Fox, owned by Rupert Murdoch, is now willing to keep running Sky News for at least 10 years, double the amount it previously promised the Competition and Markets Authority (CMA).
The CMA last month said the takeover bid raised media plurality concerns because it would give the Murdoch family too much power over the UK media.
Fox’s sweetened offer brings it closer in line with a 10-year funding commitment made in 2011 in a failed attempt to buy the 61% of Sky that it does not already own.
But the deal is weaker than in 2011 because Fox said Sky News would be guaranteed funding at the current level for five years and then at least five more years of money “at a level to be determined at the time”.
Fox has also strengthened its offer to shield Sky News against any Murdoch influence.
It had already said it will create an independent board for Sky News but the new offer promises to give annual updates on editorial independence.
The revised offer also gives the board the right to nominate a candidate for head of Sky News when the time comes to replace the incumbent John Ryley.