The Prediction Markets

Market comparison

How many House seats will the Democrats win in Ohio?

2 venues · 9 outcome rows · 4 comparable lines · event identity linked · 0 verified parity · active

Polymarket

Open venue ↗

7 outcomes · $33K reported volume

Observed 59s ago

Recorded venue end date: Nov 4, 2026

Kalshi

Open venue ↗

7 outcomes · $22K reported volume

Observed 1m 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

  • Seat counts depend on when races are called; venues use different settlement deadlines for uncalled seats.

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

4

Partial parity

Payoffs match in ordinary outcomes; see the rule differences above.

Polymarket

11.5%

Bid 11.0% · Ask 12.0%

4

Open Polymarket ↗

Kalshi

11.0%

Bid 4.0% · Ask 11.0%

4

Open Kalshi ↗

Price difference 0.5 pp

5

Partial parity

Payoffs match in ordinary outcomes; see the rule differences above.

Polymarket

24.0%

Bid 23.0% · Ask 25.0%

5

Open Polymarket ↗

Kalshi

24.0%

Bid 22.0% · Ask 24.0%

5

Open Kalshi ↗

Price difference 0.0 pp

6

Partial parity

Payoffs match in ordinary outcomes; see the rule differences above.

Polymarket

32.0%

Bid 31.0% · Ask 33.0%

6

Open Polymarket ↗

Kalshi

34.0%

Bid 32.0% · Ask 41.0%

6

Open Kalshi ↗

Price difference 2.0 pp

7+

Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Polymarket

28.0%

Bid 27.0% · Ask 29.0%

7+

Open Polymarket ↗

Kalshi

16.0%

Bid 16.0% · Ask 17.0%

7

Open Kalshi ↗

Price difference 12.0 pp

2

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

0.6%

Bid 0.2% · Ask 1.0%

2

Open Polymarket ↗

0.1%

Bid 0.1% · Ask 0.2%

<2

Open Polymarket ↗

Kalshi

—

3

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

2.5%

Bid 2.4% · Ask 2.5%

3

Open Polymarket ↗

Kalshi

—

8

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

—

Kalshi

10.0%

Bid 7.0% · Ask 10.0%

8

Open Kalshi ↗

Above 8

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

—

Kalshi

6.0%

Bid 4.0% · Ask 6.0%

Above 8

Open Kalshi ↗

Below 4

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

—

Kalshi

1.0%

Bid 0.0% · Ask 3.0%

Below 4

Open Kalshi ↗

Prices are shown as percentages of a $1 payout. “pp” means percentage points. A dash means data is unavailable.

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