John Morton, a newspaper consultant based in Maryland, said that Newsday's circulation scandal is the biggest he has come across in the 30 years he has studied the industry.

Sue Kaplan of Merrick said she had somehow managed to miss the news about the circulation scandal.

But Mr. Bellavia said his clients felt that the circulation scandal added insult to injury.

The company has had double-digit advertising losses at Newsday, after a circulation scandal at the paper, and it sold two television stations in Atlanta and Albany during the quarter.

"If I'm a chief executive of a public newspaper company, my window of opportunity to announce a circulation scandal has pretty much closed," he said.

And over the last several years, The Post and The News have carried stories raising questions about the validity of one another's sales figures, amid circulation scandals at papers elsewhere.

The filing of the lawsuit by the car dealers represents the latest chapter in a circulation scandal that began in February.

It also comes as Hollinger International finds itself embroiled in a circulation scandal at its biggest American newspaper, The Chicago Sun-Times.

The paper has been in turmoil since mid-2004, when it was embroiled in a circulation scandal that prosecutors say cheated advertisers out of millions of dollars.

With the sales, the company, troubled by a two-year-old circulation scandal, is effectively rid of its American magazines, although it retains ownership of a magazine printing company.