New York ? The Tribune Co. — owner of the Los Angeles Times, Chicago Tribune, Baltimore Sun and other dailies — filed for Chapter 11 bankruptcy Monday, the first major newspaper publisher to take such a step since the Internet plunged the industry into a desperate struggle for survival.

The media conglomerate was smothered by a drop-off in advertising and a crushing $13 billion in debt from the company’s takeover a year ago by Chicago real estate mogul Sam Zell.

Chapter 11 would buy the Tribune Co. time to put its finances in order. Analysts said the company will almost certainly have to sell off some of its major holdings — and that could prove extremely difficult because of the bad economy and the poor outlook for newspapers.