What SpaceX and OpenAI IPOs Mean for Markets

Tom Tunguz runs the math on what happens when SpaceX, OpenAI, and Anthropic all try to go public in the same window, and the numbers don’t work cleanly. At standard 15-20% float levels, the three companies would need $432 to $576 billion from public markets in a single quarter — more than the entire US IPO market raised across the last decade. That forces minimal floats of 3-8%, which then creates a different problem: none of them qualify for S&P 500 inclusion until they expand their float, and when they eventually do, passive funds managing $20 trillion have to buy in by selling existing mega-cap positions. The second-order pressure on incumbent tech stocks from index rebalancing alone could be significant. Nobody has stress-tested public markets against three concurrent trillion-scale listings before.