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Anthropic or OpenAI: higher IPO closing market cap odds

Polymarket traders put the chance of Anthropic at 76% and OpenAI at 24% for “Anthropic or OpenAI: higher IPO closing market cap” (Anthropic unchanged in the last 24 hours).

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Prices refresh every few minutes. Probabilities are not predictions or advice, and you can lose what you trade.

Chance of Anthropic over the last 30 days

Price of a Anthropic share.

Sep 26Oct 26

Anthropic and OpenAI odds

Probability is the share price. Decimal odds show what $1 returns if that outcome wins, before fees. American odds show the same price as a moneyline: +150 pays $150 on a $100 stake, −200 needs $200 to win $100.

Odds as of

Where this market stands

“Anthropic or OpenAI: higher IPO closing market cap” is a Polymarket market with two outcomes. Anthropic is priced at 76% and OpenAI at 24%; Anthropic is unchanged over the last 24 hours and up 7.5 points over the past week. Traders have put $334 through the market so far, including $0 in the last 24 hours, and it is scheduled to end on January 1, 2029.

Whale trades in this market

The latest trades of $1,000 or more on this event, newest first.

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How this market resolves

This market will resolve to "Anthropic" if the official closing price for Anthropic's market capitalization on its first trading day is above the official closing price for OpenAI's market capitalization on its first trading day.

This market will resolve to "OpenAI" if the official closing price for OpenAI's market capitalization on its first trading day is above the official closing price for Anthropic's market capitalization on its first trading day.

This market will resolve to the company that completes an Initial Public Offering (IPO) by December 31, 2028, 11:59 PM ET, if the other company does not complete an IPO within the market timeframe. This market will resolve to the IPOed company as soon as it becomes impossible for the other company to complete an IPO within the market timeframe, including due to acquisition, merger, or absorption by an entity that is already publicly traded.

This market will resolve 50-50 if:

- Neither IPO occurs by December 31, 2028, 11:59 PM ET.

- Both Anthropic and OpenAI complete an IPO within this market's timeframe, and their IPO closing market capitalizations are exactly equal.

- Both companies become unable to complete an IPO, including due to acquisition, merger, or absorption by an entity that is already publicly traded.

Market capitalization expresses the monetary value of a company’s outstanding shares, stated in its pricing currency.

It is calculated as the total number of outstanding shares, multiplied by the official closing share price of the publicly traded class on the first trading day.

If necessary, to accurately capture the company’s total market capitalization, rather than a stock-class-specific market capitalization, the calculation will include all outstanding share classes and apply any stated conversion ratios to the publicly traded class. Where no conversion right exists, such shares will be counted at their stated outstanding amount without discount, unless official filings explicitly specify differently.

The number of outstanding shares will be determined from official company filings or disclosures (e.g., SEC filings). The closing share price on the first trading day will be determined from the primary exchange’s official listing page.

In the event of an interruption in the normal trading session on the specified company’s first day of trading (e.g., a circuit breaker or half-day), the market will resolve according to the official closing price of the abbreviated session. If no such official closing price is published, the market will resolve according to the next trading day on which an official closing price is published, treating that day as the first day of trading for the purposes of this market.

Rules are written by Polymarket and shown as published. WhaleSays does not settle markets.

Common questions

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Anthropic or OpenAI: higher IPO closing market cap?
Polymarket currently prices Anthropic at 76% (decimal odds 1.32, American −317) and OpenAI at 24% (decimal odds 4.17, American +317). Each price is the market's implied probability for that outcome.
When does this market close?
The listed end date is January 1, 2029. Read the resolution rules on this page to see what counts and who decides.

Related odds

Anthropic IPO Closing Market Cap

  • $1.75–$2.0T30%
  • $2.0–$2.25T21%
  • $1.5–$1.75T20%

$2.4M traded · $117K in 24h

What will Anthropic's IPO valuation be?

  • $1.50–$1.75T62%
  • $1.75–$2.00T19%
  • $2.00–$2.25T4%

$226K traded · $12K in 24h

Will Anthropic’s valuation hit __ by December 31?

  • ↑$1.5T87%
  • ↑$1.75T79%
  • ↑$2.0T60%

$6.1M traded · $25K in 24h