Midterm contracts matched across the venues: 65

Vultax matched 65 midterm contracts across Polymarket and Kalshi. The venues usually sit 1 to 3 points apart, Polymarket prices Democrats higher in 15 of the 18 most-traded outcomes, and $50,000 on a Democratic Senate cost 1.0¢ above the price on Kalshi and 2.4¢ on Polymarket.

- Typical daily gap, 30 days to 12 September: 1.4 pts
- Days Polymarket priced a Democratic House higher: 319 of 379
- $50,000 on a Democratic Senate, above the price: 1.0¢ / 2.4¢

Observed 2026-08-13 to 2026-09-12, population: 15 of 65 matched midterm contract pairs.

Study: https://vultax.com/research/polymarket-vs-kalshi-midterms-odds-2026
Markdown: https://vultax.com/research/polymarket-vs-kalshi-midterms-odds-2026.md
Data: https://vultax.com/research/polymarket-vs-kalshi-midterms-odds-2026/data.json
Share card: https://vultax.com/og/article/research/polymarket-vs-kalshi-midterms-odds-2026
Live screen: https://app.vultax.com/predictions/topic/midterms-2026

Vultax Research, Polymarket vs Kalshi Midterm Odds: 65 Matched Contracts and What a $50,000 Bet Moves, 2026-09-16, https://vultax.com/research/polymarket-vs-kalshi-midterms-odds-2026