LONDON (AP) – Directors of British Sky Broadcasting said yesterday they have rebuffed a buyout offer from Rupert Murdoch's News Corp. that values the company at £12 billion ($17.7 billion), but were willing to back a sweeter bid.

News Corp., which owns The Sun and The Times newspapers in London, is already BSkyB's biggest shareholder with a 39 percent stake. Murdoch's son, James, is BSkyB's chairman.

Shares in the company were up nearly 21 percent to 724.5 pence in early trading in London.

Independent directors said News Corp.'s informal offer of 700 pence per share was too low.

The directors say they would have backed an offer above 800 pence, which would value the company at about £13.7 billion.