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 the Republican party win the House, the Republican party win the Senate, and the Republican party win the Presidency?
Vol $362 today · $102.3K total
Polymarket is 15 points higher than Kalshi (26% vs 11%). Polymarket trades about 930.6× more volume today, so its price has more money behind it. They resolve on different dates (Nov 4 vs Nov 7), 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) | 26% | 11% |
| Change (24h) | -1.0 pt | -0.5 pt |
| Volume today | $337K | $362 |
| Total volume | $4.8M | $102.3K |
| Liquidity | $1.8M | — |
| Open interest | — | $57.3K |
| Resolves | 13d | 37mo |
| Tracked for | 13 days | 13 days |
Resolution rules: read both before trusting a gap
Polymarket
This market will resolve according to the party that wins control of the United States Senate and the party that wins control of the United States House of Representatives in the 2026 United States midterm election. A party wins control of the United States Senate if it wins a majority of the chamber’s voting seats. If no party wins a majority of voting seats, the party that wins control of the chamber is the party that wins half of the voting seats and holds the Vice Presidency. If the outcome remains ambiguous after applying the above criteria, the chamber will be deemed controlled by the party with which the first selected President Pro Tempore of the Congress that convenes after the specified election is affiliated. A party wins control of the United States House of Representatives if it wins a majority of the chamber’s voting seats. If no party wins a majority of voting seats, the chamber will be deemed controlled by the party with which the first elected Speaker of the House of the Congress that convenes after the 2026 midterm election is affiliated. The following rules govern the counting of seats for determining which party wins control of the chambers. For determining Senate control, all regular and special Senate elections that determine representation in the upcoming 120th Congress and are scheduled to take place in November 2026 as of October 31, 2026 are inclu…
Kalshi
If the Republican party wins the House, the Republican party wins the Senate, and the Republican party wins the Presidency in the 2028 election, 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.