Wall Street braces for mega-IPOs from Anthropic, SpaceX and OpenAI

Three of the most valuable private companies in the world — Anthropic, SpaceX and OpenAI — are edging toward public markets at valuations that would dwarf almost every recent listing. Their combined worth runs into the trillions, raising the question of whether public investors have the appetite, and the index weight, to absorb offerings of this scale without distorting the broader market.

The arithmetic is daunting. Even a partial float at current private valuations would rival or exceed the largest IPOs in history, and index funds would be forced to take outsized positions in companies whose revenue, in the case of the AI players, is still a small fraction of their paper value. SpaceX, with established cash flows from Starlink and launch contracts, looks more conventional, but its concentrated ownership and dual-class structure complicate the picture.

The deeper concern is reflexivity: if these listings succeed, they cement a generation of AI and space infrastructure bets at prices set by a narrow group of private investors. If they stumble, the shock could ripple through the venture ecosystem that has been propping up valuations on the assumption that an exit at these levels is realistic.