SPCX Stock Slides Ahead Of Nasdaq-100 Debut: Billionaire Value Investor Says Its ‘Third-Rate’ AI Is Getting ‘Kicked Around’ By Anthropic, OpenAI

• Its initial index weight is expected to be limited to about 1% to 1.3% because less than 5% of shares were sold publicly.
• Insider lockups could create future selling pressure, with some restrictions expected to expire 70 to 135 days after the June 12 IPO.
• Jeremy Grantham criticized SpaceX’s valuation, calling it the “craziest IPO in the history of man” and saying the company is “rolling in red ink.”

SpaceX entered its Nasdaq-100 debut week under pressure, with passive index demand set to kick in even as Jeremy Grantham questioned whether the company’s AI-driven valuation can withstand scrutiny.

SPCX stock fell 1% on Monday, extending a pullback after losing another 1% over the past week. Shares were also down 2% overnight late Monday. 

SpaceX Joins Nasdaq-100

SpaceX is set to enter the Nasdaq-100 at the start of trading on Tuesday, triggering automatic demand from index-linked mutual funds and ETFs, including Invesco’s QQQ. The company was fast-tracked into the benchmark under rules designed to include newly public megacap companies sooner. Still, its initial index weight is expected to be limited by its small public float.

SpaceX sold less than 5% of its shares in last month’s public offering, while employee and insider lockups restrict additional supply. Since Nasdaq adjusts weights based on free float, SpaceX is expected to enter with an index weight of about 1% to 1.3%, far below what its $2 trillion market value would otherwise imply.

The Nasdaq-100 debut also comes with a future supply risk. Some insider lockups are expected to expire in tranches between 70 and 135 days after SpaceX’s June 12 IPO, while CEO Elon Musk’s shares and certain large-holder restrictions are expected to remain locked for about a year.

Jeremy Grantham Slams SPCX Valuation

The index debut comes as Grantham, investment strategist at GMO, criticized SpaceX’s valuation. Grantham is a legendary value investor known for repeatedly warning about major market bubbles, from Japan in 1989 and the dot-com peak in 2000 to the 2008 housing crisis and today’s AI-driven valuations.

In a Morningstar interview, Grantham called SpaceX the “craziest IPO in the history of man,” arguing that investors may look back on the prospectus decades from now as a symbol of market excess. He said the company is “rolling in red ink” despite its towering valuation, and argued that much of the long-term case rests on aggressive AI assumptions. Grantham said 90% of the projection depends on SpaceX’s “currently third-rate AI offering,” which he said is being “kicked around the block” by Anthropic and OpenAI.

xAI, acquired by SpaceX in an all-stock deal in February 2026 and now being rebranded as SpaceXAI, gained further momentum in June with SpaceX’s $60 billion all-stock acquisition of Cursor parent Anysphere. The deal is expected to bolster Grok by combining Cursor’s coding intelligence and developer data with xAI’s Colossus supercluster. The AI push is unfolding as rival AI leaders Anthropic and OpenAI prepare for mega public listings, with private valuations of about $965 billion and $852 billion, respectively.

Grantham acknowledged that index inclusion could lift the stock in the short run as forced buying may outstrip available supply: “So supply and demand being what it is, it’s hard to imagine the price won’t go up, and perhaps it will go up a lot.” But he warned that the longer-term risk remains severe, saying he would “bet at least 90%” on a crash rather than SpaceX ultimately justifying its current valuation.

Grantham also questioned SpaceX’s broader AI and space assumptions, saying some productivity claims show “no idea what they’re talking about” and that much of the space-travel ambition in the prospectus would be viewed by serious physicists as “utterly inconceivable.”

How Do Retail Traders Feel About SPCX?

On Stocktwits, retail sentiment for SPCX flipped to ‘bearish’ levels over the past week from ‘extremely bullish’ levels at the time of listing amid a massive 26,150% surge in message volumes over the past month.

One user said, “$SPCX The 'Forced' Buying begins. Puts will go to ZERO.”

Another user said, “$SPCX only about 10% of the inclusion has actually happened. The largest bulk will occur tomorrow around 3 PM.”

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