Anthropic IPO: Polymarket is banking on a listing in October

On June 1, 2026, Anthropic formalized the confidential filing of its IPO file in the United States. Since then, betting has accelerated. As of August 17, Polymarket estimates the probability of a listing before October 31 at 69.5% and that of an arrival on the stock market before the end of the year at 87%. However, no official date has yet been communicated.

October is essential in betting, not in the calendar

After the $9.1 billion mega-deal signed with Riot, Anthropic is now preparing one of the most closely watched financial operations in the AI ​​sector. The laboratory confirmed on June 1 that it had confidentially filed its IPO file in the United States.

The process is therefore well underway. But for the moment, Anthropic has not announced a listing date, price range or amount sought.

It is precisely this void that Polymarket is trying to fill. In the capture relayed by CryptoPotatothe probabilities reached 2% before September 15, 10% before September 30, 70% before October 31 and 83% before December 31.

A consultation of thePolymarket Public APIcarried out on August 17 at 10:31 UTC, gave very close figures: 1.65%, 10%, 69.5% and 87%.

However, one detail is essential. The contract is only validated if Anthropic shares are actually listed and open for trading before the scheduled date. Confidential filing alone is therefore not enough.

The bets are clearly focused on October. Between the deadline of September 30, estimated at 10%, and that of October 31, at 69.5%, the difference reaches 59.5 points. In other words, it is especially the month of October that traders seem to be targeting.

At the time of consultation, the market had approximately $1.54 million in cumulative volume, $35,345 traded over 24 hours, and almost $79,000 in liquidity. Interesting figures to measure contract activity, but which do not necessarily represent the opinion of large institutional investors.

Figures that fuel expectations

The financial file explains why investors are already looking beyond the current year, without validating an IPO valuation. On May 28, Anthropic announced a $65 billion Series H raisefor a post-money valuation of $965 billion.

In the same statement, the company said its annualized revenue crossed $47 billion in early May. Reuters reports for its part a 2028 revenue projection of between $190 and $200 billionattributed to two people familiar with Anthropic’s finances.

The division gives an order of magnitude of 4.0 to 4.3 times the current pace, but compares an annualized pace communicated by the company to a projection that is not published in an accessible S-1.

This extrapolation explains the valuation method observed by Reuters: bankers and investors use revenue multiples based on forecasts. The calculation remains demanding, because Anthropic must finance processors, model training, inference and recruitment before demonstrating that its margins will improve with scale.

Caution also applies to the market signal. A Stanford study on the risk of Polymarket manipulation documented by Tremplin.io involved very short-duration Bitcoin contracts and does not prove Anthropic market manipulation. It nevertheless reminds us that a contract price remains situated information, dependent on its liquidity and its rules.

The real signal will come from the prospectus

No verified source currently sets a firm public date, price range or offer size. There Reuters report published June 1 specifies that Anthropic had not communicated the conditions of the operation, despite the announcement of the confidential filing.

This confidentiality gives the company the opportunity to prepare its transaction while protecting its financial information from competitors and the public. It also leaves the door open to a delay if the regulatory review, the markets or revenue projections no longer justify a listing in the fall.

The next test will therefore be documentary: a public prospectus, a price range or a dated announcement from Anthropic will weigh more than a new Polymarket capture. Meanwhile, 69.5% only means that the “before October 31” contract was trading at that level at the observed time, not that the IPO is decided.

The market places October at the center of the scenario, while Anthropic’s private figures fuel the ambition of an extraordinary operation. What follows should be read with the same caution as the recent tensions at OpenAI: the public filing and financial conditions will be the evidence, the probabilities will remain an indicator of sentiment.