What does the Anthropic IPO market resolve on?

It resolves Yes if Anthropic shares are listed on a public securities exchange and open for trading by 11:59 PM ET on the stated date. If Anthropic is instead acquired by a company that is already public, the market resolves No immediately. The resolution sources are official filings and announcements from Anthropic and the exchange, including Form S-1 and Form 8-A, with credible reporting used as a fallback.

Has SpaceX already had its IPO?

Yes. SpaceX listed on the Nasdaq on 12 June 2026, raising about 75 billion dollars at a 1.77 trillion dollar valuation, and closed its first trading day at a market capitalisation of roughly 2.1 trillion. That matters for the largest-IPO-of-2026 market, because it means SpaceX is a settled benchmark rather than a future event, and Anthropic has to close above it on day one to win.

Why do the bucket prices add up to more than 100%?

Every market on a multi-outcome board is quoted independently, and each quote carries a spread, so the sum of the mid prices sits above one. The Anthropic valuation ladder sums to about 105.5% as of 8 September 2026. If you add several rungs to get the probability of a range, divide by that total, otherwise you will overstate the odds by roughly five points and misprice the trade.

What happens to the first-to-list market if neither company goes public?

It resolves 50-50, meaning each side pays 50 cents rather than one side paying a dollar. The market runs to 31 December 2027 and that clause also applies if both list on the same calendar date. It changes the arithmetic on the OpenAI side considerably: at 3.55 cents it returns roughly 28x if OpenAI genuinely lists first, but it also returns about 14x in the world where neither company makes it to market by the end of 2027.

Can I buy Anthropic shares before the IPO?

No. Anthropic is a private company and its shares are not available to retail buyers before a listing. Prediction markets are not a way around that either — buying a contract on these boards gives you exposure to whether an event happens, not equity in the company, no ownership, no voting rights and no claim on the share price after listing.

Is the October date confirmed?

No. Reporting from August 2026 said investors were targeting an October listing at around a 2 trillion dollar valuation, but that figure came from backers rather than the company, and reports noted senior executives had not set a valuation target. The market prices October at 58.5%, which is a long way from certainty, and a confirmed date announcement would move every board discussed here at once.

ANALYSIS

Anthropic IPO odds on four prediction markets

September 8, 2026 · 9 MIN READ

Four separate markets price the Anthropic listing: when it happens, who lists first, whether it is the year's largest, and what it closes at on day one. They are not four views of the same question, and the most interesting number on the board comes from reading two of them against each other.

Key takeaways

The market prices an Anthropic listing by 31 December 2026 at 88.5% and by 31 October at 55.5%, while the month-by-month board puts October alone at 58.5% and November at 24.2%.
The largest-IPO market is not a question about whether SpaceX lists — SpaceX already listed on 12 June 2026 and closed its first day near 2.1 trillion dollars, which is the bar Anthropic has to clear.
The largest-IPO market and the valuation ladder both resolve on first-day closing market cap, so they check each other: the ladder implies 63% above 2 trillion, the largest-IPO board pays Anthropic 58.7%.
The valuation ladder's ten rungs sum to 105.5%, so adding raw bucket prices overstates any combined probability by about five points unless you normalise.
The Anthropic-or-OpenAI-first market runs to 31 December 2027 and resolves 50-50 if neither company lists, so buying the OpenAI side at 3.55c is not a clean bet on OpenAI winning the race.

Anthropic confidentially submitted a draft Form S-1 to the SEC on 1 June 2026, and OpenAI confirmed its own confidential submission a week later on 8 June. Neither company's shares can be bought before a listing, but four separate boards let you price the event itself — and they are asking genuinely different questions.

All prices are from Polymarket and Oddzy data on 8 September 2026 and move daily. Market analysis, not investment advice, and nothing here relies on non-public information.

The boards this is priced from

Open the IPO markets →

All four markets below, plus the month-by-month timing ladder, are now on Oddzy under Economy → IPOs.

