SpaceX is preparing to sell insider shares in a transaction that would value Elon Musk’s rocket and satellite maker at as much as $800 billion, people familiar with the matter said, reclaiming the title of the world’s most valuable closely held company.

SpaceX has informed investors and representatives of financial institutions that it plans to pursue an initial public offering in the second half of next year, the Information reported on Friday, citing two people familiar with the discussions.