"The media plurality concerns identified mean that, overall, the CMA provisionally concludes that the proposed transaction is not in the public interest".
The business added: "Regarding plurality, we are disappointed by the CMA's provisional findings".
The CMA is now welcoming responses from interested parties to its proposed findings, including views on Fox's announcement in December 2017 to sell certain assets, including its interests in Sky, to The Walt Disney Company.
However, the CMA found the deal would not be against the public interest in relation to meeting broadcasting standards in the UK.
The Competition and Markets Authority has provisionally found that 21st Century Fox's planned takeover of Sky is not in the public interest due to media plurality concerns.
Disney had hoped that Murdoch would have taken full control of the European broadcaster by the time the USA group completed its takeover.
These could include spinning off or divesting Sky News, or insulating Sky News from Fox's influence. The firm will continue to engage with the CMA ahead of the publication of the final report in May.
The broadcaster said it still expects to be given the green light by regulators.
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The 14-year-old's kidneys and lungs began to fail and his physicians were ultimately unable to save him. He added that his team's hopes of allowing Zayas a better quality of life "have not been realized".
Murdoch already owns The Times and The Sun newspapers in the United Kingdom and there are fears his 100% ownership of Sky, including its Sky News operation, could give him too much influence.
The CMA added that Fox had a "genuine commitment" to broadcasting standards and recent allegations of sexual harassment against Fox News employees in the USA were not related to standards in the UK.
Media plurality goes to the heart of our democratic process.
THE UK COMPETITION regulator has ruled that a takeover of Sky by Rupert Murdoch's 21st Century Fox entertainment group is "not in the public interest".
The CMA said on Tuesday that the deal as proposed went against the public interest because it would give the Murdoch family too much control over the provision of news.
Other news outlets would not be sufficient to "moderate or mitigate" the influence of MFT if the deal went ahead, the CMA reported.
"The CMA has provisionally found that if the deal went ahead, as now proposed, it is likely to operate against the public interest", it added.
The watchdog has until 1 May to provide a final report to the Culture Secretary, who will make the final decision on its findings. Sky's shares rose by 2.5% in early trading.