Market comparison

MA-04 House winner?

2 venues · 2 outcome rows · 2 comparable lines · event identity linked · 0 verified parity · active

Polymarket

Open venue ↗

8 outcomes · $49K reported volume

Observed 1m ago

Recorded venue end date: Nov 4, 2026

Kalshi

Open venue ↗

2 outcomes · $3K reported volume

Observed 3m ago

Recorded venue end date: Nov 3, 2027

Check settlement rules before comparing contracts. Matched outcomes may settle differently. These venues also report end dates more than 48 hours apart; event identity does not mean the contracts close or settle together. These are stored prices; record update times do not certify live quotes. Differences exclude fees and available size.

Known rule differences between venues

Kalshi settles on the party of the officeholder sworn in/inaugurated for the new term; Polymarket settles on the party of the called winner. They differ if the winner dies, withdraws or is not seated before the term starts.
Independents: Polymarket assigns a non-affiliated winner by stated caucus (House) or excludes independents from party options (Senate/Governor); Kalshi requires party membership.
Kalshi may close early on a media-consensus projection; Polymarket resolves on consensus calls with certification as the fallback.

A shared identity alone does not make a price difference executable.

Available outcome prices by venue for MA-04 House winner?
Outcome	Polymarket	Kalshi	Difference
Democratic Partial parity Payoffs match in ordinary outcomes; see the rule differences above.	97.3% Bid 97.2% · Ask 97.3% Jake Auchincloss (D) Open Polymarket ↗	96.4% Bid 96.4% · Ask 98.4% Jake Auchincloss Open Kalshi ↗	0.9 pp
Republican Partial parity Payoffs match in ordinary outcomes; see the rule differences above.	1.8% Bid 0.9% · Ask 2.8% Tom Stalcup (R) Open Polymarket ↗	2.7% Bid 1.2% · Ask 2.7% Tom Stalcup Open Kalshi ↗	0.9 pp