The quiet rule change happened before the confetti settled. Index committees, most likely those running the Nasdaq Global Indexes, amended their inclusion criteria ahead of SpaceX’s June 12 debut. The public reason was straightforward: attract the largest IPO in history to list on the exchange.
The consequence, now visible in the technical details, is that a safety catch has been removed from the market’s most powerful engine. Passive funds are the engine.
They track indexes, buying whatever stocks get added. When a company enters a major index, these funds must purchase its shares regardless of price. The old rules had a buffer.
Newly public companies typically waited a quarter, sometimes longer, before inclusion. That gave the market time to find a fair price after the IPO euphoria faded.
The new rules compress that window, sometimes to days. SpaceX’s numbers show why this matters. The company raised $75 billion in its IPO, nearly tripling the previous record set by Saudi Aramco in December 2019.
It briefly touched a valuation of almost $3 trillion before the post-IPO gains were pared back. That kind of volatility is normal for a massive debut. What is not normal is forcing passive funds to buy at the peak, before the market has properly absorbed the stock.
The same dynamic threatens two more companies. Anthropic and OpenAI both filed confidentially with the Securities and Exchange Commission — Anthropic on June 1, OpenAI on June 8.
By June 18, secondary markets were pricing Anthropic at an estimated $965 billion and OpenAI at $909 billion. If either goes public under the new index rules, the same forced buying could amplify the initial surge, then worsen the eventual correction. The mechanism is simple.
Passive funds must buy at any price. If the hype fades and the stock corrects, those funds hold overvalued shares.
The correction itself can accelerate as index rebalancing forces selling. The Trump bull market has been fed by AI hype, a record-breaking SpaceX IPO, and share buybacks that hit an all-time high in 2025. The Dow rose 57 percent, the S&P 500 gained 70 percent, and the Nasdaq Composite surged 142 percent.
Those are extraordinary numbers. But they rest on a technical detail that can turn the tables. Index committees changed the rules to court the world’s largest IPO.
They succeeded. SpaceX listed, and the market celebrated.
The consequence is that newly implemented rules can now force stocks into indexes faster than the market can absorb them. The party continues. The champagne corks are still bouncing.
But the mechanism under the hood has been rewired, and the safety catch is gone.
