Their decision means that Murdoch has the support of at least 38 per cent of the voting shares owned by the Bancrofts, an amount considered more than enough to approve the deal, especially since the institutional investors who control the remaining shares strongly support the deal.

For the Bancroft family it was a sudden change of heart, because previously they had held out against the deal for fear that the aggressive media mogul would compromise the paper's renowned editorial independence.

In May, Rupert Murdoch, the media mogul, offered $5 billion for Wall Street Journal and in June the media reports said that Dow Jones & Co and News Corp have agreed on a set of editorial protections.

The buyout is expected to easily pass a formal shareholders' vote, allowing Murdoch to add one of the most respected brands in journalism to his corporate stable. News Corp already owns the Fox Network, Sky Broadcasting, and the Times of London.

In addition to the Wall Street Journal and its international and online editions, Dow Jones publishes Barron's and SmartMoney magazines and other periodicals, DowJones Newswires, Dow Jones Indexes, Factiva news database and the Ottaway group of community newspapers.

Previously the British publisher Pearson has tried to make an offer for Dow Jones, together with General Electric, but the negotiations were abandoned.