Polymarket is giving OpenAI just a 16% chance of completing an IPO by the end of 2026.
Anthropic, on the same basic question, trades at 91.5%.
OpenAI’s market is structured as a series of date contracts. Each resolves to Yes if the company completes an IPO on a recognized exchange by the deadline. August 31 is now below 1%, September 30 trades around 1.2%, and December 31 sits at 16%.
With the first two deadlines effectively dead, almost all of the market’s remaining 2026 probability is now concentrated in the fourth quarter.
At the end of June, the December contract was around 23.5%. It briefly recovered to 22% in mid-August before falling back into the mid-teens.
That move reflects a growing belief that OpenAI does not need to rush into the public markets this year.
OpenAI IPO Launch Date Urgency
OpenAI confidentially filed its S-1 in June, so the company has already taken one of the major steps toward an IPO.
But it also completed a roughly $7 billion employee tender in August at an $852 billion valuation.
That matters because one of the biggest reasons late-stage private companies eventually go public is liquidity. Employees and early investors are sitting on valuable shares but need an event that allows them to turn some of that paper wealth into cash.
The tender accomplished part of that without requiring an IPO.
It does not eliminate the reason to go public, but it reduces the pressure to do it immediately.
The bigger signal came from CFO Sarah Friar, who reportedly told employees on August 19 that OpenAI expects to be public in 2027, while leaving open the possibility of moving sooner if growth remains strong.
Polymarket moved lower almost immediately.
That is why the 16% December probability feels much more like a bet on timing than a bet on OpenAI’s readiness to be a public company.
The Valuation Matters Too
There is also a large number hanging over the process. OpenAI has previously been discussed as a potential $1 trillion IPO candidate, while the August tender valued the company around $852 billion.
That leaves a meaningful gap between its latest private-market valuation and the type of price investors may expect from a public offering.
Recent IPO performance also gives OpenAI a reason to be patient. A company at this scale does not need to go public simply because the window is open. It can wait for a market environment where it has more confidence in the valuation it will receive. That makes a 2027 listing easier to understand.
Anthropic Shows How Different The Timelines Are
Polymarket gives Anthropic a 91.5% chance of going public by December 31, with earlier deadlines also trading aggressively. Its October 31 contract is around 82.5%. So the market is not broadly skeptical about AI IPOs.
It is specifically skeptical that OpenAI will move this year. That distinction is important. Two of the largest private AI companies can both be headed toward the public markets while still operating on very different timelines. Anthropic looks like a 2026 IPO story.
OpenAI increasingly looks like a 2027 story.
The Rest Of The OpenAI Market Still Expects A Huge Ipo
Interestingly, traders are much more confident about the size of an eventual OpenAI listing than they are about the date.
The market on OpenAI reaching at least a $1 trillion valuation at its IPO trades far above the probability of a 2026 listing, and more than $1 million has already traded in that valuation contract.
So traders are not betting against OpenAI. They are betting against the calendar.
That is probably the cleanest way to understand the entire board: the market still expects OpenAI to become a very large public company, just not necessarily in the next four months.
The Trade
The contract I find most interesting is No on an OpenAI IPO by December 31 at around 84¢.
The basic case is straightforward. OpenAI’s CFO has already pointed toward 2027; the company just provided billions of dollars of private liquidity to employees, and a 2026 IPO now has a fairly tight timeline.
A public S-1 would be the major signal that changes that view. Once the filing becomes public, a company still has to work through investor marketing, regulatory review, and the actual pricing process. A normal IPO roadshow can take several weeks, so the longer OpenAI waits, the harder it becomes to fit the entire process into 2026.
That makes roughly mid-October an important line in the sand. If a public filing appears before then, the December contract could reprice quickly. If October ends without one, the probability of a 2026 listing should fall sharply.
At 84¢, the upside is not enormous; you are risking 84 cents to make 16, but the current timeline favors the No side.
