SpaceX Enters Nasdaq-100 as Grantham Calls It Craziest IPO

SpaceX joined the Nasdaq-100 at a capped ~1% weight as Jeremy Grantham dubbed its IPO the 'craziest in the history of man' and bet 90% on a crash.

SpaceX (SPCX) entered the Nasdaq-100 at the start of trading on Tuesday, triggering automatic buying from index-linked funds including Invesco's QQQ under rules designed to fast-track newly public megacaps. According to Stocktwits, the company sold less than 5% of its shares in its June 12 IPO, so the index is expected to cap its weight at roughly 1% to 1.3% — far below what its reported $2 trillion market value would otherwise imply. The stock slipped 1% on Monday, extending a weekly decline.

The debut puts passive index demand against one of the market's most famous bears. In a Morningstar interview cited by Stocktwits, GMO strategist Jeremy Grantham — known for calling the Japan, dot-com and 2008 housing bubbles — called SpaceX the 'craziest IPO in the history of man' and said the company is 'rolling in red ink.' He still acknowledged that supply and demand being what they are, the price may rise sharply on forced buying, but said he would 'bet at least 90%' on a crash rather than the valuation being justified.

Grantham's core objection is that much of the long-term case rests on aggressive AI assumptions. According to Stocktwits, he argued that 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 — rivals preparing mega public listings at private valuations of about $965 billion and $852 billion respectively. He also questioned the space-travel ambitions in the prospectus, saying serious physicists would view them as 'utterly inconceivable.'

TradingKey reports that SPCX priced its June 12 IPO at $135, opened at $150, spiked past 30% intraday to $176.52, and closed its first session at $160.95 — a 19.2% gain over the offer price. As of mid-June it traded at $171.91, and TradingKey's analysis flagged $176.50 as the breakout level with Fibonacci extension targets at $183.96 and $185, supported by MSCI inclusion and a constrained float under a 180-day insider lockup.

Both publications flag the same core risk: scarcity today, more supply tomorrow. Stocktwits reports insider lockups begin expiring in tranches 70 to 135 days after the IPO, with Elon Musk's shares and certain large-holder restrictions locked for about a year. TradingKey adds that the December 2026 expiry of the 180-day lockup is the next major supply event, and identifies the September 2, 2026 earnings report — the first to show Starlink subscriber growth, xAI capex and Starship launch cadence as reported numbers — as the fundamental anchor that will decide whether the post-IPO valuation holds or compresses.

The crowd is already shifting. Stocktwits reports that retail sentiment for SPCX flipped to 'bearish' 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. Traders on the platform are watching the mechanics closely, with one user noting that only about 10% of index inclusion had happened by Monday and the largest bulk would occur Tuesday around 3 PM — meaning the forced-buying story still has chapters to run.