Shares in 21st Century Fox soared 9% on Monday following a market-rattling report from CNBC that the Murdochs have held talks in recent weeks to sell a large portion of their media conglomerate to Disney.

CNBC’s David Faber reported that the sale talks have centered around the 20th Century Fox movie and TV production operations, the FX Networks and National Geographic TV cable groups as well as Fox’s enormous portfolio of international channels.

The Murdochs maintain tight control of 21st Century Fox, as well as the separate News Corp. entity, through Rupert Murdoch’s control of nearly 40% of the voting shares in Fox. The notion of Rupert Murdoch as a seller comes as a shock to media biz watchers, given his legacy as the mogul known for his empire building in the 1980s and ’90s and his voracious appetite for acquisitions. Rupert Murdoch has long been seen as the consummate buyer, never a seller.

The deal, as reported by CNBC, would leave Fox with the Fox Broadcasting Co. network, the Fox Television Stations unit and the Fox Sports and Fox News operations. Those carve-outs are no surprise as FCC rules bar one company from owning more than one of the Big Four broadcast networks. Disney already owns ABC. The combination of Fox Sports with Disney’s ESPN and Fox News with ABC News might also raise anti-trust hackles.

Fox’s stock price shot up more than 6% within a half-hour of the CNBC report, which hit around 1:30 p.m. ET. Fox shares were up 9% at closing to $26.62, which is still well shy of its 52-week high of $31.94. Disney shares gained 2% to close at $100.64.

Reps for Disney and 21st Century Fox did not return calls seeking comment.

Fox at present is in the midst of a prolonged regulatory review in the U.K. to buyout the remaining 61% in European satcaster Sky that it does not already own. Word of the Disney sale talks could indicate a lack of confidence among the Murdochs that the acquisition will pass muster with regulators who have long wrestled with Murdochs’ influence over U.K. media.

Earlier Monday, U.K. regulator Ofcom censured the Fox News operation for violating “impartiality rules” with primetime shows hosted by Tucker Carlson and Sean Hannity. Fox News was pulled off the air in the U.K. in August by Sky, citing its tiny audience. But the rebuke from Ofcom is seen as more evidence that regulators are taking a dim view of Fox’s full-fledged Sky takeover.

CNBC reported that in considering a sale to Disney, the Murdochs believe a smaller operation more focused on news and sports might carve out a more competitive niche.

At present, 21st Century Fox is still a heavyweight industry player but it is dwarfed in size by Comcast-NBCUniversal, Disney, and the pending AT&T-Time Warner union. CNBC reported the Murdochs are concerned that 21st Century Fox is unable to achieve the global scale that traditional media giants need to stay competitive with the tech giants that have been actively diving into content and distribution: Facebook, Apple, Amazon, Netflix, and Google.

For Disney, the acquisition as reported would strengthen its market share in film — which is already considerable thanks to the Marvel, Pixar and Lucasfilm banners — and beef up its TV content production activity. Fox’s film and TV vault would also be a boon to the standalone entertainment streaming service that Disney plans to launch in 2019. Moreover, Fox has a much more significant presence in international TV than Disney through its portfolio of 300-plus channels across Europe, Asia, Latin America, Africa, and the Middle East.

Even if Fox’s Sky acquisition is ultimately nixed, Fox’s existing 39% interest in Sky would bolster Disney’s international TV footprint.

(Pictured: 21st Century Fox leaders Lachlan, Rupert and James Murdoch)