Marvin L. Stone, the editor of U.S. News & World Report for the past nine years, announced his resignation yesterday, three months after the magazine was acquired by Boston real estate magnate Mortimer B. Zuckerman.

In a staff meeting, Stone said he plans to leave the magazine some time this spring. He said he had received several job offers outside the publishing industry, some of which may be made public later this week.

Zuckerman accepted Stone's resignation with "great regret" and said no successor had yet been named. Stone will continue to oversee the magazine's daily operations until he leaves.

Sources close to the magazine dismissed rumors circulating among its staff that Stone might be named ambassador to West Germany or the United Nations.

"I will be celebrating my 25th anniversary with the magazine and my 40th year in journalism and it's time I had a change." said Stone, 60, in a statement released to the press later in the day.

Ever since it was announced last summer that Zuckerman would buy the magazine for $176.3 million, the staff had expected Stone to leave some time around the first of the year.

Stone himself even signaled this possibility in an interview with The Washington Post last summer, shortly after the company announced that it would sell all its assets to Zuckerman. He said he agreed with Zuckerman to stay on in his post, but "nothing lasts forever."

Although no successor has been named, staff speculation centered immediately on either Harold Evans, editorial director, and James K. Glassman, executive vice president. Zuckerman brought both into the magazine after he acquired it.

In his nine-year tenure as editor, Stone has been credited with spicing up the 50-year-old magazine that was founded by David Lawrence, adding color photos and stories about social issues and trends to the magazine's traditional political and international menu of stories.

"In his distinguished editorship and his long service with the magazine, Marvin has performed an extraordinary service to journalism and to the U.S.," Zuckerman said.

Stone said he expected Zuckerman will continue to improve the quality of U.S. News. "Everything I have had to do with Mr. Zuckerman since his acquisition last October has reinforced my conviction that the editorial integrity and direction of the magazine will continue on the path it has held to for the last half-century," he said.