SpaceX, OpenAI and Anthropic IPOs will trigger unprecedented trading activity under new Nasdaq "fast entry" rules. The listings will force billions in passive money into these stocks while requiring investors to sell other holdings. Elon Musk's rocket company filed for what's expected to be the largest IPO on record, hours after OpenAI revealed listing plans and Anthropic signaled profitability.

Under previous rules, SpaceX would have been excluded from indices due to its small "free float" of shares available to public investors. New regulations will allow the company to join the Nasdaq 100 after just 15 days. JPMorgan estimates that if 50% of SpaceX shares float with a $2tn valuation, passive investors must sell $95bn of existing tech stocks.

The initial impact on the index will be limited by SpaceX's small share offering at IPO, though the effect grows after lock-up periods expire. Wall Street braces for massive portfolio realignment as these tech giants enter indices tracked by trillions in passive investments. The rule change creates a new dynamic for how IPOs enter major indices.