TOTAL VOLUME:

$114.5b

24H VOL:

$115,807,555

24H TRANSACTIONS:

1,362,287,844

OPEN INTEREST:

$1,188,566,556

336,771

Markets across

33,711

events

MATCHED EVENTS:

4,629

PLATFORM COVERAGE:

5

Polymarket:

42%

VS.

Kalshi:

58%

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Science and Technology
OpenAI IPO Closing Market Cap
polymarket
kalshi

What will OpenAI's market cap be at IPO closing?

Total volume:
$184,284
Volume 24h:
$8,642
583%
Liquidity:
$73,912
13%
Open interest:
$10,687
0.1%

Information Technology

 - Kalshi

Information Technology - Kalshi

1W

News

Positive

Negative

Neutral

Hover marker for details

Vol.

·

Resolves Jan 11, 2028

Will OpenAI be assigned to Information Technology?

86%chance
Amount

$

Trade on
kalshi

Trade on Kalshi

Join Kalshi and score $25 for your first trade.At 90¢ buys you 111 shares | Odds: 86% Total Payout: $111 | Net Profit: $11 Multiplier: 1.11x | ROI: 11% | APY: 8% 501 days to resolution
You will be redirected to the platform to complete this trade.
Outcome
Trade
Chance %
Price
Spread
Liquidity
Volume
24h
7d
Open Interest
Ends in
Result
kalshi

Information Technology

Trade
86%
Yes 90¢No 14¢
4¢
N/A
$3,815
0.29%
0.74%
$1,418
1y 4mo 2w
active
polymarket

1.5T+

Trade
48%
1%
Yes 47.9¢No 52.2¢
0.1¢
$4,561
$40,066
2%
32%
N/A
1y 4mo
active
polymarket

1T–1.25T

Trade
17%
1%
Yes 16.6¢No 83.5¢
0.1¢
$12,021
$21,710
4%
23%
N/A
1y 4mo
active
polymarket

1.25T–1.5T

Trade
17%
Yes 17¢No 84¢
1¢
$11,503
$12,928
5%
19%
N/A
1y 4mo
active
polymarket

No IPO by December 31, 2027

Trade
16%
Yes 16.4¢No 84.9¢
1.3¢
$4,646
$33,661
13%
35%
N/A
1y 4mo
active
kalshi

Unassigned

Trade
7%
Yes 14¢No 93¢
7¢
N/A
$3,094
0%
0%
$351
1y 4mo 2w
active
polymarket

750B–1T

Trade
6%
Yes 6¢No 95¢
1¢
$19,115
$22,068
2%
81%
N/A
1y 4mo
active
kalshi

Communication Services

Trade
5%
Yes 6¢No 100¢
6¢
N/A
$379
0%
0%
$197
1y 4mo 2w
active
kalshi

Real Estate

Trade
4%
Yes 4¢No 100¢
4¢
N/A
$4,049
0%
0%
$158
1y 4mo 2w
active
kalshi

Health Care

Trade
4%
Yes 4¢No 100¢
4¢
N/A
$2,258
0%
0%
$2,141
1y 4mo 2w
active
kalshi

Materials

Trade
4%
Yes 4¢No 100¢
4¢
N/A
$2,170
0%
0%
$2,147
1y 4mo 2w
active
polymarket

500–750B

Trade
1%
Yes 1.9¢No 99.5¢
1.4¢
$8,607
$16,478
4%
49%
N/A
1y 4mo
active
kalshi

Financials

Trade
1%
Yes 4¢No 100¢
4¢
N/A
$2,239
0%
0%
$135
1y 4mo 2w
active
kalshi

Consumer Discretionary

Trade
1%
Yes 4¢No 100¢
4¢
N/A
$2,076
0%
0%
$41
1y 4mo 2w
active
kalshi

Industrials

Trade
1%
Yes 4¢No 99¢
3¢
N/A
$2,054
0%
0%
$781
1y 4mo 2w
active
kalshi

Consumer Staples

Trade
1%
Yes 4¢No 100¢
4¢
N/A
$1,141
0%
0%
$1,141
1y 4mo 2w
active
kalshi

Energy

Trade
1%
Yes 4¢No 100¢
4¢
N/A
$1,141
0%
0%
$1,141
1y 4mo 2w
active
kalshi

Utilities

Trade
1%
Yes 4¢No 100¢
4¢
N/A
$1,035
0%
0%
$1,035
1y 4mo 2w
active
polymarket

<500B

Trade
0%
Yes 0.2¢No 99.9¢
0.1¢
$13,460
$11,921
6%
39%
N/A
1y 4mo
active
Total markets: 19

Description

This event group tracks whether OpenAI will conduct an initial public offering (IPO) by December 31, 2027, and if so, what its market capitalization will be at the close of its first trading day. Polymarket offers granular market cap brackets, while Kalshi's markets address sector classification post-IPO, creating a fundamental scope divergence between the platforms.

