Rupert Murdoch's $5bn (£2.5bn) takeover offer for Wall Street Journal-owner Dow Jones could ignite a bid battle for the iconic US media firm, analysts say.
Dow Jones' top shareholders say the Journal is not for sale
General Electric - which owns the business news network CNBC - and the Washington Post have been mentioned among potential counter bidders.
The surprise $60-a-share offer from Mr Murdoch's News Corporation sent Dow Jones shares soaring by 55% on Tuesday.
However, Dow Jones' biggest shareholder group said it was opposed to the bid.
The Bancroft family, which holds just under a quarter of Dow Jones stock but has more than 62% of shareholder voting rights, is understood to have told the company's board that it would block the move.
A successful bid would bring Dow Jones publications including the Wall Street Journal and Barron's under the same stable as News Corp's New York Post in the US and The Sun and The Times in the UK.
News Corp made its offer to Dow Jones shareholders in a letter two weeks ago.
Mr Murdoch says News Corp has made a 'generous' offer
Dow Jones investor Lawrence Haverty told Bloomberg News that he believed News Corp's bid could spark a wider struggle for control of 125-year old firm.
"Dow Jones is a fish in the pond, and there are sharks swimming around," he said in an interview with Bloomberg.
Shares in rival US news organisations such as the New York Times and McClatchy Newspapers jumped on news of the bid, although shares in UK financial news group Reuters were down more than 7% on Wednesday.
KEY DOW JONES ASSETS
Wall Street Journal
Far Eastern Economic Review
Dow Jones newswires
Analysts said acquiring Dow Jones, which owns Dow Jones newswires, would bolster News Corp's plans to launch a business news channel later this year under its Fox TV brand.
The move would also extend News Corp's reach in Asia, where Dow Jones publishes the Wall Street Journal Asia and the Far Eastern Economic Review.
"It would offer (News Corp) more of a base in that area," said media analyst Peter Cox. "China offers News Corp the possibility of being bigger than Europe and the US."
News Corp owns Hong Kong-based broadcaster Star TV, but has so far had little success in penetrating the fast-growing media market in mainland China.
Speaking on Fox News, Mr Murdoch said News Corp had made "a generous offer" for Dow Jones, adding that the Wall Street Journal was a prized asset.
KEY NEWS CORP ASSETS
New York Post
20th Century Fox
"We feel this is the greatest newspaper in America, one of the greatest in the world," he said.
"It has great journalists which deserve, I think, a much wider audience."
While many of the world's top newspapers have struggled to move into the digital age, the Wall Street Journal is one of a few that has managed to build a successful subscription-based online service.
Meanwhile, News Corp has been building its presence in the internet sector, buying the company behind MySpace in 2005 for $580m.
Mr Murdoch is understood to be seeking a meeting with the Bancroft family in the coming weeks to discuss News Corp's offer.
Dow Jones said on Tuesday that the offer was being considered, but added there could be "no assurance that this evaluation will lead to any transaction".
Shares in Dow Jones closed up 54.7% at $56.2 on the New York Stock Exchange on Tuesday.