Will Seth Moulton be the Democratic nominee for Senate in Massachusetts?

Crossbook compares what two exchanges, Polymarket and Kalshi, charge for the same event, and publishes a permanent scored record of its own forecasts under published rules.

Both venues are priced below, side by side.

Informational only. Not trading or investment advice. Prices may be delayed or inaccurate, and a difference between venues can be an artifact — how this is measured.

Settled, no longer listed0.6pt basisContract settles 1 Sept 2026Last checked 31 Aug 2026, 23:50 UTC

PM0.7%bid 0.1% / ask 1.3%24h volume $288 · liquidity $22Kas of 31 Aug, 23:50 UTC · not refreshed recentlyView on Polymarket

KS1.3%bid 0.3% / ask 1.1%24h volume $1.7M · liquidity –as of 2 Sept, 00:05 UTC · not refreshed recentlyView this market's series on Kalshi

How each venue defines this

Each exchange's own settlement text, quoted as written. Where they differ, the difference is usually why the prices do.

Settles Sep 1, 26

This market will resolve according to the winner of the Democratic Primary for United States Senator from Massachusetts. If no 2026 Massachusetts Democratic Senate Primary takes place, this market will resolve to "Other". The resolution source for this market will be the first announcement of the results from the Massachusetts Democratic party, however an overwhelming consensus of credible reporting may suffice.

Settles Sep 15, 26

If Seth Moulton wins the nomination for the Democratic Party to contest the Class II Massachusetts Senate seat in 2026, then the market resolves to Yes.

Settlement basis

A person confirmed these two markets ask the same question. Their settlement documents have not been compared, so treat the price difference as unverified rather than as a like for like gap.

Confirmed as the same question: Will Seth Moulton be the Democratic nominee for Senate in Massachusetts?

Crossbook forecast

No public Crossbook forecast on this market yet. Every call that is made is timestamped and scored on the public record, win or lose.

Context

Polymarket and Kalshi agree on this one. Both price it near 1%, so there is no cross venue disagreement to trade and no basis to speak of.

Volume over the last 24 hours is heavy, at about $1,694,087 on the busier venue.

This market has settled. The page is kept as a record of what both venues said while the question was open, and of what Crossbook called.

Related markets

Crossbook publishes every forecast it makes, timestamped before the answer is known and scored against the market afterwards. See the public record and the rules it is held to.