When does the market think Anthropic lists?

The date ladder prices a listing by 31 December 2026 at 88.5% and by 31 October at 55.5%, on about $2.66M of event volume. The rungs are nested — a listing by October is also a listing by December — so the ladder prices when, not whether.

Deadline	Yes	What it implies
By 15 September	0.05%	effectively ruled out
By 30 September	0.65%	ruled out
By 15 October	9.5%	early-October listing
By 31 October	55.5%	the coin-flip rung
By 30 November	83.5%
By 31 December	88.5%	the headline number

The separate month-by-month board is the sharper read, because its buckets are exclusive rather than cumulative: October 58.5%, November 24.2%, December 4.2%, and 1.25% on no listing before 2028. That is a market with a firm view on October and a real tail into November.

Buying Yes on the December rung at 88.5c returns about 13% if the listing lands this year. The No side at 11.5c returns 8.7x and is purely a bet on slippage into 2027 — which is why the October rungs matter more than the December one. Most of the disagreement worth trading is in the timing, not the outcome.

Who lists first, Anthropic or OpenAI?

This board prices Anthropic at 96.45c and OpenAI at 3.55c, on $337k of volume, and the pricing is not really a mystery: OpenAI's CFO said in August that the company "will be a public company in 2027," or sooner if the business inflects. The separate board on an OpenAI listing by 31 December 2026 sits at just 7%.

The part worth reading twice is in the resolution text. The market runs to 31 December 2027 and resolves 50-50 if neither company lists by then — and also if both list on the same calendar date. So the OpenAI side is not a clean short on Anthropic:

OpenAI genuinely lists first → 3.55c pays 100c, about 28x.
Neither lists by end-2027 → 3.55c pays 50c, about 14x.
Anthropic lists first → zero.

That second line is the one people miss. It does not make the OpenAI side cheap, but it means you are buying two paths, not one, and the "everything slips badly" scenario is not a total loss. The Anthropic side at 96.45c returns 3.7% and is a place to park conviction, not a trade.

Is the largest-IPO market actually about SpaceX?

Not in the way it looks. SpaceX has already listed — it went public on the Nasdaq on 12 June 2026, raised about $75B at a $1.77T valuation, and closed its first trading day near $2.1 trillion. So this board is not asking whether SpaceX will come to market this year. It is asking whether Anthropic closes its first day above the number SpaceX already set.

Company	Price	Volume
Anthropic	58.7c	$1.09M
SpaceX	37.5c	$872k
OpenAI	1.75c	$545k

Two cautions on this board. The event resolves on first-day closing market cap, defined as shares outstanding times the closing price — not the offer price, not the opening pop. And the xAI rung quotes 25.5c on zero volume, which is a stale book rather than a real probability; it is why the outcomes sum to more than 100%. Ignore it and the remaining names sum to a sane 98.4%.

What does the market think it closes at?

The valuation ladder prices the first-day close in $250B brackets. Anthropic's last private round put it at $965B post-money, and this board sits far above that:

Closing market cap	Probability
Under $1.25T	0.45%
$1.25–1.5T	2.05%
$1.5–1.75T	10.95%
$1.75–2.0T	25.5%
$2.0–2.25T	22.85%
$2.25–2.5T	18.5%
$2.5–2.75T	12.45%
$2.75–3.0T	4.9%
Above $3.0T	7.7%
No IPO by end-2027	0.15%

These ten rungs sum to 105.5%, not 100%. Each is quoted independently with its own spread, so adding raw prices overstates any combined probability by about five points. Normalise before you act on a range: raw, the rungs above $2T total 66.4%; normalised, about 63%.

Where the two boards check each other

This is the most useful thing on the page, and it only works because both markets resolve on the same quantity — first-day closing market cap.

The valuation ladder implies roughly 63% that Anthropic closes above $2.0T.
The largest-IPO market pays Anthropic 58.7% to close above SpaceX's ~$2.1T.

