CHICAGO – A breakup of Tribune Co. appears increasingly possible after the media conglomerate reportedly signaled its willingness to consider offers for its parts, telling private-equity firms their bids for the entire company were far too low.

However, tax complications involving individual transactions could jeopardize the company’s plan to decide on major restructuring actions by the end of the year.

Chief Executive Dennis FitzSimons has long insisted the company wanted to hang onto its core businesses, such as the Chicago Cubs and media holdings in Chicago, Los Angeles and New York. He insisted as recently as September, when Tribune put the whole company on the auction block, that the Los Angeles Times, its largest newspaper, wasn’t for sale.

But several published reports Thursday said Tribune representatives made a series of calls the previous day telling those who have expressed interest in the company’s individual holdings that they are now available for sale.

Tribune Co. spokesman Gary Weitman declined comment on the reports in The Wall Street Journal, the Chicago Tribune, the Los Angeles Times and The New York Times, which were based on unidentified sources.

Shares in the company fell 36 cents, or 1.1 percent, to close at $32.26 on the New York Stock Exchange.

Several analysts said lackluster bidding was to be expected at a time when Tribune’s print advertising revenue is sluggish, the circulation of its newspapers continues to decline and the industry wide outlook is cloudy.

“This is no surprise given (the) similar response to the Knight Ridder auction earlier this year, when we would argue that the newspaper ad market was not quite this bleak,” Bear Stearns analyst Alexei Quadrani wrote in a research note.

Like Knight Ridder Inc., the newspaper publisher that sold itself off earlier this year, Tribune is under pressure to boost a persistently lagging stock price that reflects its newspapers’ slump, as readers and advertisers migrate to the Internet. But it has not been able to find a single buyer, as Knight Ridder did with McClatchy Co.

So far, according to the Tribune, three investor groups have submitted preliminary, nonbinding bids for the company.

One group consists of Fort Worth-based Texas Pacific Group and Boston-based Thomas H. Lee Partners. The other bids came from Boston-based Bain Capital and an alliance made up of Chicago’s Madison Dearborn Partners, New York-based Apollo Management and Rhode Island-based Providence Equity Partners.

Investors have shown the strongest interest in the company’s individual units.

Billionaire Ron Burkle, business leader Eli Broad and Hollywood mogul David Geffen have voiced interest in the Los Angeles Times, but no formal offer is said to have been made.

Analyst Quadrani said she spoke to Tribune on Wednesday and, despite the reports that it will now accept offers for individual assets, the company has not decided whether to pursue such sales.

But numerous other industry experts think a major sale of at least part of the company remains almost inevitable.

“If they don’t do something, the shareholders will line up against them the way they did Knight Ridder, and come the next annual meeting they’ll be undermined with a very serious shareholder challenge just like (Knight Ridder CEO) Tony Ridder was,” said Benchmark Co. analyst Edward Atorino. “If they want to get the best value, they’re going to have to sell it off in pieces.”