Anthropic IPO odds are the closest thing to a listing date that anyone has right now.
As of September 16, 2026, Polymarket traders price an October listing at roughly a coin flip and a 2026 listing in the mid-80s, while Kalshi's traders, who are pricing an earlier milestone, sit higher.
Anthropic has confirmed none of it.
Key Takeaways
Polymarket traders price an Anthropic listing in October 2026 at about 56% and a listing by December 31 at about 85%, as of mid-September 2026.
Kalshi's ladder reads higher, at about 73% before November 1, because it settles on IPO confirmation rather than on shares trading.
Polymarket's timing markets pay out only when shares actually open for trading, so a filing or an announced date settles nothing.
Anthropic has confirmed one thing about the process: a confidential draft Form S-1 submitted on June 1, 2026.
There is still no public prospectus, ticker, exchange, listing date or price range.
Traders put Anthropic's first-day closing market cap above $600 billion at about 96%, with the leading brackets between $1.75 trillion and $2.5 trillion.
Traders price an Anthropic listing as very likely before the end of 2026, and most likely in October.
The Polymarket figures below were read from the market pages in mid-September 2026, and the Kalshi figures come from published reads of its ladder on the dates shown.
Every one of them moves daily, so treat the dates as part of the data.
Which month: October 2026 leads at about 56%, November at about 21%, December at about 9% (Polymarket, September 16, 2026).
Listed by a date: about 62% by October 31, about 78% by November 30, about 85% by December 31 (Polymarket, September 15, 2026).
Anthropic or OpenAI first: Anthropic in the mid-90s on both venues (September 13 to 15, 2026).
First-day market cap: above $600 billion at about 96%, with the leading bracket of $2.25 trillion to $2.5 trillion at about 23% (Polymarket, September 7 and 14, 2026).
Polymarket does not run one Anthropic IPO market.
It runs several, and they ask genuinely different questions, which is why two people can quote very different numbers for the same company.
The month market asks which calendar month Anthropic lists in, with about $220,000 traded as of September 16, 2026.
The date ladder asks whether Anthropic will be trading by a given cutoff, and it is the deepest of the Anthropic IPO timing markets with roughly $3.1 million traded since it opened on June 1, 2026.
Both settle on the same real-world moment: the first day Anthropic shares are listed and open for regular-way trading.
A separate set of markets asks what Anthropic will be worth at the closing bell on its first day, calculated as shares outstanding multiplied by the first-day closing price.
The broadest version priced a close above $600 billion at about 96% as of September 7, 2026.
The finer brackets cluster between $1.75 trillion and $2.5 trillion, with $2.25 trillion to $2.5 trillion narrowly in front.
One popular Anthropic market asks whether the company's valuation will hit a given level by December 31, with the "above $1.5 trillion" outcome sitting in the mid-90s.
That one resolves on a valuation threshold by a calendar date, not on the listing.
Quoting it as an IPO number is an easy mistake to make, and it inflates what traders are actually saying about the listing.
Kalshi asks when Anthropic will officially announce an IPO, not when its shares start trading.
Its ladder of contracts, listed under the series code KXIPOANTHROPIC-DATE, had traded roughly $2 million as of early September 2026.
Each contract settles if any one of three things happens before its date: the SEC declares Anthropic's registration statement effective, the offering is priced, or an exchange assigns Anthropic a ticker.
That wording matters more than it looks.
The jump from about 3% before October 1 to about 73% before November 1 puts nearly all of the probability inside the single month of October.
Because they are not pricing the same event.
Kalshi prices confirmation before November 1 at about 73%.
Polymarket prices actual trading by October 31 at about 62%.
The reads are days apart, but the main reason for the gap is the resolution rule rather than a disagreement about Anthropic.
The same pattern repeats a month later, with Kalshi at about 91% before December 1 and Polymarket at about 78% by November 30.
Confirmation comes before the opening bell, so on the same calendar the venue that pays on confirmation will read higher.
No, and this is the step where the headlines get ahead of the paperwork.
Going public runs through five steps, and Anthropic has completed exactly one of them.
Step 1, done: a confidential draft Form S-1 submitted to the SEC on June 1, 2026.
