Elon Musk’s X may be flailing, but another company owned by the billionaire is on track to reach dizzying heights. Musk is in talks to sell between $500 million and $750 million of SpaceX stock at a valuation of $175 billion or more, Bloomberg reported Wednesday, citing unnamed sources. The figures mean the private space giant, which still hasn’t announced plans to go public, is more highly valued than any initial public offering in U.S. history, topping Alibaba’s $169 billion IPO valuation from 2014.

The latest private market valuation for SpaceX also marks a substantial increase over the $150 billion valuation the company enjoyed in July, when new and existing investors bought $750 million of stock. And it would make SpaceX more highly valued than American corporate giants like Disney, which has a $170 billion market cap, and Comcast, which is worth just over $171 billion.

That’s in stark contrast to another Musk property, X—formerly Twitter—which has plummeted in value since Musk took it private a year ago. Insiders report that X employees have been offered stock at a $19 billion valuation in October, while other calculations suggest X’s value could be as low as $4 billion.

The terms and size of SpaceX’s tender offer could change. And SpaceX did not immediately respond to Fortune’s request for comment on the latest private market valuation.

Elon Musk’s SpaceX is expected to bring in revenues of $9 billion in 2023, rising to roughly $15 billion next year, Bloomberg reported last month. The company has developed a dominant position in the space transportation market, executing over 64% of commercial rocket launches to send satellites, scientific instruments, and other payloads to orbit globally in the first six months of this year.

Musk has assembled a deep roster of industry talent at SpaceX as he attempts to take market share in both space transportation and satellite markets, including former leading NASA engineers and Apple product designers. Starlink, SpaceX’s satellite business which hopes to provide internet coverage in 60 countries, focusing on hard to reach areas, saw its revenues surge from $222 million in 2021 to $1.4 billion last year, the Wall Street Journal reported in September.

The impressive performance led to rumors last month that SpaceX may spin off and IPO Starlink as soon as late 2024. But Musk called those reports “false,” and billionaire Tesla and SpaceX investor Ron Baron said that he doesn’t expect a Starlink public offering until 2027.