Massachusetts Senate race odds
Kalshi vs Polymarket · updated Oct 20, 1:00 AM ET
Democrats (Ed Markey) to win the Massachusetts Senate race: Kalshi 98.3¢, Polymarket US 98.5¢, Polymarket 98.15¢. The exchanges agree within about a cent. A price of 67¢ means the market implies roughly a 67% chance; it is a price, not a forecast.
Massachusetts Senate betting odds by venue
| Venue | Democrats win | Odds | Bid | Ask | Volume |
|---|---|---|---|---|---|
| Kalshi | 98.3¢ | -5782 | 98.2¢ | 98.4¢ | $25k |
| Polymarket US | 98.5¢ | -6567 | 98¢ | 99¢ | $26k |
| Polymarket | 98.15¢ | -5305 | 98¢ | 98.3¢ | $37k |
Each row prices the outcome it names, in cents; 50¢ is a coin flip. Volume is in each venue’s own units. Full venue comparison
Price history
Last 90 days, Democrats win. Kalshi solid, Polymarket dashed. A break in a line is a gap in the record, not a move.
Polls beside the prices
| Pollster | Fieldwork ends | Sample | Result | Lead |
|---|---|---|---|---|
| MassINC Polling Group | 2026-09-22 | 800 LV | Ed Markey 52 · John Deaton 26 · Joe Tache 2 | +26 |
| University of New Hampshire | 2026-09-21 | 564 LV | Ed Markey 53 · John Deaton 30 · Joe Tache 9 | +23 |
| University of New Hampshire | 2026-08-24 | 881 LV | Ed Markey 49 · John Deaton 30 · Joe Tache 7 | +19 |
| University of New Hampshire | 2026-08-24 | 881 LV | Seth Moulton 38 · John Deaton 25 · Joe Tache 16 | +13 |
| University of Massachusetts Department of Political Science/YouGov | 2026-08-12 | 800 RV | Ed Markey 51 · John Deaton 30 | +21 |
| University of Massachusetts Department of Political Science/YouGov | 2026-08-12 | 800 RV | Seth Moulton 49 · John Deaton 25 | +24 |
Polls: VoteHub (CC BY 4.0). A poll is a separate reading of the same race; the two can differ with neither being wrong.
Common questions
What are the odds in the Massachusetts Senate race?
Democrats (Ed Markey) to win the Massachusetts Senate race: Kalshi 98.3¢, Polymarket US 98.5¢, Polymarket 98.15¢. The exchanges agree within about a cent. A price of 67¢ means the market implies roughly a 67% chance; it is a price, not a forecast.
Why do Kalshi and Polymarket show different prices for the same race?
Each exchange is its own order book with its own traders, fees and rules. A gap of a cent or two is ordinary; a larger gap can come from a thin book or from a settlement-rule difference, which is why each venue links to its own contract.
Is the price a forecast?
No. It is what the best order or last trade implies at that venue. ThinBlimp shows both venues side by side and does not take wagers or give advice.
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