Three of the most valuable private companies in the world — SpaceX, OpenAI and Anthropic — are preparing to sell shares to the public in what bankers are calling a once-in-a-generation IPO wave. SpaceX's listing alone, expected next month at a valuation of roughly $1.75 trillion, would be the largest IPO on record. OpenAI is filing paperwork within days, and Anthropic is not far behind. Between them, the three companies will raise tens of billions of dollars from investors who are unusually hungry for anything connected to artificial intelligence.
But the story is not really about the companies. It is about a small rule change that turns these IPOs into a market-wide event. The Nasdaq exchange recently introduced 'fast entry' rules that allow giant new listings to join the Nasdaq 100 — its flagship index of the 100 largest non-financial companies — after only 15 trading days, down from a traditional waiting period of three to twelve months. Nasdaq also waived its usual requirement that at least 10% of a company's shares be publicly available, a condition SpaceX could not have met. The exchange tweaked these rules partly to beat its rival, the New York Stock Exchange, in winning the SpaceX listing.
Here is why that matters. Trillions of dollars sit in passive funds that mechanically replicate the Nasdaq 100. Once a stock joins the index, those funds must own it — at whatever price the market happens to be charging. JPMorgan estimates that if half of SpaceX's shares eventually float at a $2 trillion valuation, passive investors would need to sell roughly $95 billion of Wall Street's eight biggest existing tech stocks just to make room. Smaller members of the Nasdaq 100 face a different threat: many are likely to be bumped out of the index entirely, and hedge funds are already betting against these 'marginal' names in anticipation.
The mechanical nature of this buying creates a strange incentive. One strategist noted that if SpaceX rises 100% in its first week, passive funds still have to buy at the inflated price — 'they can't discriminate.' Critics worry that 15 days is too short for genuine price discovery, meaning index investors could be locked into whatever volatile valuation the first two weeks of trading produce. Investor lock-ups, which traditionally prevent insiders from selling for 180 days, will also begin to expire, adding another wave of supply.
For Elon Musk personally, the listing is transformative. He holds roughly 5.1 billion vested shares — about 41% of SpaceX — which could be worth around $700 billion, potentially making him the world's first trillionaire. A special class of stock also gives him 85% of SpaceX's voting power, meaning that even after going public he retains nearly total control. Combined with his existing grip on Tesla, the IPO would hand one person dominant influence over two of the most valuable companies in America — a concentration of corporate power without modern precedent. Whether ordinary savers, whose retirement accounts will quietly absorb SpaceX shares the moment the index updates, end up benefiting or losing depends on a question no one can yet answer: what is a company that lands rockets and aspires to colonise Mars actually worth?
Three private giants — SpaceX, OpenAI and Anthropic — are about to crash onto Wall Street under a brand-new rulebook that could turn one company's IPO into the most disruptive index event in modern history.
SpaceX is preparing what's expected to be the largest IPO ever, with OpenAI filing paperwork as soon as this week and Anthropic close behind. Nasdaq just rewrote a key rule so that giant new listings can join the Nasdaq 100 index after only 15 trading days — down from a roughly three-to-twelve-month waiting period.
Because trillions of dollars sit in passive funds that mechanically copy that index, the rule change forces those funds to buy the new stocks almost immediately. To make room, the same funds have to sell other tech stocks already in the index. JPMorgan estimates that if half of SpaceX's shares eventually float at a $2tn valuation, passive investors would need to dump roughly $95bn of Wall Street's eight biggest existing tech stocks.
Index funds aren't really 'investors' in the picking-winners sense — they're rule-followers. When the rulebook changes, they don't think, they just trade. The interesting question is who benefits and who gets squeezed.
If your parents own an S&P 500 or Nasdaq 100 fund inside a 401(k) or ISA — and most working adults do — they're about to become involuntary SpaceX shareholders at whatever price the market sets in the first two weeks. Todd Sohn of Strategas put it bluntly: if SpaceX is up 100% the week after the IPO, passive funds 'have to buy it… They can't discriminate.' That mechanical demand affects retirement balances, college-savings accounts and the broader AI bubble debate you'll hear about for the next decade.
This is the moment passive investing — long sold as a boring, neutral way to own 'the market' — collides with an era of giant, founder-controlled private companies finally going public. Expect louder debate about whether index rules should bend for individual listings, more scrutiny of dual-class voting structures, and a wave of copycat behaviour from NYSE. The second-order effect to watch: if the SpaceX trade goes badly, regulators may force longer seasoning periods back into the rulebook — and the next AI mega-IPO could look very different.