Step 3: the SEC declares the registration statement effective.
Step 4: the offering is priced, which sets the share count and the offer price.
Step 5: shares open for trading.
Polymarket's own rules state plainly that announcements, filings and scheduled dates do not settle its timing markets.
Kalshi's contracts settle around steps 3 and 4.
So if you want to know whether this is really happening in October, watch for the public prospectus rather than the headlines.
A contract priced at 56 cents implies a 56% chance.
Winning shares settle at $1.00 and losing shares settle at zero, which is what makes the price readable as a probability at all.
There is friction in that number.
On the October contract, buying Yes and buying No cost slightly more than a dollar combined, and that difference is the spread you pay to take a side.
Volume matters even more.
The October contract has traded about $57,000, while the distant 2027 months have traded roughly $6,000 to $7,500 each.
The direction of travel has been later, not sooner.
By September 8 it was down to about 3%.
Polymarket's October contract printed 61% on September 14 and about 56% two days later.
As of mid-September 2026, no public prospectus had appeared, and the odds had drifted later along with it.
Very little, and the gap between what is confirmed and what is reported is the most useful thing a reader can hold onto.
As of mid-September 2026, no public Anthropic prospectus appears in the SEC's public EDGAR database.
There is no confirmed ticker, exchange, listing date or price range.
Polymarket even runs a market on what the ticker will be, currently favoring $ANTH, which tells you everything about how unsettled this is.
Reasonably, in aggregate, and they are weakest at exactly this kind of question.
In a 2006 paper, economists Justin Wolfers and Eric Zitzewitz set out the conditions under which a contract price lines up with traders' average belief, and concluded that prices give useful, if sometimes biased, estimates of it. Now the caveat.
Elections are repeated events with enormous samples.
One company's listing date is a single novel event, and some of these contracts trade on a few thousand dollars, which is a much weaker setting for any one number on the board.
Read the odds as sentiment with money behind it, not as a schedule.
No, and the three routes people confuse are worth separating clearly.
An event contract pays a fixed amount if an outcome happens, so you are trading a probability rather than a company.
MEXC Prediction Markets works on the same binary logic, where a Yes price of 0.65 reflects a roughly 65% market view and holders of the correct side are paid on settlement. A pre-IPO perpetual is a different instrument again.
Its mark price references a pre-listing composite index rather than a live stock price, so it is not a claim on the offering.
Actual Anthropic shares are the third route, and that one does not exist for retail buyers until the listing is done.
Daily, and the October contract moved about five points in the 48 hours before this snapshot.
The snapshot in this article is dated for that reason, and the figures are refreshed weekly.
If you are tracking this seriously, the numbers to re-check are the October contract and the year-end cutoff.
What are the current Polymarket odds for an Anthropic IPO?
About 56% for a listing in October 2026 and about 85% for a listing by December 31, as of mid-September 2026.
Is Anthropic publicly traded yet?
No, Anthropic remains a private company with no shares available on any public exchange.
What is Anthropic's stock ticker symbol?
There is no confirmed ticker, and any symbol you see quoted is speculation until an exchange assigns one.
Does a confidential S-1 filing settle these markets?
No, Polymarket's timing markets require shares to actually open for trading, while Kalshi's settle on SEC effectiveness, pricing or ticker assignment.
Will Anthropic or OpenAI go public first?
Traders on both venues put Anthropic first, pricing it in the mid-90s.
What does a price of 56 cents mean?
It means the market implies a 56% chance of that outcome, with winning shares settling at $1.00.
Are these odds a forecast of Anthropic's IPO date?
No, they are a live reading of trader sentiment that changes daily and has no official standing.
The honest summary is that traders are confident about the year and only half-confident about the month.
That is still more information than a headline gives you, as long as you read the resolution rules before you read the percentage.
If you want to trade probabilities rather than guess at them, MEXC Prediction Markets applies the same mechanics to events you can follow week to week.
Odds in this article were read from the Polymarket and Kalshi market pages on the dates shown and are refreshed weekly, with Anthropic's filing facts taken from the company's own June 1, 2026 announcement and the SEC's public EDGAR database.