Bradley had in late June said that she was "minded" to take the approach of an extended analysis on competition grounds after reviewing a report from United Kingdom media regulator Ofcom, which had analyzed the deal's effects on competition, or media plurality, and commitments to editorial standards.
CMA reviews typically take around six months.
She said: "The fact that Fox belatedly established such procedures does not ease my concerns, nor does Fox's compliance history".
The Culture Secretary went on to say that Ofcom had concluded concerns over corporate governance failures do not warrant a referral.
State Street Corp., the custodial bank that runs the S&P 500 ETF Trust, voted against re-electing media mogul Rupert Murdoch and two of his sons to board positions at News Corp. and Twenty-First Century Fox in the most recent election.
The culture secretary said she had received 43,000 representations over the summer following her initial statement, few of which added substantial new evidence.
In a statement, Sky said that it was disappointed by the delay and that the Secretary was minded to refer the takeover to the CMA on the grounds of broadcasting standards despite Ofcom maintaining its advice that there are no sufficient concerns to warrant such a referral. She remarked that she had outstanding non-fanciful concerns about these matters and was of the view that they should be further considered by the CMA.
Before I come to a final decision, I am required - under the Enterprise Act 2002 - to allow the parties to make representations on my proposed decision, and this is the reason my decision at this stage remains a minded-to one.
Bradley summarized: "My proper concern is whether Fox will have a genuine commitment to attaining broadcasting standards objectives". She was not confident that weaknesses in Fox's corporate governance arrangements were incapable of affecting compliance in the broadcasting standards context.
Fox said it still expects the deal to close by June 30 2018, barring any "further delays" to the process.
The British government will refer Twenty-First Century Fox Inc.'s bid for satellite broadcaster Sky to the country's competition regulator for further examination, in a blow to Rupert Murdoch's takeover plans.
Shares of Sky, which are valued at 1075p each under the proposed takeover, fell by 5% when Ms Bradley announced her decision to the Commons.
Fox News has fallen foul of the United Kingdom code seven times in recent years, including four times last year, one of which was for a programme that featured a guest who said Birmingham was a city "where non-Muslims just simply don't go".