OpenAI IPO closing market cap above $800B?
Part of: OpenAI IPO closing market cap above ___ ?. Crowd probability estimates from prediction markets, not financial advice.
Probability history
Gridlines at 25, 50 and 75 percent. History covers the recorded price path of the YES outcome.
Resolution criteria
This market will resolve to “Yes” if the official closing price for OpenAI's market capitalization on its first trading day is above the listed value. Otherwise, it will resolve to “No”. If no IPO occurs by December 31, 2027, 11:59 PM ET, this market will resolve to “No”. Market capitalization is defined as the total number of outstanding shares multiplied by the closing share price on the first trading day. Resolution will be based on the primary exchange’s official listing page. In the event that the relevant figure is not displayed, another reliable source will be used. In the event of an interruption in the course of the normal trading session on OpenAI's first day of trading (e.g., a circuit breaker or half-day), the market will resolve according to the official closing price of the abbreviated session. If no such official closing price is published, the market will resolve according to the next trading day on which an official closing price is published, treating that as the first day of trading.
Source: Polymarket via the public gamma API, synced by Kresmion. Last updated 2026-07-15 00:23 UTC. Trade on the venue itself: this page is research context, not an order book. Percentages are YES prices and can move fast.