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 JD Vance defeat Kamala Harris in the 2028 presidential election, with Kamala Harris as the Democratic nominee and JD Vance as the Republican nominee?
Vol $0 today · $5.8K total
Will J.D. Vance win the 2028 Republican presidential nomination?
Vol $13.7K today · $15.9M total
Polymarket is 44 points higher than Kalshi (47% vs 4%). They resolve on different dates (Jan 20 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) | 4% | 47% |
| Change (24h) | -0.5 pt | +0.1 pt |
| Volume today | $0 | $13.7K |
| Total volume | $5.8K | $15.9M |
| Liquidity | — | $345.8K |
| Open interest | $4.7K | — |
| Resolves | 27mo | 25mo |
| Tracked for | 9 days | 9 days |
Resolution rules: read both before trusting a gap
Kalshi
If JD Vance defeats Kamala Harris in the 2028 presidential election, 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 Republican Party for U.S. president. Otherwise, this market will resolve to “No”. The resolution source for this market will be a consensus of official Republican Party sources. Any replacement of the Republican 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.