SpaceX is moving forward with an insider share sale that values Elon Musk’s rocket and satellite maker at about $800 billion, setting up what could be the largest initial public offering of all time.

In a company message seen by Bloomberg on Friday, SpaceX said it’s preparing for a possible public offering in 2026 that would be aimed at funding an “insane flight rate” for its developmental Starship rocket, artificial intelligence data centers in space and a base on the moon.

The per-share price of $421 in its latest secondary offering, laid out by Chief Financial Officer Bret Johnsen in the memo to shareholders, is nearly double the $212 a share set in July at a $400 billion valuation.

The valuation vaults past the previous record of $500 billion that ChatGPT owner OpenAI set in October, making SpaceX once again the world’s most valuable closely held company.

If Musk decides to proceed with the IPO, it would be another splashy venture for him, but it would hinge on a series of ambitious and risky plans that SpaceX would have to pull off in the coming years.