OpenAI IPO Closing Market Cap: how this market works

What you need to know

This market is asking two things at once: will OpenAI go public by end of 2026, and if it does, how much will the whole company be worth when trading closes on that first day? Market capitalization, or 'market cap', is simply the share price multiplied by the total number of shares, giving you one number that represents the company's total value as priced by the stock market on day one. A Yes outcome means OpenAI had an IPO and landed in a specific valuation bracket; a No means no IPO happened in time. The market settles using OpenAI's official closing price on its very first day of trading on whatever stock exchange it lists on. That closing price is multiplied by total shares to get the market cap, which then determines the bracket. If no IPO happens before midnight ET on December 31, 2026, the whole market resolves as 'No IPO by December 31, 2026' regardless of valuation. One edge case worth knowing: if trading is interrupted on day one, the official closing price of that shortened session still counts, or the next full trading day is used if no closing price is published at all. No relevant recent news was provided for this market. The kind of developments worth watching for would be any official announcement from OpenAI about plans to convert to a for-profit structure, filing a registration statement with regulators, or naming underwriting banks, as those steps typically precede a public offering. Two separate things have to happen for most outcomes here: an IPO must actually occur, and the valuation must land in a specific range. OpenAI has a complex structure that has been transitioning toward for-profit status, and that process could face legal, regulatory, or internal delays. Even if an IPO does happen, first-day valuations are genuinely hard to forecast, especially for a high-profile AI company where investor enthusiasm can swing prices dramatically. The market prices this around 84%, reflecting real confidence, but the timeline and valuation remain open questions.

The odds right now

• No IPO by December 31, 2026+2.0 pts (1w)84%
• 1T–1.25T-0.9 pts (1w)7%
• 750B–1T+0.1 pts (1w)5%
• 1.5T+-0.5 pts (1w)2%
• 1.25T–1.5T-0.1 pts (1w)2%
• <500B+0.1 pts (1w)1%
• 500–750B-0.3 pts (1w)0%

Price history

How this resolves

Resolves December 31, 2026

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". Read the full resolution rules on the live market page.

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