Selected ranges are below $500 billion and $500–750 billion at the first trading day's close. A contract does not establish that an IPO will occur. The full event has a separate outcome for no IPO by the end of 2027.
Will OpenAI’s market cap be less than $500B at market close on IPO day by December 31, 2027?
Market estimate / Yes
2.5%
7 days+0.2 pp
30 days+1.9 pp
Price basis: Bid/ask midpoint
Probability history
Recorded source observations · CLOB price historyOct 9, 2026 — Oct 16, 2026
This number reflects a source price. It is not a certainty, a personal forecast or an executable offer.
CONTRACTS
Outcomes
These contracts ask separate questions. Their probabilities must not be added together.
Will OpenAI’s market cap be less than $500B at market close on IPO day by December 31, 2027?
Yes2.5%Bid/ask midpoint
No97.5%Bid/ask midpoint
Contract deadline · per API: Jan 1, 2028, 04:59:00 AM UTC
Market cap is outstanding shares multiplied by the official first-day closing price. An exact bracket boundary belongs to the higher range. An abbreviated session's official close applies; if none is published, the next day with an official close is treated as the first day. No IPO by 23:59 ET on December 31, 2027 selects the separate no-IPO outcome.
Original source rules (English)
This market will resolve based on OpenAI's market capitalization at the closing price on its first day of trading.
If no IPO occurs by December 31, 2027, 11:59 PM ET, the market will resolve to "No IPO by December 31, 2027".
Market capitalization expresses the monetary value of a company’s outstanding shares, stated in its pricing currency. It is calculated as the number of shares outstanding multiplied by the closing share price on the first trading day.
If the relevant value falls exactly between two brackets, then this market will resolve to the higher range bracket.
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 for purposes of this market.
Will OpenAI’s market cap be between $500B and $750B at market close on IPO day by December 31, 2027?
Yes1.8%Bid/ask midpoint
No98.3%Bid/ask midpoint
Contract deadline · per API: Jan 1, 2028, 04:59:00 AM UTC
Market cap is outstanding shares multiplied by the official first-day closing price. An exact bracket boundary belongs to the higher range. An abbreviated session's official close applies; if none is published, the next day with an official close is treated as the first day. No IPO by 23:59 ET on December 31, 2027 selects the separate no-IPO outcome.
Original source rules (English)
This market will resolve based on OpenAI's market capitalization at the closing price on its first day of trading.
If no IPO occurs by December 31, 2027, 11:59 PM ET, the market will resolve to "No IPO by December 31, 2027".
Market capitalization expresses the monetary value of a company’s outstanding shares, stated in its pricing currency. It is calculated as the number of shares outstanding multiplied by the closing share price on the first trading day.
If the relevant value falls exactly between two brackets, then this market will resolve to the higher range bracket.
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 for purposes of this market.
Editorial summary / translation. Original source rules remain authoritative.
Market cap is outstanding shares multiplied by the official first-day closing price. An exact bracket boundary belongs to the higher range. An abbreviated session's official close applies; if none is published, the next day with an official close is treated as the first day. No IPO by 23:59 ET on December 31, 2027 selects the separate no-IPO outcome.
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