Elon Musk’s SpaceX is set to begin trading on the Nasdaq on June 12 in what may be the largest IPO ever, but one prominent investor says the numbers no longer add up.

Steve Eisman, the investor made famous by “The Big Short,” called the SpaceX valuation “crazy” on his latest weekly podcast and said the company’s push into AI has made the story “far riskier.”

A Capex Ratio That Has Exploded

Eisman pointed to one figure in the S-1 that he said reframes the entire story.

In fiscal year 2023, SpaceX generated $10.4 billion in revenue against $4.4 billion in capex, a capex-to-revenue ratio of 42%, according to Eisman.

In the first quarter of fiscal 2026, that ratio climbed to 215%, on $4.7 billion in revenue and $10.1 billion in capex.

Pre-AI SpaceX was relatively capital efficient because it could reuse its rockets, Eisman said. The AI division has changed that.

“By adding AI to its business mix, SpaceX has gone from a capital efficient company to an incredibly capital intensive one,” Eisman said.

The company is now competing for AI infrastructure against Alphabet (NASDAQ:GOOGL), which is raising $80 billion in equity this year to help fund its own AI buildout.

Growth That Does Not Match The Multiple

Eisman said SpaceX’s reported 15% revenue growth in the first quarter is “fine, but it is less than every trillion dollar market cap company.”

He contrasted that with Nvidia (NASDAQ:NVDA), which posted 85% revenue growth in its most recent quarter. The S-1’s $28.5 trillion total addressable market is mostly tied to AI, and Eisman said Grok is not yet considered a world class product.

Eisman framed SpaceX as the “punctuation point” on a shift in how IPOs get priced, away from institutional dog and pony shows and toward retail FOMO. He had previously warned investors the stock could become a “retail cult stock.”

Major indices have also abandoned their traditional wait-and-see rules for new issues, Eisman said, meaning passive and pension funds may be forced to buy SPCX at inflated valuations.

What Prediction Markets See

Retail demand has not flinched. On Polymarket, traders assign a 67% probability that SPCX closes above a $2 trillion market cap on day one, with more than $7.5 million in volume.

Kalshi traders are pricing a 56% chance that SpaceX merges with Tesla (NASDAQ:TSLA) before May 2027, a tie-up that would consolidate Musk’s AI ecosystem under one ticker.

Anthropic confidentially filed for its own IPO this week and OpenAI is expected to follow, setting up a test of Wall Street’s appetite for mega-cap AI offerings.

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