OpenAI IPO Closing Market Cap: 500–750B
Leader sits at 8% across 2 bound outcomes, runner-up at 5%. This is a winner-take-all market — the headline is the leader’s price, not an arithmetic mean.
Leader probability
500–750B
Outcomes
2
winner-take-all
Runner-up
5¢
500–750B
Spread
3pp
contested
24h volume
$561
thin orderbook
Closes
Dec 31, 2027
574 days
Venue
Polymarket
2 bound
30-day trend
Bracket family
How the bracket ladder is priced.
Each row is one outcome on the venue. Sorted by 24h volume — the heaviest book is at the top.
Cluster 1
OpenAI IPO Closing Market Cap: 500–750B
OpenAI IPO Closing Market Cap: 500–750B
0x3f9f68…1ed3
OpenAI IPO Closing Market Cap: 500–750B
0x59273d…a09e
Analysis
This probability represents the market's assessment that OpenAI will complete an initial public offering with a closing market capitalization between $500 billion and $750 billion. At 19%, traders view this outcome as unlikely relative to other valuation scenarios. The low probability reflects several crosscurrents: OpenAI's stated preference for remaining private, uncertainty about IPO timing (related contracts price "no IPO by December 31, 2026" at 73%), and disagreement about potential valuation if a listing occurs (other contracts show higher valuations commanding only 11% probability). The main factors keeping this specific band depressed are that market participants appear to favor either no near-term IPO or significantly higher valuations ($1.5T+). Resolution depends primarily on OpenAI's actual IPO announcement and subsequent market performance, though there are no scheduled announcements or fixed deadlines currently driving near-term probability movements.
- ›OpenAI has not announced public IPO plans; 73¢ Polymarket contract pricing "no IPO by end-2026" suggests market expects continued private status through year-end
- ›If an OpenAI IPO occurs, market participants assign only 11% probability to the $1.5T+ valuation band, implying consensus belief in either lower valuations or no listing at $500–750B range
- ›The $500–750B band represents a moderate valuation; higher-strike contracts ($1.6T+) trade at 30¢, indicating meaningful probability mass above this range
- ›Trading volume across OpenAI IPO contracts ($2–2.3K daily) is lower than comparable SpaceX IPO contracts ($2.7–2.5K), suggesting less certainty or conviction among traders
- ›The 19% probability for this specific band depends on conjunction of two events: (1) IPO occurring before or concurrent with 2026 close, and (2) valuation landing in this narrow $250B band rather than above or below
What moved the line
- Jun 1500–750B↑3pp5→8¢ · Polymarket
Recently closed in ai tech
- How many SpaceX launches in May?: 14 or morelast 90% · 3d
- Largest Company end of May?: NVIDIAlast 97% · 4d
- What will NVIDIA (NVDA) hit in May 2026?: ↑ $240last 3% · 5d
- Anthropic valued higher than OpenAI in 2026last 90% · 6d
- Will NVIDIA (NVDA) close above ___ end of April?: $200last 5% · 7d
These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.
Lateral coverage
Thin contract — here's where the deeper coverage is.
This page aggregates 2 contracts (8% headline). At low contract count, the price reflects two participants’ opinions, not a market consensus. The links below are heavier related questions where the orderbook signal is real.
Thicker comparable contracts
In ai tech
Related reading
AI Model Race Intensifies as Anthropic Gains on OpenAI
The AI leadership race is heating up with Anthropic's Claude 5 release expectation jumping 16¢ to 38¢ for a June 30 launch, while OpenAI's GPT-5.6 probability dropped 8¢ to 79¢. Markets now favor Anthropic to have the best AI model by end of June at 84¢. The 'Best AI in Jun' contract trades at 63¢ for Anthropic vs 16¢ for Google.
OpenAI IPO Fading: 'No IPO by 2026' Surges to 66¢
OpenAI's IPO probability continues declining as markets price in long-term privacy, while Databricks emerges as the likely AI bellwether for a potential tech listing window reopening.
How we compute these odds
SimpleFunctions aggregates live prediction-market contracts from Kalshi and Polymarket. Each slug groups contracts that resolve on the same underlying event, identified by venue event_id.
For binary slugs, the headline probability is the liquidity-weighted mid-price across all bound contracts. For multi-outcome slugs (e.g. elections with 3+ candidates), the headline is the leader’s price; we never arithmetically average disjoint outcomes — that would produce a number with no real-world meaning.
Snapshots refresh every 5 minutes during market hours; daily aggregates are computed at 04:00 UTC. The 30-day sparkline is drawn from per-ticker daily means stored in market_indicator_daily; 24h delta and movement events are derived from the same source.
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