Gannett Co. Inc., the largest U.S. newspaper company, is pursuing a bid for rival Tribune Co. , while Maurice Greenberg, the former chairman of the insurance giant American International Group, has also expressed interest in the company, according to media reports.

After putting in a bid for the whole company, Gannett executives visited Tribune's Chicago headquarters to hear management's presentations, the Chicago Tribune and Los Angeles Times -- both Tribune papers -- reported over the weekend. The Wall Street Journal also reported the meeting in its online edition on Sunday.

The New York Times reported on Monday that Greenberg too is considering a bid for Tribune and has been reaching out to investment bankers and lawyers about pursuing an offer.

Greenberg has also expressed interest in pursuing The Boston Globe, owned by the New York Times, and Dow Jones, publisher of the Wall Street Journal.

Gannett's pursuit of Tribune, publisher of USA Today, forms part of an already crowded field of suitors, which includes several groups of private equity firms.

Tribune, with a market value of about $8 billion, is trying to sell itself against the background of weak financial results, an uncertain future and pressure from the Chandler family, a major shareholder.

Tribune assets also include New York's Newsday and the Chicago Cubs baseball team.

Since opening the bidding process, Tribune has reached out to several media groups, including Gannett, Hearst Corp. and Dean Singleton's MediaNews Group Inc., the Wall Street Journal reported on Sunday, citing people familiar with the matter.

The company also has been in contact with News Corp., which is interested in Newsday in New York, the Journal said.

MediaNews has had informal discussions with Tribune about some of its assets, such as the Hartford Courant and the Stamford Advocate in Connecticut, but hasn't had any meetings with the company, the Journal said, citing one person familiar with the matter.

A Gannett spokeswoman declined to comment. Greenberg could not immediately be reached for comment.

Tribune recently posted lower-than-expected third-quarter revenue, joining other newspaper publishers in reporting weak advertising sales.

One preliminary offer was put in by a private equity group made up of Texas Pacific Group and Thomas H. Lee Partners, one source familiar with the situation has told Reuters.

Another offer was put in by a group consisting of Madison Dearborn Partners, Providence Equity Partners and Apollo Management, a separate source close to the situation has said.

Private equity group Bain Capital also put in a bid and the Carlyle Group has also looked at Tribune, sources have said.

BILLIONAIRES' BALL

Greenberg joins a list of other wealthy individuals expressing interest in the struggling newspaper industry.

Los Angeles billionaire philanthropist Eli Broad and fellow billionaire Ron Burkle have made a bid to buy newspaper publisher and broadcaster Tribune Co., a source close to the situation has previously told Reuters. (Please see the story at

).

The news of a bid by Broad and Burkle, a grocery store chain investor, came a day after Los Angeles Times editor Dean Baquet said he would leave the paper, which is one of Tribune's biggest properties, after Baquet lost a battle to resist job cuts.

(Additional reporting by Megan Davies and Robert MacMillan)