Fox had wished to seal the deal in 2017 but it has been postponed by regulators.
It follows issues an offer would offer the household of entrepreneur Rupert Murdoch excessive control over UK news.
US-based Fox currently has a minority stake in Sky.
Both Sky and Fox are managed by Mr. Murdoch, who likewise owns the Times and the Sun papers. Fox is looking for to purchase the 61% of Sky it does not own.
In June, Culture Secretary Karen Bradley stated she was “minded” to refer the nearly ₤ 12bn (₤ 9bn) offer to the Competition and Markets Authority (CMA) for broader evaluation, based upon the dangers to media plurality.