NEW YORK — At a time when people don't want to wait a minute for information, let alone seven days, do newsweeklies have a future? If Newsweek does, it won't be with its current owner.

The 77-year-old magazine, hobbled by sagging ad revenue and circulation, is being put up for sale by The Washington Post Co., which is bowing out of the struggle to keep the genre relevant.

The recession and online competition have left magazines and newspapers in general struggling to hang on to advertising revenue and circulation, but newsweeklies such as Newsweek, Time and U.S. News & World Report have a particular challenge finding a niche. Once useful digests of the week's events, news-weeklies now have to compete for attention with up-to-the-second online news and commentary from all quarters.

"It's very difficult to sustain a newsweekly when you have instantaneous news," said Roland DeSilva of DeSilva and Phillips, an investment bank focused on the media industry. He said Newsweek's redesign last year "was doomed to fail simply because there's no need — there's no reader need."

Newsweek has been piling up losses for the past two years. It cut costs through voluntary buyouts that have reduced its staff by about a quarter; it ended 2009 with 427 employees. And it tried to better compete with more upscale magazines such as The Economist and The New Yorker with a complete redesign of its print and online editions last year.

Neither step has done enough. The Post Co. said yesterday it has retained the investment bank Allen & Co. to help find a buyer for the magazine.

"Newsweek's staff has been remarkable in cutting expenses and putting out a great magazine," Post Co. Chairman Donald E. Graham said in an interview. "But we did not see a path to sustained profitability within the company."

Jon Meacham, the magazine's editor, said he is exploring every option for keeping Newsweek afloat, even the possibility of forming a group of backers to take it over.

"We have so few common denominators and I don't think the country would benefit from having one less," he said.

While the Post Co. says it has no deadline for a sale, the company would not comment on what would happen if no buyer steps up.

The Graham family, which has controlled the Post since Katharine Graham's father bought the newspaper in 1933, acquired Newsweek in 1961 with the idea of raising its stature to the level of its more august and wealthy competitor, Time.

Phil Graham, then the Post's publisher, "wanted desperately to make Newsweek big-time, and big-time as quickly as he could," wrote David Halberstam in his 1979 book, "The Powers That Be." To do it, Graham hired Walter Lippmann, among the most famous columnists of his generation.

In the years since, Newsweek has won a dozen National Magazine Awards, the industry's top honor, compared with Time's 10. It took home this year's award for commentary with three columns by Fareed Zakaria.

While circulation for the magazine's domestic edition was more than 3 million through the 1990s, it declined to 2.3 million last year. And for this year, Newsweek is promising advertisers a circulation of just 1.5 million. It is difficult, though, to pin down exactly how the magazine's readership has held up; Newsweek says it has voluntarily reduced the numbers to cut down on what it considered unprofitable circulation.

For the Post Co., unloading Newsweek's losses could be about circling the wagons around its namesake property.

"The Washington Post is the real flagship and it's very important to the Graham family," said Rick Edmonds, a media business analyst at the nonprofit Poynter Institute. "If they're not finding enough resources available to develop the Post, Newsweek becomes expendable."