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.
Will Tom Cotton be the next Senate Majority Leader?
Vol $189 today · $9.5K total
Kalshi is 1 points higher than Polymarket (2% vs 0%). Kalshi trades about 27.8× more volume today, so its price has more money behind it. They resolve on different dates (Nov 4 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.
| Polymarket | Kalshi | |
|---|---|---|
| Probability (Yes) | 0% | 2% |
| Change (24h) | +0.0 pt | -2.0 pt |
| Volume today | $189 | $5.3K |
| Total volume | $9.5K | $111K |
| Liquidity | $14.3K | — |
| Open interest | — | $29.4K |
| Resolves | — | 38mo |
| Tracked for | 2 hours | 28 days |
Resolution rules: read both before trusting a gap
Polymarket
This market will resolve according to the individual who is announced as the next Senate Majority Leader after the November 3, 2026, U.S. General Election. This market will remain open until January 3, 2027, at which point it will resolve based on the first announcement of the next Senate Majority Leader from whichever party holds the majority in the U.S. Senate. If no Majority is established and a leader is not announced by June 30, 2027, 11:59 PM ET, this market will resolve to “Other”.
Kalshi
If Tom Holland is cast as the next James Bond before Jan 1, 2030, then the market resolves to Yes.
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Informational only — not financial advice. Odds are mirrored from each platform and may lag the live order book.