Jim Cramer urges caution as SpaceX IPO set to begin trading on Friday

CNBC host Jim Cramer has raised the alarm over SpaceX's highly anticipated stock market debut, warning on Thursday that runaway demand could briefly push the company's valuation to $4–5 trillion before an inevitable and damaging correction sets in.

"Tomorrow at this time, if things really go awry, we may have a new champion, a new largest stock in the world: SpaceX," the Mad Money host said on air.

IPO priced at $135 per share amid extraordinary demand

Elon Musk's rocket and artificial intelligence company set a fixed sale price of $135 per share ahead of its Friday trading debut, placing its valuation at $1.77 trillion. The deal has been reported as four times oversubscribed, reflecting a level of enthusiasm that Cramer said is as much a cause for concern as it is a vote of confidence.

In his assessment, the strongest IPOs open modestly above their offering price and then trade in a calm, orderly manner. SpaceX, however, faces an unusual collision of institutional demand, retail enthusiasm, and anticipated index buying — a combination Cramer believes could send shares sharply higher the moment trading opens.

'New, unguided missiles'

Cramer expressed particular concern about the wave of inexperienced investors placing market orders rather than limit orders, a practice that can inflate a stock's price to levels that are impossible to sustain. "These are new, unguided missiles who can't be controlled," he said.

Should enough buyers rush in simultaneously, Cramer said SpaceX could momentarily command a valuation rivalling or surpassing the world's largest publicly traded companies — but he cautioned that such moves rarely hold. "Can a $4 to $5 trillion stock really be at hand? For a few minutes perhaps, just as long as it takes to gaffe a marlin," he said. "That's a terrific catch, but if it isn't stuffed and mounted fast, it stinks to high heaven."

Recent IPO flops cited as a warning

Cramer pointed to the post-debut trajectories of Figma, which listed in July 2025, and Cerebras, which debuted in May, as cautionary examples. Both stocks, he noted, "continued to go higher and then they started the long descent."

His position is that a controlled, measured debut is far preferable to a first-day spectacle. "We want the deals to be under control because otherwise it can be disastrous," he said.