Will OpenAI’s market cap be between $1T and $1.25T at market close on IPO day?

Prediction markets put the probability at 21%: Will OpenAI’s market cap be between $1T and $1.25T at market close on IPO day. Currently, markets see this as unlikely (21% YES). That’s because the valuation of just three startups, SpaceX, OpenAI and Anthropic, have exploded over the last year.

What’s Happening

OpenAI is preparing to confidentially file for a U.S. initial public offering in the coming weeks, a source familiar with the matter told Reuters on May 20, 2026, two days after the ChatGPT maker fended off an existential court challenge from Elon Musk. The company was last valued at $852 billion in its most recent private round, leaving a roughly 17% gap to the $1 trillion floor and a 47% gap to the $1.25 trillion ceiling that frames the question of whether openai's market cap be between $1t and $1.25t at market close on ipo day. Confidential filings under the JOBS Act typically precede a public S-1 by 15 to 30 days, with first-day trading following another two-to-four weeks of roadshow pricing. [HuffPost, May 20]

The IPO horse race reordered on May 20 when reports surfaced that OpenAI could file as soon as Friday, displacing Anthropic, valued at $380 billion and reportedly raising another $30 billion, as the favorite to reach public markets first. The reference comp remains SpaceX, tipped to debut on June 12 at a valuation north of $1.5 trillion following its February merger with xAI that valued the combined business at $1.25 trillion. Historical first-day pops in mega-cap tech IPOs have ranged widely: Alibaba closed its 2014 debut at $231 billion, while Facebook opened at roughly $104 billion in 2012 before sliding below issue price within weeks. [CNBC, May 20]

For openai's market cap be between $1t and $1.25t at market close on ipo day to resolve YES, the offering would need to price at a roughly 17-47% premium to the last private mark, a band consistent with recent AI-sector debuts but narrower than the typical first-day variance. Cerebras Systems closed its May 14 debut with a market cap just under $100 billion, demonstrating live appetite for AI-infrastructure equity but also the gap between roadshow targets and closing prints. The $1T-$1.25T window represents only one of several outcome buckets — sub-$1T, $1.25T-$1.5T, and above-$1.5T scenarios each draw probability from late-stage secondary trades and confidential allocation indications, with final pricing dependent on the S-1 disclosure of 2025 revenue run-rate and gross margin. [Forbes, May 14]

Traded on Polymarket — $189K Volume

Polymarket prices this at 15c YES with $189K in volume. Moderate liquidity — use limit orders for positions above $1K to avoid moving the price.