The proposal is one of two possible remedies offered by the US media giant to overcome objections to the takeover by the Competition and Markets Authority.
Both proposals include guarantees to fund a Sky-branded news channel in the UK for up to 15 years.
The regulator said at the end of January that it was minded to block the proposed £17.5bn takeover on the grounds that it would give the Murdoch Family Trust - a major shareholder in both Fox and News Corporation (Frankfurt: A1W048 - news) , owner of The Sun, The Times and The Sunday Times - too much influence over the UK media.
Fox subsequently offered to toughen "firewall" proposals previously tabled to guarantee the editorial independence of Sky News and promised to fund the channel for "at least" 10 years.
Today, though, the company went further with two new proposed remedies.
The first, a ring-fencing option, would see the creation of a new company, Newco, which would be a wholly-owned subsidiary of Sky and would own Sky News.
It would have between five and seven directors - three independent directors of Sky plc and two more nominated by those directors - and would be chaired by an "independent expert director" with experience of journalism at a senior level.
There would also be a separate editorial sub-committee with the power to hire and fire the head of Sky News and set the channel's editorial guidelines.
Under this arrangement, Fox has promised to continue funding Sky News for 10 years at the present level and for a further five years at a level "not materially different" from that.
Under the second proposal, which has been described as the "divestiture" of Sky News, Newco would be set up as in the first proposal.
Under this scenario, however, the moment that Fox had completed its takeover of Sky, Newco would be transferred to Disney - which, just before Christmas, tabled a separate $66bn offer for Fox's entertainment assets, including Sky.
That deal is currently being assessed by US regulators. This second proposal would see Disney guarantee to continue funding Sky News for five years at the present level and for a further five years at a level "not materially different" from now.
Both proposals resemble the way BT hived off its wholesale operation , BT Openreach, into a separate ring-fenced business last year.
The second proposal will raise eyebrows, though, because it represents a commitment by Disney to buy Sky News whether or not its wider takeover of Fox's entertainment assets goes ahead.
Both Fox and Disney had previously stressed that they did not wish to trade assets piecemeal but that they wanted Sky News to change hands only at the time of the bigger deal going through.
Announcing the proposals, Fox - which first announced plans to buy all of Sky in December 2016 - said: "We have worked diligently with the CMA throughout its extensive review.
"In fact, we believe the enhanced firewall remedies we proposed to safeguard the editorial independence of Sky News addressed comprehensively and constructively the CMA's provisional concerns…we remain committed to working with the CMA to find remedies that will ensure the continued editorial independence of Sky News.
"We will continue to work with the regulator, and then the Secretary of State at the appropriate time, and leave open the possibility to pursue all of our legal options if necessary.
"21st Century Fox has proved itself to be a genuine custodian of quality journalism over many decades.
"We retain a 39% stake in Sky and, subject to ultimately obtaining regulatory approval, remain focused on acquiring the remaining 61% of Sky."
Sky said: "Sky believes that both of these remedy proposals comprehensively address any plurality concerns the CMA may have, and would guarantee the long term future of Sky News and its ongoing editorial independence."
The CMA now has until 1 May to report back to Matt Hancock, the Secretary of State for Digital, Culture, Media and Sport, who has the final say on the matter.
Should Fox win regulatory approval for the takeover, it is widely expected to raise its offer for Sky.