James Murdoch stands to reap an enormous financial gain from his investment in Elon Musk's SpaceX, a sum that could dwarf the wealth he accrued from his father's media empire.

Now 53, James has long been estranged from his father, Rupert Murdoch. Before SpaceX completes what is expected to be the largest initial public offering (IPO) in history this year, James had invested approximately $120 million into the company. According to calculations by Franco Granda, a senior private markets analyst at PitchBook, James's stake could now be worth up to $7.5 billion, a valuation not previously disclosed publicly.

This success serves, in part, as a pointed rebuttal to his father. During the height of the family's internal power struggles, Rupert Murdoch reportedly had lawyers advance the argument that his youngest son would achieve nothing significant without him.

The financial estimates are derived from details of James's holdings found in public court filings.

In 2023, a Tesla shareholder lawsuit challenging Musk's controversial $56 billion compensation package revealed that James purchased SpaceX shares in three tranches. Two of these, each worth $50 million, were acquired in 2019 and 2020 through a private investment firm widely believed to be Murdoch's Lupa Systems, where James is the primary beneficiary alongside other employees and partners. In 2019, he also made a separate personal investment of $20 million. PitchBook estimates these holdings are now valued between $6.573 billion and $7.44 billion.

While James Murdoch is not named in SpaceX's S-1 IPO registration filing, the document details equity grants to Chief Financial Officer Bret Johnsen. These grants, with an exercise price of $4.40 per share and an expiration in 2030, provide a reference point for valuing pre-IPO shareholder stakes.

However, this valuation carries several uncertainties. James Murdoch may have sold some SpaceX shares in the interim, and the company's equity has undergone multiple rounds of dilution.