Those two numbers should not be identical, and they aren't: the second bar is higher, so it should price lower, and it does, by about four points. The boards agree. That is worth knowing before you treat either one as mispriced — if you think 58.7c on Anthropic is cheap, you are also implicitly saying the valuation ladder is wrong, and you should be able to say why.

The corollary is the trade the draft version of this analysis got wrong: buying Anthropic at 58.7c is not a bet that "SpaceX doesn't list this year." It is a bet on a first-day close above roughly $2.1 trillion, which is a valuation question, not a calendar one.

How would you actually take a view?

"The hype is overdone." The rungs below $2.0T sum to 38.95c raw and return about 2.6x if the close lands under two trillion. That is the cleanest expression of a sceptical view, and it does not require you to doubt the listing happens at all.
"It breaks the record convincingly." The $2.25–2.5T rung at 18.5c returns about 5.4x. Narrower, and it needs day-one enthusiasm to land in a specific $250B window.
"It slips to 2027." No on the December rung at 11.5c returns 8.7x, and the month board's 24.2% on November tells you how much of the slippage risk is only weeks, not quarters.

Three practical points. These boards are correlated — the date ladder, the first-to-list market and the largest-IPO market are all hostages to the same event, so positions across several of them are one bet placed repeatedly; size the whole cluster, not each leg. The ladder rungs are thinner than the headline markets, at $30–95k each against $1M on the largest-IPO board, so use limit orders and read the ask. And a confirmed date announcement repriced all four boards simultaneously — take the position before the announcement or not at all.

Finally, read the resolution text on the specific rung you are buying. The difference between offer price, opening price and first-day close is the difference between three different answers on this board, and that is where these markets are won and lost.

Common questions

What does the Anthropic IPO market resolve on?: It resolves Yes if Anthropic shares are listed on a public securities exchange and open for trading by 11:59 PM ET on the stated date. If Anthropic is instead acquired by a company that is already public, the market resolves No immediately. The resolution sources are official filings and announcements from Anthropic and the exchange, including Form S-1 and Form 8-A, with credible reporting used as a fallback.
Has SpaceX already had its IPO?: Yes. SpaceX listed on the Nasdaq on 12 June 2026, raising about 75 billion dollars at a 1.77 trillion dollar valuation, and closed its first trading day at a market capitalisation of roughly 2.1 trillion. That matters for the largest-IPO-of-2026 market, because it means SpaceX is a settled benchmark rather than a future event, and Anthropic has to close above it on day one to win.
Why do the bucket prices add up to more than 100%?: Every market on a multi-outcome board is quoted independently, and each quote carries a spread, so the sum of the mid prices sits above one. The Anthropic valuation ladder sums to about 105.5% as of 8 September 2026. If you add several rungs to get the probability of a range, divide by that total, otherwise you will overstate the odds by roughly five points and misprice the trade.
What happens to the first-to-list market if neither company goes public?: It resolves 50-50, meaning each side pays 50 cents rather than one side paying a dollar. The market runs to 31 December 2027 and that clause also applies if both list on the same calendar date. It changes the arithmetic on the OpenAI side considerably: at 3.55 cents it returns roughly 28x if OpenAI genuinely lists first, but it also returns about 14x in the world where neither company makes it to market by the end of 2027.
Can I buy Anthropic shares before the IPO?: No. Anthropic is a private company and its shares are not available to retail buyers before a listing. Prediction markets are not a way around that either — buying a contract on these boards gives you exposure to whether an event happens, not equity in the company, no ownership, no voting rights and no claim on the share price after listing.
Is the October date confirmed?: No. Reporting from August 2026 said investors were targeting an October listing at around a 2 trillion dollar valuation, but that figure came from backers rather than the company, and reports noted senior executives had not set a valuation target. The market prices October at 58.5%, which is a long way from certainty, and a confirmed date announcement would move every board discussed here at once.