2026 midterms · data for reporters

Where Kalshi and Polymarket disagree on the 2026 election

The Democratic odds on both prediction markets for Senate control, House control and every Senate race, logged every 5 minutes (every minute on election night), 95 hours so far.

Widest gap so far: Alaska Senate, 1.3 points apart on Nov 9, 9:34 PM ET (Kalshi 98%, Polymarket 99%).

Right now

As of Nov 13, 3:12 PM ET. Gap = points between the two prices for the Democratic side.

Market	Kalshi	Polymarket	Gap
Alaska Senate	100%	100%	0.1

Widest gaps in the last 95 hours

"5+ pts" is roughly how long the two sites were at least 5 points apart.

Market	Widest	When	5+ pts
Alaska Senate	1.3	Nov 9, 9:34 PM ET (K 98%, P 99%)	–
Mississippi Senate	0.4	Nov 11, 8:51 AM ET (K 100%, P 99%)	–

How to read this

Prices are the cheapest offer to buy the Democratic side on each site, which works as the market's odds (62% = 62¢ for a $1 payout), before fees. They aren't the same contract: Kalshi's race markets pay on which party's candidate is sworn in and Polymarket's on the projected winner, so some gap can be the rules, not disagreement. Gaps of a few points during fast news are normal; long, wide gaps are the interesting ones.

Questions or a custom cut of the data for a story: support@arbtrader.co. Live side-by-side odds: arbtrader.co/election. ArbTrader isn't affiliated with Kalshi or Polymarket. Not financial advice.