CNBC host Jim Cramer has cautioned that the extraordinary demand surrounding SpaceX could create a volatile and potentially unsustainable rally when the company begins trading, warning that excessive investor enthusiasm may become one of the biggest risks facing the historic market debut.
Speaking on CNBC’s Mad Money on Thursday, Cramer said he was concerned that a combination of institutional demand, retail speculation, and anticipated index-fund buying could drive SpaceX shares sharply higher immediately after listing, potentially pushing the company’s valuation to levels detached from market fundamentals.
“Tomorrow at this time, if things really go awry, we may have a new champion, a new largest stock in the world: SpaceX,” Cramer said.
Register for Tekedia Mini-MBA edition 20 (June 8 – Sept 5, 2026).
Register for Tekedia AI in Business Masterclass.
Join Tekedia Capital Syndicate and co-invest in great global startups.
Register for Tekedia AI Lab.
The warning comes as investors prepare for what is expected to be one of the largest and most closely watched initial public offerings in market history. SpaceX has set its IPO price at $135 per share, implying a valuation of approximately $1.77 trillion and instantly placing it among the world’s most valuable publicly traded companies.
Demand has been overwhelming. Reports indicate that investor orders exceeded available shares by roughly four times, underscoring the intense appetite for exposure to Elon Musk’s space, satellite communications, and artificial intelligence ambitions.
While heavy oversubscription is generally viewed as a sign of confidence, Cramer argued that it can also create instability if investors rush into the stock without regard to valuation.
Historically, the healthiest IPOs are those that rise modestly after listing and then build momentum gradually as investors assess the company’s prospects and earnings potential. SpaceX, however, may not follow that script.
The company enters public markets with a powerful combination of factors that could fuel aggressive buying pressure. Retail investors have been granted unusually large access to the offering, brokerage firms have lowered participation requirements, and market participants expect major benchmark indexes to eventually add the stock because of its enormous market capitalization.
That combination has raised concerns that investors may chase the shares higher immediately after trading begins. Cramer singled out inexperienced traders as a particular concern, especially those using market orders rather than limit orders.
“These are new, unguided missiles who can’t be controlled,” he said.
By this statement, Cramer supports growing concerns among market professionals that the IPO could become a speculative event rather than a conventional public offering. Similar dynamics have played out in previous high-profile listings, where first-day euphoria was followed by sharp corrections once excitement faded and investors began focusing on valuation metrics.
The debate surrounding SpaceX is particularly intense because the company is being valued not only on its current businesses, including Starlink and launch services, but also on ambitious long-term opportunities ranging from artificial intelligence infrastructure to space-based computing and future Mars-related projects.
That has led some analysts to assign valuations far beyond traditional earnings-based models.
Cramer warned that a dramatic first-day rally could briefly push SpaceX’s market value into territory normally reserved for the largest corporations in history.
“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 history offers examples of how quickly enthusiasm can reverse. Cramer pointed to companies such as Figma and Cerebras, which enjoyed strong initial trading performances before later retreating from their highs.
“They initially continued to go higher and then they started the long descent,” he said.
The SpaceX debut is also being viewed as a test of investor appetite for a new generation of mega-cap technology listings. The offering comes ahead of anticipated public market debuts from AI leaders, including OpenAI and Anthropic, making its performance a potential barometer for future IPO activity.
A successful and orderly debut could strengthen confidence in the market’s ability to absorb multi-trillion-dollar technology listings. Conversely, a sharp spike followed by a rapid selloff could raise concerns about speculative excess in the AI investment boom.
For that reason, Cramer argued that stability matters more than headline-grabbing gains.
“We want the deals to be under control because otherwise it can be disastrous,” he said.
His warning means that investors still face the unusual challenge of balancing the enormous promise attached to one of the world’s most closely watched private companies against the risk that excitement surrounding the offering may temporarily outpace economic reality.