FILE PHOTO: SpaceX logo and miniature satellite model are seen in this illustration created on March 10, 2025. REUTERS/Dado Ruvic/Illustration/File Photo

Dec 5 (Reuters) - Elon Musk's SpaceX is kicking off a secondary share sale that would value the rocket-maker at $800 billion, the Wall Street Journal reported on Friday, pitting it against OpenAI for the title of the most valuable private company.

SpaceX's finance chief, Bret Johnsen, told investors about the sale in recent days, the report said, citing people familiar with the matter. The $800 billion valuation is double the $400 billion value it fetched in a recent secondary share sale.

The company did not immediately respond to a Reuters request for comment.

The $800 billion valuation would put SpaceX ahead of ChatGPT-parent OpenAI, which is valued at $500 billion as of October, making it the most valuable privately held company in the world, according to Crunchbase data.

Several billionaires and private firms, including SpaceX and Jeff Bezos' Blue Origin, are fueling a new space race in the U.S., pouring money into rockets, satellites and lunar missions.

(Reporting by Juby Babu in Mexico City; Editing by Alan Barona)