Polymarket vs. Kalshi
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See where the two biggest prediction markets disagree. Pick any two markets, or start from the biggest gaps below: prices, volume, history and the resolution rules, side by side.
Both markets price this about the same, around 4%. Polymarket trades about 2.1× more volume today, so its price has more money behind it. They resolve on different dates (Jan 1 vs Jan 1), so they may not be exactly the same bet.
History starts when we first saw each market, so a newly added market has a short line.
| Kalshi | Polymarket | |
|---|---|---|
| Probability (Yes) | 5% | 4% |
| Change (24h) | +0.0 pt | +1.0 pt |
| Volume today | $1.9K | $3.9K |
| Total volume | $212.4K | $134.9K |
| Liquidity | — | $29.6K |
| Open interest | $50.2K | — |
| Resolves | 160mo | 14mo |
| Tracked for | 19 days | 16 days |
Resolution rules: read both before trusting a gap
Kalshi
If OpenAI confirms an IPO first, before Jan 1, 2040, then the market resolves to Yes.
Polymarket
This market will resolve based on Anthropic'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 Anthropic’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.
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Informational only — not financial advice. Odds are mirrored from each platform and may lag the live order book.