 58,000 received default notices, the company said.

In Nevada, one in every 118 households received a foreclosure-related notice last month, more than four times the national rate. In California, one in every 183 households faced foreclosure.

The combination of weak housing sales, falling home values, tighter mortgage lending criteria and a slowing economy has left distressed homeowners with few options to avoid foreclosure.

Rick Sharga, RealtyTrac’s vice president for marketing, said foreclosures were unlikely to peak until this fall, as more loans made to borrowers with poor credit records reset at higher levels. “I don’t think we’ve seen the high point,” he said.

About 50 to 60 percent of borrowers who receive foreclosure filings will probably lose their homes, Mr. Sharga said. The rest are likely to be able to sell or refinance.