Fortune reached out to Blair Effron, a partner at Centerview Partners, which has advised the Murdoch family on investment decisions. He said, “As a friend of James, I’ll pass on speaking.”  A representative for James Murdoch had no comment at press time.

The financials are based on details of James’ holdings found in public records. 

A 2023 court case brought by a Tesla shareholder challenging Musk’s controversial $56 billion compensation package revealed that James had bought three separate tranches of stock in SpaceX. Two of those tranches, worth $50 million each, were acquired in 2019 and 2020 via a private investment firm, thought to be Murdoch’s Lupa Systems, where he is the primary beneficiary, along with staff and partners. He separately bought another $20 million as a personal investment in 2019. Those stakes together are now estimated to be worth between $6.573 billion and $7.44 billion, according to the Pitchbook estimate. 

While the SpaceX S-1 document attached to its public offering, doesn’t mention James Murdoch, it details stock awards to its chief financial officer, Bret Johnsen, that have an expiration date of 2030 and value the stock at $4.40—numbers that give clues as to the value of owned by shareholders before the IPO.

There are, however, a series of caveats. James Murdoch could have sold those SpaceX shares along the way, and there have been several dilutions. The company approved a five-to-one stock split in May, for instance. The precise dates of the stock acquisitions are not publicly known, but media industry executives have been exchanging rumors about the junior Murdoch’s astonishing potential windfall. 

The former chief executive of 21st Century Fox was already a multi-billionaire. He stepped down from Fox after the majority of its assets were sold in a $71.3 billion deal with Disney in 2019, garnering him $2.2 billion in proceeds. 

James’ split with his father became final when the elder Murdoch rejected him in favor of his brother Lachlan to succeed Rupert atop News Corp.

Last year, a Nevada probate court examined a move by Rupert and his eldest son Lachlan Murdoch to change a longstanding Murdoch Family Trust, which had been designed to protect the financial interests of all six Murdoch children. A probate commissioner ruled against the change that would have stripped voting rights from James and his sisters Liz and Prue. After an appeal, the parties came to an agreement that resulted in each of the three siblings receiving a $1.1 billion payout. The agreement stipulated that Murdoch children shed their stock in News Corp and Fox. 

The private fight spilled out into public view after the New York Times and The Atlantic revealed the full extent of the animosity between James Murdoch and his father. The two no longer speak. The Atlantic published an interview with James, who believed his father was feeding questions to a lawyer. One of the questions posed was, “Have you ever done anything successful on your own?” 

James first met Musk in the late nineties, according to the court filings in the shareholder fight. At that time, Musk was building Zip2, an online guide to cities and businesses for newspapers while James was running digital operations at what was then known simply as News Corp, before Fox split off.  The two men reconnected after James ordered an electric Tesla Roadster in the middle of the 2000s. They continued to meet up and went on family vacations to Israel, Mexico, and the Bahamas. After one of the trips, Musk talked to his brother Kimbal and later added James Murdoch to the Tesla board, according to an account in the court documents from the now-resolved compensation battle. 

James Murdoch has profited handsomely from his Tesla shares, which he holds within JRM Rev Trust and another financial entity called Seven Hills Trust. Tesla share sales have netted the JRM Rev Trust $107 million since Spring last year, according to SEC documents. Tesla also owns 19 million shares in SpaceX, potentially benefiting James Murdoch. There are Street rumors that Tesla may be folded into SpaceX too. 

James is currently listed as an independent director who joined Tesla in July 2017. 

The revelations give weight to the idea that James Murdoch has been a canny investor since his exit from Fox. Musk was spotted sitting with Rupert and daughter Liz Murdoch at the Super Bowl in 2023 and shared that he had discussed his Dogecoin initiatives. That was the year Rupert and Lachlan tried to figure out a way to change the irrevocable family trust to solidify Lachlan’s control over the companies, ostensibly to avoid disputes boiling over after Rupert passes away—a move that ultimately triggered the probate fight. 

James has been setting his own course since the Disney sale, establishing his own investment firm Lupa Systems in New York in 2019. That year, SpaceX began launching broadband satellites that became part of Starlink, a business that James Murdoch knows well, having run two satellite pay-TV ventures, Sky in the U.K. and Star in Asia. 

After exiting Fox, James began investing in a host of businesses both in the media and beyond. Most recently, he made a $300 million deal to acquire a large portion of Vox Media, owner of New York magazine, a brace of niche websites, and a collection of podcasts from the likes of tech journalist Kara Swisher and Professor Scott Galloway. 

He has made a host of other investments that span the arts, including comic book publisher and studio AWA; Tribeca Enterprises, the Robert De Niro and Jane Rosenthal-helmed Tribeca Film Festival owner; and MCH Group, the holding company of global art show Art Basel. James is also invested in a streaming media service joint venture in India through Bodhi Tree Systems, which received funds from Comcast and the Qatar Investment Authority. 

“To me this is no surprise, James has been a savvy global technology investor for decades,” said Jon Miller, the chief executive of TPG-backed Integrated Media. Miller is a former CEO of AOL and was the chief digital officer at News Corp overseeing Hulu.

Veteran media analyst Brian Wieser of media and marketing focused advisory firm Madison and Wall believes it’s very hard to say with certainty what the actual potential windfall might be but acknowledges it’s likely significant if James Murdoch bought shares at $4.40 in 2020 those shares, and the ones acquired in 2019 have grown 33x. 

He said: “Given that James Murdoch has been in the SpaceX orbit for a while, since Tesla, it’s unsurprising that he’s benefited financially. And if so, it’s very plausible that someone like James Murdoch could end up making a lot more from the holdings of SpaceX than they ever would from holding traditional media companies. Though that presumes they can get liquid, holding the shares doesn’t mean anything if you can’t sell them.”—With reporting by Amanda Gerut.

Claire Atkinson is the author of an upcoming new biography of Rupert Murdoch for Grand Central Publishing, scheduled to be published in 2027.