OpenAI IPO Closing Market Cap

Resolution Criteria

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, 2026, 11:59 PM ET, the market will resolve to "No IPO by December 31, 2026". 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.

Prediction market trading on OpenAI's IPO closing market capitalisation is broadly distributed across a wide range of valuation brackets, with no single outcome commanding a dominant share of volume. The heaviest-backed single outcome is '1.5T+', followed closely by the 'No IPO by December 31, 2026' outcome, indicating genuine uncertainty about both the timing and the scale of any listing. The market resolves based on OpenAI's official closing market cap on its first trading day, or to 'No IPO' if no listing occurs before 31 December 2026.

Market structure

The market spans seven outcomes: six valuation brackets ranging from below 500 billion to 1.5 trillion and above, plus a 'No IPO by December 31, 2026' fallback. Volume is broadly distributed across the upper brackets and the no-IPO outcome, with no single bracket capturing a commanding share. Resolution uses the primary exchange's official closing price on the first trading day. The deadline is 31 December 2026 at 11:59 PM ET.

Background

OpenAI, the organisation behind the ChatGPT and GPT-4 series of AI models, has operated as a capped-profit structure since 2019 but has been reported as pursuing a transition to a more conventional for-profit corporate structure. That restructuring is widely seen as a prerequisite for any public listing. The company raised capital at private valuations in the hundreds of billions of dollars during 2024 and 2025, placing it among the most valuable private technology companies in history. Public interest in an OpenAI IPO is substantial, given the company's central role in the generative AI boom. However, no formal IPO filing or confirmed timeline had been publicly announced as of mid-2025, and regulatory, structural, and market conditions all remain in flux.

Key factors

Several structural factors bear on whether and at what valuation an OpenAI IPO could resolve this market. First, the completion of OpenAI's reported corporate restructuring — converting from a capped-profit to a standard for-profit entity — is widely characterised as a necessary precondition for a public listing. Any legal or regulatory challenge to that restructuring could delay or prevent an IPO within the resolution window. Second, broader equity market conditions at the time of any listing would influence the closing market cap on the first trading day, independent of OpenAI's fundamental valuation. Third, the competitive landscape in AI — including the performance of rival models, revenue trajectories, and investor appetite for high-multiple technology stocks — shapes how public markets might price the company. Fourth, the resolution criteria treat an interrupted first trading session (such as a circuit breaker) as still valid if an official closing price is published, or defer to the next trading day if not, which could affect the recorded figure in volatile market conditions.

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