Shares in Dow Jones have surged after Rupert Murdoch's media company News Corp made a bid for the newspaper firm that values it at about $5bn (£2.5bn).
Dow Jones confirmed reports that News Corp tabled a surprise $60-a-share offer in a letter two weeks ago.
But the family holding most of Dow's shares says it will oppose the sale.
Dow Jones is one of the world's biggest news groups controlling the Wall Street Journal, Barron's, Marketwatch, the Dow Jones wire services, and Factiva.
While News Corp said it had made "a friendly offer", Dow Jones described the move as "an unsolicited proposal".
The Bancroft family, which owns 62.4% of Dow shares has indicated that it will not accept the offer - which analysts say may push the price higher - and possibly tempt other would-be buyers.
But it also "puts the onus on the family to prove to the shareholders that they can operate this business better than Murdoch could", said Todd Bourell, of hedge fund ValueAct.
On Wall Street, shares in Dow Jones closed 47.5% higher at $53.60 on Tuesday.
While many of the world's top newspapers have struggled to move into a more digital age, the Wall Street Journal is one of a few that has managed to build a successful subscription-based online service.
Even so, the company's shares have been under pressure as investors have questioned the outlook for an industry that relies so heavily on advertising revenues.
Analysts said that News Corp, owner of The Sun and The Times in the UK, would only have made the offer if it believed that it could merge the two businesses and significantly cut costs.
It would also give Mr Murdoch a much bigger role in financial publishing.
Dow Jones said that while the offer was being considered, there could be "no assurance that this evaluation will lead to any transaction".