PolymarketTechOpen

OpenAI IPO closing market cap above $1T?

75¢−300

last trade · closes 2028-01-01

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24h volume$1.3K
Open interest$5.8K
Lifetime volume$1.1M

Odds history

Implied odds over timebid/askmid90%78%66%Sep 18 14:04 UTCSep 23 13:52 UTC

How this market settles

hard deadline December 31, 2027

Pays Yes when
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.
Who decides
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.
When
Closes 2028-01-01.
Read the full rules Polymarket publishes

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.

What this bet really costs you

  • On $100 at 75¢ you pay $1.75 in fees on Kalshi

    1.31¢ per contract · 133 contracts

  • On $100 at 75¢ you pay $1.50 in fees on Polymarket US

    1.13¢ per contract · 133 contracts

Exchange-side taker fees per each venue's published formula (rate × contracts × price × (1 − price)); contracts = stake ÷ price, rounded down to whole contracts. Fees peak at 50¢ and shrink toward the extremes. Most quoted cross-venue “arbs” are negative-EV after these fees; the taker-fee breakeven on a Kalshi/Polymarket pair is roughly 3.5–4¢.

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Data: Polymarket id 0x7080086a82babdb1b556ddc543ce616f82764c40c3860002e0ab38396eb8078b · ← All tracked markets