PredictionHero - Resolution Divergence Alerts (RDA)

Divergence Detected

Issue: Polymarket and Kalshi measure incompatible outcomes. Polymarket resolves on IPO closing market cap brackets; Kalshi resolves on S&P 500 sector assignment. These are independent corporate events with no logical overlap.Hero tip: Do not assume these markets are correlated. Polymarket's outcome (market cap at IPO close) is determined by investor demand and share pricing on day one. Kalshi's outcome (sector assignment) is determined by S&P Dow Jones Indices classification rules applied after IPO, which is independent of valuation. Treat them as separate event groups.

Critical divergence points:

  • Polymarket: Resolves on OpenAI's market capitalization at official closing price on first trading day. Eight mutually exclusive brackets plus a no-IPO outcome. Resolution source is the primary exchange's official listing page or a reliable alternative source. Handles trading interruptions (circuit breakers, half-day sessions) by using the abbreviated session's official close or the next trading day's close if no official close is published.
  • Kalshi: Resolves to Yes if OpenAI is assigned to any of eleven S&P 500 sectors (Communication Services, Consumer Discretionary, Consumer Staples, Energy, Financials, Health Care, Industrials, Information Technology, Materials, Real Estate, Utilities) or remains Unassigned. Each sector has its own Yes/No market. Resolution is based on S&P Dow Jones Indices sector classification, not IPO valuation.
Our PredictionHero Resolution Divergence Alerts (RDA) are there to help users identify potential differences across platforms. They do not replace or supersede the official rules and description of any prediction market. Users are solely responsible for reviewing and understanding the applicable rules and resolution criteria before placing any trade or bet. If you notice a potential inconsistency, discrepancy, or error in an alert, please report it to our team so we can review and improve the accuracy of our data.

Polymarket

This market will resolve based on OpenAI's market capitalization at the closing price on its first day of trading. If no IPO occurs by December 31, 2027, 11:59 PM ET, the market will resolve to "No IPO by December 31, 2027". Market capitalization expresses the monetary value of a company’s outstanding shares, stated in its pricing currency. It is calculated as the number of shares outstanding multiplied by the closing share price on the first trading day. If the relevant value falls exactly between two brackets, then this market will resolve to the higher range bracket. Resolution will be based on the primary exchange’s official listing page. In the event that the relevant figure is not displayed, another reliable source will be used. In the event of an interruption in the course of the normal trading session on OpenAI’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 as the first day of trading for purposes of this market.

Kalshi

If OpenAI is assigned to a single S&P 500 sector, the corresponding market resolves to Yes and others resolve to No. If OpenAI is assigned to multiple sectors simultaneously, Yes holders for each attributed sector receive $1 divided by the number of sectors, while No holders for those sectors receive the remainder. This proportional payout structure ensures fair distribution when a company spans multiple sector classifications.

Frequently asked questions

The OpenAI IPO Closing Market Cap dashboard aggregates real-time prediction market data across Polymarket and Kalshi, tracking consensus expectations for OpenAI's market capitalization at IPO close. It displays the probability-weighted odds from both platforms, showing how traders across venues assess the likelihood of different valuation outcomes. The dashboard consolidates trading volume and price movements to reflect the collective market view on where OpenAI will be valued when it goes public, helping traders and analysts monitor sentiment shifts as the event approaches.

Polymarket and Kalshi can show different implied probabilities for the same outcome because of liquidity, fee structure, participant mix, and how each venue defines the contract. Polymarket and Kalshi may show different odds due to variations in liquidity, user demographics, and contract design. Polymarket attracts global retail traders with broader market participation, while Kalshi serves a more regulated, institutional audience. Differences in order book depth, fee structures, and the specific outcome buckets offered on each platform create arbitrage opportunities and temporary price gaps. Additionally, timing lags in information flow and distinct user bases responding to news at different speeds can cause the platforms to diverge until traders exploit the spread.

The OpenAI IPO Closing Market Cap market resolves on Jan 11, 2028. Resolution is determined by the official closing market capitalization of OpenAI on its first day of public trading, calculated as the stock price at market close multiplied by total shares outstanding. The outcome will be verified against authoritative financial data sources and regulatory filings. Traders should monitor SEC filings, IPO pricing announcements, and official exchange data as the resolution date approaches to understand which valuation bracket will ultimately determine the winning outcome.

Key catalysts for OpenAI's IPO valuation include product launches, competitive announcements from rivals like Google and Anthropic, regulatory developments around AI governance, and macroeconomic shifts affecting tech valuations. Earnings or funding announcements, leadership changes, and geopolitical tensions affecting AI policy could significantly move market expectations. Additionally, broader market conditions, venture capital sentiment, and comparable IPO performance will influence trader positioning. Major AI breakthroughs or safety concerns could also shift the perceived risk profile and justify higher or lower valuations heading into the IPO.