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 Jon Ossoff announce a run for President of the United States before Oct 1, 2027?
Vol $210 today · $2.5K total
Will Jon Ossoff win the 2028 Democratic presidential nomination?
Vol $5.1K today · $13.4M total
Kalshi is 21 points higher than Polymarket (35% vs 14%). Polymarket trades about 24.1× more volume today, so its price has more money behind it. They resolve on different dates (Oct 1 vs Nov 8), 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) | 35% | 14% |
| Change (24h) | -4.0 pt | +0.1 pt |
| Volume today | $210 | $5.1K |
| Total volume | $2.5K | $13.4M |
| Liquidity | — | $326.3K |
| Open interest | $1.3K | — |
| Resolves | 12mo | 25mo |
| Tracked for | 9 days | 9 days |
Resolution rules: read both before trusting a gap
Kalshi
If Jon Ossoff has announced that he will run for President of the United States in 2028 before Oct 1, 2027, including running for the nomination of any political party to contest that office, then the market resolves to Yes.
Polymarket
This market will resolve to “Yes” if the named individual wins and accepts the 2028 nomination of the Democratic Party for U.S. president. Otherwise, this market will resolve to “No”. The resolution source for this market will be a consensus of official Democratic Party sources. Any replacement of the democratic nominee before election day will not change the resolution of the market.
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Informational only — not financial advice. Odds are mirrored from each platform and may lag the live order book.