Will Democrats sweep the "core four" Senate races: why do odds differ between prediction markets?

The largest price difference shown across venues is 3.0 percentage points. Venues have different traders, liquidity and fees, so their prices can differ. A price gap alone does not establish an executable arbitrage opportunity; compare settlement rules and the actual buy and sell prices.

Will Democrats sweep the "core four" Senate races: how do prices and payouts work?

For example, Will Democrats win all "core four" senate races at 55.0¢ implies about a 55.0% chance. For a standard $1 contract, a share pays $1 if its outcome settles as correct and $0 if it settles as incorrect. A winning share bought at 40¢ earns 60¢ before fees. Check each venue’s settlement rules, fees and eligibility before trading.

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Kalshi / Polymarket

Will Democrats sweep the "core four" Senate races?

2026-11-03

Best price · tap to trade

Will Democrats win all "core four" senate races54¢1.85x

About This Market

Traders give Will Democrats win all "core four" senate races about a 55.0% chance. Compare prices from Kalshi and Polymarket. The largest cross-platform price difference is 3.0 percentage points.

Polymarket and Kalshi are tracking whether Democrats will sweep the core four Senate races in the upcoming 2026 elections. The outcome could significantly influence the balance of power in the Senate and shape legislative priorities for the following term.

Live Markets

2 platforms

OutcomeConsensus

Kalshi

Polymarket

Best price

Will Democrats win all "core four" senate racesARB

55%

54¢

57¢

1.85x54¢

Platform	Implied %	Yes bid / ask		No bid / ask
Kalshi	53.5%	53¢	54¢	46¢	47¢
Polymarket	56.5%	56¢	57¢	43¢	44¢

Kalshi

Polymarket

Market RulebooksOfficial settlement criteria and edge cases

Official settlement criteria, resolution sources, and edge cases across Kalshi and Polymarket.

Kalshi

Primary Rule

If Democrats win the 2026 Senate elections in ALL of the following states: Georgia, Michigan, North Carolina, AND Maine, then the market resolves to Yes.

Edge Cases

This market requires ALL specified candidates/parties/options to win their respective elections for a Yes resolution. If even one loses, the entire market resolves to No. For parliamentary elections, the party with the most seats wins. For referenda, the specified option must achieve the required threshold. For indirect elections, the ultimate officeholder matters, not intermediate selectors. Postponed elections remain open until rescheduled or two years from original date. Annulled elections remain open until re-run. Death after election but before taking office still counts as a win. In case of ties, the winner through the jurisdiction's tiebreak mechanism prevails. This market is eligible for accelerated determination two days after a consensus of media organizations project the winner. See full rules for details.

Resolution Oracles

Bloomberg Reuters the Associated Press the United Nations Electoral Assistance Division

Polymarket

Primary Rule

This market will resolve to “Yes” if a candidate representing the Democratic Party wins the 2026 midterm U.S. Senate elections in Georgia, Michigan, North Carolina, and Maine (inclusive of any run-offs). A candidate will be considered to represent a party in the event that he or she is the nominee of the party in question. Candidates other than the Democratic nominee (e.g., Greens, Libertarian, independent) will not count. Candidates who run as independents will not be considered a Democrat, regardless of any affiliation they may have with the party. The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call all relevant races for the same candidate. If all three sources don’t call a relevant race for the same candidate, this market will use the official certification of the election results for resolution.

Resolution Oracles

UMA Optimistic Oracle

Frequently Asked Questions

What are the core four Senate races?

The core four Senate races refer to key battleground states that are critical for determining control of the Senate. These races are often closely contested and can swing either way based on voter turnout and campaign strategies.

How do polling data affect the odds in this market?

Polling data provides insights into voter preferences and trends leading up to the elections. As new polls are released, they can cause fluctuations in the odds as markets react to perceived changes in voter sentiment.

What factors could influence the outcome of these races?

Factors such as national political climate, candidate popularity, campaign funding, and key issues affecting voters can all influence the outcome. Additionally, events like debates and major news stories can sway public opinion and impact the races.

Will Democrats sweep the "core four" Senate races: what does this prediction market track?

The outcomes listed above show how traders are pricing this question. Compare outcome prices from Kalshi, Polymarket in one place. Each price reflects the market’s implied probability, not a guaranteed result.

Will Democrats sweep the "core four" Senate races: what are the current odds?

The latest available prices are Will Democrats win all "core four" senate races: 53.5¢ on Kalshi, 56.5¢ on Polymarket. Prices are quoted in cents per $1 share. Check the venue for executable prices and available liquidity.

Will Democrats sweep the "core four" Senate races?

About This Market

Will Democrats sweep the "core four" Senate races?

About This Market

Price History

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Resolution Oracles

Frequently Asked Questions

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Will Democrats sweep the "core four" Senate races?

About This Market

Will Democrats sweep the "core four" Senate races?

About This Market

Price History

Live Markets

Smart Trade Router

Resolution Oracles

Market Rulebook: Will Democrats sweep the "core four" Senate races?

Frequently Asked Questions

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